HS2 Technical Study R12922T101A 4.6 APPENDICES 4.6.1 ... · 4.6.1 Apppendix A - Methodology for...

HS2 Technical Study Site 18/Canterbury Works Site R12922T101A

Pell Frischmann Page 37

4.6 APPENDICES

4.6.1 Apppendix A - Methodology for Townscape and Visual Impact Assessment

4.6.1.1 The methodology for this assessment is based on the ‘Guidelines for Landscape

and Visual Impact Assessment’, 3rd edition, 2014 (Landscape Institute and the

Institute of Environmental Management and Assessment) (GLVIA3). The aim of

these guidelines is to set high standards for the scope and contents of landscape

and visual assessments and to establish certain principles that will help to achieve

consistency, credibility and effectiveness in landscape and visual assessment.

Guidance is contained in this publication on some approaches and techniques

which have been found to be effective and useful in practice by townscape

professionals. However, the guidelines are not intended as a prescriptive set of

rules, nor as an exhaustive manual of techniques.

4.6.1.2 The assessment criteria have been adapted to be relevant to assessment of the

townscape setting of these proposals. Townscape is defined within the GLVIA3

as:

‘...areas where the built environment is dominant. Villages, towns and cities

often make important contributions as elements in wider open landscape

but townscape means the landscape within the built-up area, including

buildings, the relationships between them, the different types of urban

spaces, including green spaces, and the relationship between buildings and

open spaces’

4.6.1.3 The assessment of townscape and visual effects has certain defining features that

distinguish it from the methodologies used in the assessment of landscape and

visual effects. Townscape and visual assessments may also be different from

other specialist studies because they are generally undertaken by professionals

who are also involved in the design of the townscape and the preparation of

subsequent management proposals.

4.6.1.4 A townscape assessment includes a combination of objective and subjective

judgements, and it is therefore important that a structured and consistent

approach is used. It is necessary to differentiate between judgements that involve

a degree of subjective opinion (as in the assessment of townscape values) from

those that are normally more objective and quantifiable (as in the determination of

magnitude of change).

Townscape and Visual Effects 4.6.1.5 Townscape and visual effects are assessed separately.

4.6.1.6 Townscape and visual assessments in this report are dealt with as separate,

although linked, procedures. The townscape baseline, its analysis and the

assessment of townscape effects all contribute to the baseline for visual

assessment studies. The assessment of the potential effect on the townscape is



carried out as an effect on an environmental resource, i.e. the townscape. Visual

effects are assessed as one of the interrelated effects on population.

4.6.1.7 Townscape effects derive from changes in the physical townscape, which may

give rise to changes in its character and how this is experienced. This may in turn

affect the perceived value assigned to the townscape. The description and

analysis of effects on the townscape as a resource relies on the adoption of

certain basic principles about the positive (or beneficial) and negative (or adverse)

effects of change in the townscape.

4.6.1.8 Visual effects relate to the changes that arise in the composition of available views

as a result of changes to the townscape, to people’s responses to the changes,

and to the overall effects with respect to visual amenity.

4.6.1.9 The assessment of effects aims to:

Systematically identify the likely effects of a development;

Indicate the measures proposed to avoid, reduce, remedy or compensate

for those effects (mitigation measures);

Estimate the magnitude of the effects;

Provide an assessment of the nature and significance of these effects in a

logical and well-reasoned fashion.

4.6.1.10 Effects may be positive (beneficial), negative (adverse) or direct or indirect, and

can be secondary or cumulative, permanent or temporary (short, medium or long

term). They can also arise at different scales (local, regional or national) and have

different levels of significance.

Baseline Studies

4.6.1.11 The initial step in any townscape or visual assessment is to review the existing

townscape and visual resource in the vicinity of the development site– that is the

baseline townscape and visual conditions. The data collected will form the basis

from which the current estimation of magnitude and significance of the townscape

and visual effects of the development may be identified and assessed. The

purpose of baseline studies is to record and analyse the existing townscape

features, characteristics, the way the townscape is experienced, and the value or

importance of the townscape and visual resources in the vicinity of the proposed

development. This requires research, classification and analysis of the townscape

and visual resources as follows:

Research/survey involving both desk and field studies to assemble basic

information;

Classification of townscape into units or groups of distinct and

recognisable type and character (Character Area);

Analysis of the townscape in order to understand how it is experienced

and the relative townscape and visual importance of the constituent parts.

4.6.1.12 The desktop study explores patterns and scale of landform, land cover and built

development which gives guidance on the overall townscape character of the

surrounding area. Any special values that may apply, such as designated


Pell Frischmann 9

townscapes or buildings, and specific potential receptors of townscape and visual

impact including important components of the townscape, as well as residents,

visitors, travellers through the area and other groups of viewers have also been

noted.

4.6.1.13 The desk study provides a sound basis for subsequent field survey work including

the identification of townscape character areas around the development site, the

likely zone of visual influence and principal viewpoints. The field survey has

identifies and records specific sensitive receptors.

4.6.1.14 Townscape character assessment, and particularly the stage of characterisation,

is the basic tool for understanding the townscape and is the starting point for

baseline surveys. There is a well established methodology developed in the UK by

the Countryside Agency and Scottish Natural Heritage. The baseline studies

provide a concise description of the existing character of the site and its

surrounding townscape, and the classification of the townscape into distinct

character areas or types, which share common features and characteristics. The

condition of the townscape, i.e. the state of an individual area of townscape,

should be described as factually as possible, and a judgement also needs to be

made on the value or importance to society of the affected townscape. The

assessment of townscape importance includes reference to policy or designations

as an indicator of recognised value, including specific features, or characteristics

that justify the designation of the area. This information is needed as part of the

baseline to establish why the townscape is considered to be of value at a national,

regional or local level.

4.6.1.15 The area of study for the visual assessment may extend to the whole of the area

from which the development is visible (the visual envelope).

4.6.1.16 The approximate visibility of a site as existing should be determined through

survey work and the actual extent of visibility checked in the field because of the

localised screening effect of topography, intervening vegetation and built form.

Principal viewpoints within the area surrounding the site are also identified, and

the viewpoints used for photographs selected to demonstrate the relative visibility

of the site (and existing development on it) and its relationship with the

surrounding townscape and built forms. The selection of the key viewpoints

should be based on the following criteria:

The requirement to provide an even spread of representative viewpoints

within the visual envelope, and around all sides of the site.

From locations which represent a range of near, middle and long distance

views.

Whilst private views are relevant, public viewpoints, i.e. from roads and

public rights of way and other areas of open public access, were selected

since they are the most significant in terms of the number of receptors

affected.

Views from sensitive receptors within designated townscapes.


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4.6.1.17 A study was carried out encompassing groups of properties, roads, public rights of

way and public open space that lie within the visual envelope of a site. The term

"properties" includes dwellings, community facilities and places of employment.

The extent of visibility of the site is based on a grading of degrees of visibility, from

a visual inspection of the site and surrounding area. There is, in any visual

assessment, a continuity of degree of visibility ranging from no view of the site to

full open views. To indicate the degree of visibility of the site from any location,

including from roads, railway lines, public rights of way, public open space and

properties, four categories have been used:

No View: truncated / curtailed / no view of the site or the site is difficult to

perceive;

Partial View: a view of part of the site, or a filtered view of the site, or a

distant view where the site is perceived as a small part of the view;

Transient/Glimpsed View: a quickly passing view of part of the site, or a

fleeting view of the site when passing the site at speed, either from vehicle,

public transport, or when walking/cycling; and

Open View: a clear view of a significant proportion of the site within the

wider townscape.

4.6.1.18 The final stage in the field survey was to identify and address specific sensitive

receptors including townscape elements and features that may be directly affected

by the development, as well as residents, visitors and other groups of viewers. In

the case of townscape receptors, the field survey included the recording of

topographic, geological and drainage features, woodland, tree and hedgerow

cover, land use, field boundaries and artefacts, access and rights of way. In the

case of visual receptors, the types of views affected an estimate of their numbers

and whether there were few or many, duration of viewing, and potential seasonal

screening effects was noted.

4.6.1.19 The next stage in the process was the analysis stage which resulted in the

classification of the townscape into distinctive character areas or types, based on

variations in landform and land cover. The classification took into account the

National townscape character assessments. At the same time as carrying out the

townscape character analysis, conclusions were drawn as to the overall sensitivity

of the townscape and visual environment to the type of development envisaged.

The sensitivity of the townscape to change is reflected in the degree to which the

townscape is able to accommodate change (due to a particular development or

land use change) without adverse effects on its character. This may be influenced

by the extent of existing or new landform and/or existing vegetation or new

planting. These and other factors determine the visibility of the proposed

development and therefore influence the extent of its effect on the perceived

character and visual amenity of the surrounding townscape

4.6.1.20 Following a field survey, the extent to which a site is visible from the surrounding

area is graphically represented with reference to a Visual Appraisal Plan which

illustrates the views into / towards the Site and identifies specific elements such as

landform, buildings or vegetation which interrupt, filter or otherwise influence



views. The locations of principal viewpoints were also mapped and these existing

views are illustrated by annotated photographs (Site Context Photographs). By the

end of this stage of the study, it is possible to advise, in townscape and visual

terms, on a development’s acceptability in principle, and its preferred siting, layout

and design.

Identification and Assessment of Townscape and Visual Effects

4.6.1.21 The assessment of effects aims to:

Identify systematically the likely townscape and visual effects of the

development

Indicate the measures proposed to avoid, reduce, remedy or compensate

for these effects (mitigation measures)

Estimate the magnitude of the effects as accurately as possible;

Provide an assessment of the nature and significance of these effects in a

logical and well-reasoned fashion.

4.6.1.22 Consideration is given to the effects on completion of development at Year 1, and

when the soft townscape proposals are at maturity, so that the residual effects of

the development after mitigation are identified.

Townscape Effects

4.6.1.23 These include the direct and indirect effects of a development on individual

townscape elements and features as well as the effect upon the general

townscape character and quality of the surrounding area. Townscape effects have

been described clearly and objectively, and the extent and duration of any

adverse/beneficial effects quantified, using four categories of effects, indicating a

graduation from high to low (high, medium, low and neutral i.e. no change). Some

effects have been quantified, i.e. how many mature trees are to be lost as a result

of the development proposals, etc. and this type of factual data has the advantage

of helping to put in context the degree of change that will occur.

4.6.1.24 Wider effects on townscape character and quality are less easy to predict

objectively and interpretation and professional judgement will need to be applied.

A clear picture of likely effects is presented by referring back to the baseline

townscape character assessment, and describing how the development may alter

existing patterns of townscape elements and features.

Visual Effects

4.6.1.25 The assessment of visual effects describes:

The changes in the character of the available views resulting from the

development;

The changes in the visual amenity of the visual receptors.



4.6.1.26 The visual effect of a development on a view will depend upon a number of

factors. These can be summarised as:

the nature of the proposal;

its siting in the townscape;

its size;

its detailed design; and

the position from which it is viewed.

4.6.1.27 The position from which the development is viewed (factor (e) above) has two

components, namely distance and location. Distance is the easier of the two

factors to deal with. In general terms, the greater the distance, the less the effect

will be. This arises from two factors. Firstly, doubling the distance between viewer

and object means it’s perceived effect will be reduced not by a half but by a

quarter. Secondly, in any conditions other than clear visibility, increasing the

distance between object and observer will introduce obscuration from rain, haze,

mist or similar atmospheric effects, thereby further reducing the effect of the

object.

4.6.1.28 The net effect of these factors is that the visual impact of an object will begin to fall

away rapidly with increasing distance. Visibility will reduce substantially beyond

1.5 km (1 mile), and beyond 5 km (3 miles). Binoculars of some other aid to

visibility would probably be necessary in order to perceive any detail of the

proposed development.

4.6.1.29 A visual appraisal systematically identifies all the visual receptors (i.e. all

properties or groups of properties, and users of roads and public rights of way)

that are likely to affected by a development, i.e. within the visual envelope of the

development. The term "properties" includes dwellings, public buildings, places of

employment and recreational facilities. The method seeks to assess the impact of

the development in terms of the degree of change in the view experienced by the

observer. This is not a wholly objective methodology, however the results are

presented in a systematic form allowing an informed judgement to be made of the

impact of the development proposals. In the assessment of views there is likely to

be a continuum in the degree of visibility of a development from Open View to No

View, and in order to assist in the description and comparison of the effect on

views, simplified categories were used which considered:

The extent of the view that would be occupied by the development (degree

of visual intrusion): Full, Partial, Glimpse etc;

The proportion of the development or particular features that would be

visible: Full, Most, Small Amount, None;

The distance of the viewpoint from the development and whether the

viewpoint would focus on the development due to proximity, or the

development would form one element in a panoramic view;

Whether the view is transient or one of a sequence of views, as from a

moving vehicle or footpath.



4.6.1.30 Changes in visual amenity may arise from both built or engineered forms, and soft

townscape elements of the development. Consideration should also be given to

the seasonal differences in effects arising from the degree of vegetative screening

and/or filtering of views that would apply in summer and winter. Thus assessment

may be provided for "average" and "worst case" situations (the latter being the

season with least leaf cover and therefore minimal vegetative screening).

Sensitivity of Receptors

4.6.1.31 The sensitivity of visual receptors in views will be dependent on:

The location and context of the viewpoint;

The expectations and occupation or activity of the receptor;

The importance of the view (which may be determined with respect to its

popularity or numbers of people affected, its appearance in guide books,

on tourist maps, and in the facilities provided for its enjoyment and

reference to it in literature or art).

4.6.1.32 The most sensitive receptors may include:

Users of all outdoor recreation facilities, including public rights of way,

whose attention or interest may be focused on the townscape;

Communities where the development results in changes in the townscape

setting or value of views enjoyed by the community;

Occupiers of residential properties with views affected by the development

proposals.

4.6.1.33 Other receptors include people engaged in outdoor sport and recreation, people

travelling through or past the affected townscape in cars, on trains or other

transport routes, and people at their place of work. The least sensitive receptors

are likely to be people at their place of work, or engaged in similar activities whose

attention may be focused on their work or activity, and who therefore may be

potentially less susceptible to changes in the view.

Magnitude of Change

4.6.1.34 In the evaluation of the effects on views and the visual amenity of the identified

receptors, the magnitude of scale or visual change is described by reference to:

The scale of change in the view with respect to the loss or addition of

features in the view and changes in its composition;

The degree of contrast or integration of any new features or changes in the

townscape with the existing or remaining townscape elements;

The duration and nature of the effect, whether temporary or permanent,

intermittent or continuous;

The angle of view in relation to the main activity of the receptor;

The distance of the viewpoint from the proposed development;

The extent of the area over which the changes would be visible.



4.6.1.35 The magnitude of change in the view is assessed in degrees of impact as defined

below:

High: Where the scheme would cause a significant change in the existing

view.

Medium: Where the scheme would cause a noticeable change in the

existing view.

Low: Where the scheme would cause a barely perceptible change in the

existing view.

Neutral: Where the scheme would cause no change in the existing view.

Significance of Effects

4.6.1.36 The two principal criteria determining the significance of effects are the scale or

magnitude of effect, and the environmental sensitivity of the location or receptor. A

higher level of significance is generally attached to large scale effects and effects

on sensitive or high value receptors; thus the small effects on highly sensitive

sites can be more important than large effects on less sensitive sites. It is

therefore important that a balanced and well reasoned judgment of these two

criteria is achieved.

4.6.1.37 In order to develop thresholds of significance, both the sensitivity of receptors and

the magnitude of change must be classified for both townscape receptors and

visual receptors as follows:

Townscape Receptors

Sensitivity Significance Magnitude

Important townscape

components susceptible to small

changes

High Notable change in character over

large area or intensive change

over limited area

Moderately valued townscape

tolerant of change

Medium Moderate change in localised

area

A relatively unimportant

townscape tolerant of change

Low Imperceptible change in

townscape components

Visual Receptors

Sensitivity

Significance Magnitude

Residential Properties, Public

rights of way

High Major change in view for many

viewers



Sports and Recreational

Facilities

Medium Many viewers but moderate

change. Major change but fewer

viewers

Industry/Work places Low Few viewers affected. Minor

change in view

Significance Thresholds

4.6.1.38 These thresholds will be determined by combining sensitivity and magnitude as

set out below. Numerical scoring is not recommended in the “Guidelines for

Townscape and Visual Impact Assessment”. The main factor in deciding

magnitude will be distance from a development site.

Sensitivity Value of

Receptor

Magnitude of Change

High Medium Low

High Major Major/ Moderate Moderate

Medium Major/

Moderate

Moderate Moderate/

Minor

Low Moderate Moderate/ Minor Minor



Effects During Construction

4.6.1.39 It is recognised that project characteristics and hence sources of effects, will vary

through time. The construction, operation, decommissioning and restoration

phases of a development are characterised by quite different physical elements

and activities. In the construction phase, sources of townscape and visual effects

include:

Site access and haulage routes

Materials stockpiles and construction compounds.

Construction equipment and plant

Utilities, including lighting

Protection of existing features

Mitigation

4.6.1.40 The purpose of mitigation is to avoid, reduce and where possible remedy or offset,

any significant, negative (adverse) effects on the environment arising from

development proposals. Mitigation is thus not solely concerned with "damage

limitation", but may also consider measures that could compensate for

unavoidable residual effects. Mitigation measures may be considered under two

categories:

Primary measures that intrinsically comprise part of the development

design through an iterative process;

Secondary measures designed to specifically address the remaining

(residual) negative (adverse) effects of the final development proposals.

4.6.1.41 Strategies to address likely negative (adverse) effects include:

Avoid impact by changing form of development;

Reduce impact by changing form of development;

Remediation of impact, (e.g.) by planting to ‘soften’, absorb and assimilate

development into the townscape;

Compensation of impact, (e.g.) by replacing felled trees with new trees,

and

Enhancement, e.g. creation of new townscape or habitat.

4.6.1.42 Guidelines for Mitigation:

All negative (adverse) townscape and visual effects that are likely to occur

throughout the project life cycle should be considered for mitigation,

although the statutory requirement is limited to significant effects;

Consultation with local community and special interest groups on the

proposed mitigation measures is important;

Townscape mitigation measures should be designed to suit the existing

townscape character and needs of the locality, respecting and building on



local townscape distinctiveness and helping to address any relevant

existing issues in the townscape.

It must be recognised that many mitigation measures, especially planting,

are not immediately effective. Where planting is intended to provide

‘softening’ and assist in ‘visually absorbing’ the development, it may also

be appropriate to assess residual effects for different periods of time, such

as day of opening, Year 1, and at maturity.

The developer should demonstrate a commitment to the implementation of

mitigation measures to agreed programme and budget.

The proposed mitigation measures should address specific issues and

performance standards should be identified for the establishment,

management, maintenance and monitoring of new townscape features.

A programme of appropriate monitoring may be agreed with the regulatory

authority, so that compliance and effectiveness can be readily monitored

and evaluated.

4.6.1.43 Common Mitigation Measures include:

Sensitive location and siting;

Site layout;

Choice of Site level;

Appropriate form, materials and design of buildings. It is not always

practical or desirable to screen buildings. In these cases the scale, design,

colour and texture of building should be carefully considered;

Lighting;

Ground Modelling: for immediate screening effect but may in itself be an

adverse impact unless carefully matched to existing landform;

Planting: Structural planting can help to integrate and soften development

as well as being of potential value as a wildlife habitat; and

Use of camouflage or disguise.

4.6.1.44 Effect of Mitigation on Assessment

4.6.1.45 Where proposed mitigation has the potential to reduce or offset any significant,

negative (adverse) effects on the environment arising from development

proposals this is considered in the assessment and the potential impact after

mitigation explained. The final impact may change over time, for example as

planting becomes established and screen particular views of the site.

Conclusions

4.6.1.46 The conclusion will summarise the Townscape and Visual Impact Assessment

and set out the overall outcome of the assessment, taking into account potential

changes to the site’s context or mitigation.



4.6.2 Appendix B - Townscape Character Areas

PROJECT

Townscape & Visual Assessment - HS2 Proposals for Brent

TITLE

Character Appraisal Plan - Site 18 & Canterbury Works Site

PROJECT No. DRAWING No. REV SCALE

LHC14033 14033_TVIA_01 - 1:2500 @ A3

DATE AUTHOR / CHECKED

10/06/14 JH PO

CHARACTER APPRAISAL KEY

- Site 18/ Canterbury Works Site Boundaries

- Kilburn Lane & Carlton Vale

- West Kilburn

- Queen’s Park

- Paddington Cemetary

APPENDIX B

Kilburn Lane & Carlton Vale

West Kilburn

Queen’s Park

Paddington Cemetary

Site 18

Canterbury Works Site



4.6.3 Appendix C – Visual Appraisal Plan – Site 18

PROJECT


TITLE

Visual Appraisal Plan - Site 18


LHC14033 14033_TVIA_S01 - 1:2500 @ A3


10/06/14 JH PO

Recently Completed Development

Site 11b (Under Construction)

Queen’s Park

Railway Station

Potential Location ofHeadhouse Building

VISUAL APPRAISAL KEY

- Site 18 Boundary

- Approximate Location/Size of Ventshaft Building

- Recently Completed Development / Site with Planning Consent for Development

- Key Building

- Listed Building

- Conservation Area

- South Kilburn Regeneration Area (Local Plan Policy CP9)

- Active / Retail Frontage

- Key Trees

- Public views of the Site

- Glimpsed views of the Site

- Transient views of the Site

- Views of the site from Residential Properties

- Existing Buildings which Visually Enclose Site

APPENDIX C



4.6.4 Appendix D – Photographic Record – Site 18

1

2 SITE 18

PROJECT


TITLE

Site 18 - Photographic Viewpoints 1 & 2


LHC14033 14033_TVIA_S02 - N/A


10/06/14 JH PO

TECHNICAL INFORMATION

DATE TAKEN CAMERA 15th May 2014 Nikon D3100FOCAL LENGTH 35mm (Equivalent to 50mm with 1.5x sensor magnification)

VIEWING DISTANCES

These photographs should be viewed at approx 300mm to visually represent the view seen on site.

VIEWPOINT INFORMATION

1. - Photographic Viewpoint 1 – Claremont RoadThis view is from the eastern end of Claremont Road looking east directly at the site, approximately 20m from the site boundary.

2. - Photographic Viewpoint 2 – Claremont RoadThis photograph has been taken from a point halfway down Claremont Road looking east towards the site, approximately 80m from the site boundary.

Key Plan - (1:5000 Scale)

1

2

APPENDIX D

SITE 18

SITE 18

PROJECT


TITLE



LHC14033 14033_TVIA_S03 - N/A


10/06/14 JH PO



VIEWING DISTANCES



3. - Photographic Viewpoint 3 – Kilburn LaneLooking eastwards towards the site this view has been taken from Kilburn Lane halfway along the row of local shops, approximately 40m from the site boundary.

4. - Photographic Viewpoint 4 – Portnall RoadLocated at the junction of Portnall Road and Kilburn Road looking north towards the site, approximately 20m from the site boundary.

3

4


34

APPENDIX D

SITE 18

SITE 18Key Plan - (1:5000 Scale) 5

6

PROJECT


TITLE



LHC14033 14033_TVIA_S04 - N/A


10/06/14 JH PO



VIEWING DISTANCES



5. - Photographic Viewpoint 5 – Portnall RoadThe photograph shows the view from the pavement adjacent to 224 Portnall Road looking north towards the site, approximately 80m from the site boundary.

6. - Photographic Viewpoint 6 – St Luke’s Church Centre, Kilburn LaneThis view is taken from the pavement adjacent to St Luke’s Church Centre and looks northwest towards the site, approximately 80m from the site boundary.

5

6

APPENDIX D

SITE 18

SITE 18 SITE 187

8


PROJECT


TITLE



LHC14033 14033_TVIA_S05 - N/A


10/06/14 JH PO



VIEWING DISTANCES



7. - Photographic Viewpoint 7 - Fernhead RoadThe view shows The Falcon public house from the end of Fernhead Road looks north-west along Salusbury Road and Kilburn Lane, approximately 110m from the site boundary

8. - Photographic Viewpoint 8 – Western Court, Salusbury RoadThis photograph has been taken from the centre of the terrace known as Western Court and looks north-westwards along Salusbury Road towards The Falcon PH and the site, approximately 180m from the site boundary.

7

8

APPENDIX D

SITE 18

SITE 189

10

PROJECT


TITLE



LHC14033 14033_TVIA_S06 - N/A


10/06/14 JH PO



VIEWING DISTANCES



9. - Photographic Viewpoint 9 –Malvern Road/Carlton ValeThe photograph has been taken from the junction of Malvern Road and Carlton Vale (extending from Salusbury Road), approximately 270m from the site boundary.

10. - Photographic Viewpoint 10 - Salusbury RoadPhotograph 10 is located at the railway bridge on Salusbury Road opposite to the entrance to Queens Park Station looking south-west towards the site, approximately 30m from the site boundary


9

10

APPENDIX D

SITE 18

SITE 18

11

12



VIEWING DISTANCES



11. - Photographic Viewpoint 11 – Salusbury Road/Albert RoadPhotograph 11 is located at the junction of Albert Road and Salusbury Road looking west towards the site, approximately 30m from the site boundary.

12. - Photographic Viewpoint 12 – Salusbury Road/Albert RoadPhotograph 12 is located at the junction of Albert Road and Salusbury Road looking west towards the site, approximately 50m from the site boundary.

PROJECT


TITLE



LHC14033 14033_TVIA_S07 - N/A


10/06/14 JH PO


11

12

APPENDIX D

SITE 18

SITE 1813

14




VIEWING DISTANCES



13. - Photographic Viewpoint 13 – Salusbury RoadThis view shows the views from north of Queens Park railway station looking south along Salusbury Road, approximately 170m from the site boundary

14. - Photographic Viewpoint 14 – Queen’s Park StationThe photograph shows the view from the Queen’s Park railway station looking south towards the site.

PROJECT


TITLE



LHC14033 14033_TVIA_S08 - N/A


10/06/14 JH PO

13

14

APPENDIX D



4.6.5 Appendix E – Visual Appraisal Plan – Canterbury Works Site

PROJECT


TITLE

Visual Appraisal Plan - Canterbury Works Site


LHC14033 14033_TVIA_C01 - 1:2500 @ A3


10/06/14 JH PO

St. Mary’s RC

Primary School

Sorting Office

Canterbury Houseencloses the Sitefrom the South

Potential viewsfrom upper storeys

Kilburn Park Station

Carlton Housescreens views from

the west

Potential Location ofHeadhouse Building

APPENDIX E

VISUAL APPRAISAL KEY

- Canterbury Works Boundary

- Approximate Location/Size of Ventshaft Building

- Recently Completed Development / Site with Planning Consent for Development

- Key Building

- Listed Building

- Conservation Area

- South Kilburn Regeneration Area (Local Plan Policy CP9)

- Active / Retail Frontage

- Key Trees

- Public views of the Site

- Glimpsed views of the Site

- Transient views of the Site

- Views of the site from Residential Properties

- Existing Buildings which Visually Enclose Site



4.6.6 Appendix F - Photographic Record – Canterbury Works Site

CANTERBURY WORKS SITE

15

16




VIEWING DISTANCES



15. - Photographic Viewpoint 15 – Albert RoadThis view is from Albert Road looking east towards the site, approximately 175m from the site boundary.

16. - Photographic Viewpoint 16 – Denmark RoadThis view is from Denmark Road looking east directly towards the site, approximately 115m from the site boundary.

PROJECT


TITLE

Canterbury Works Site - Photographic Viewpoints 15 & 16


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APPENDIX F


17

18




VIEWING DISTANCES



17. - Photographic Viewpoint 17 – Canterbury RoadThis view is from the junction of Canterbury Road and Canterbury Terrace, looking northeast along Canterbury Road, approximately 20m from the site boundary.

18. - Photographic Viewpoint 18 – Chichester RoadThis view is from western end of Chichester Road, at the junction with Canterbury Road, looking northwards towards Canterbury House and the site, approximately 25m from the site boundary.

PROJECT


TITLE



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APPENDIX F

CANTERBURY WORKS SITE19

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VIEWING DISTANCES



19. - Photographic Viewpoint 19 – Canterbury RoadThis view is from Canterbury Road looking directly north towards the site, approximately 10m from the site boundary

20. - Photographic Viewpoint 20 – Cathedral Walk, between Canterbury Road and Coventry Close

This view is from Cathedral Walk, an existing pedestrian route running between Canterbury Road and Coventry Close, approximately 60m from the site boundary looking west towards the site.

PROJECT


TITLE



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APPENDIX F

CANTERBURY WORKS SITE CANTERBURY WORKS SITE



Key Plan - (1:5000 Scale) 21

22 23



VIEWING DISTANCES



21. - Photographic Viewpoint 21 – Coventry Close / Junction with Kilburn High RoadThis view is from the junction between Coventry Close and Kilburn High Road, looking west approximately 410m from the site boundary.

22, 23. - Photographic Viewpoint 22 and 23 – Brondesbury VillasThis view is looking southeast from Brondesbury villas close to Fiona Court residential flats, approximately 120m from the site boundary. View 23 illustrates the effect of the railway.

PROJECT


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Canterbury Works Site - Photographic Viewpoints 21, 22 & 23


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21

APPENDIX F

HS2 Technical Study

Site 18/Canterbury Works Section 5: Air Quality

August 2014

R12922T101-A Submitted by Pell Frischmann

HS2 Technical Study – Section 5: Air Quality Site 18/Canterbury Works Site R12922T101A


This report is to be regarded as confidential to our Client and it is intended for their use only

and may not be assigned. Consequently and in accordance with current practice, any

liability to any third party in respect of the whole or any part of its contents is hereby

expressly excluded. Before the report or any part of it is reproduced or referred to in any

document, circular or statement and before its contents or the contents of any part of it are

disclosed orally to any third party, our written approval as to the form and context of such a

publication or disclosure must be obtained

Prepared for:

Prepared by:

London Borough of Brent

Brent Civic Centre

Engineers Way

Wembley

HA 0FJ

Pell Frischmann

5 Manchester Square

London

W1U 3PD

REVISION RECORD Report Ref: R12922T101A

Rev Description Date Originator Checked Approved

A First Issue 26th August 2014 L Caird P Outen A Twyford



CONTENTS

5. AIR QUALITY ................................................................................................................ 4 5.1 INTRODUCTION ................................................................................................. 4

5.1.1 Introduction ................................................................................................ 4 5.2 HS2 TECHNICAL REVIEW ................................................................................. 5

5.2.1 Introduction ................................................................................................ 5 5.2.2 Technical Review ....................................................................................... 5

5.3 AIR QUALITY ASSESSMENT ............................................................................. 9 5.3.1 Introduction ................................................................................................ 9 5.3.2 Policy Context and Assessment Criteria .................................................. 12 5.3.3 Assessment Approach ............................................................................. 15 5.3.4 Baseline Conditions ................................................................................. 20 5.3.5 Impact Assessment – Site 18 ................................................................... 29 5.3.6 Impact Assessment – Canterbury Works ................................................. 40 5.3.7 Mitigation .................................................................................................. 51 5.3.8 Conclusions.............................................................................................. 52

5.4 REFERENCES .................................................................................................. 53 5.5 GLOSSARY ....................................................................................................... 55 5.6 APPENDICES ................................................................................................... 57

5.6.1 APPENDIX A - Construction Dust Assessment Procedure ...................... 57 5.6.2 APPENDIX B - Impact Descriptors and Assessment of Significance ...... 65 5.6.3 APPENDIC C - Professional Experience ................................................. 68 5.6.4 APPENDIC D - Modelling Methodology ................................................... 69 5.6.5 APPENDIX E – Construction Mitigation ................................................... 79



5. AIR QUALITY

5.1 INTRODUCTION

5.1.1 Introduction

5.1.1.1 The purpose of this report is to examine the suitability of two prospective locations in

Brent as sites for a High Speed Two (HS2) railway tunnel ventilation and emergency

access shaft, with respect to air quality.

5.1.1.2 The proposed HS2 route involves the construction of a number of sections of tunnel

including a 7.4 km tunnel from Euston, into west London through Brent. The tunnels

require ventilation shafts approximately every 3 km along their length. It is proposed to

install three ventilation shafts along the 7.4 km Euston tunnel section, including one

shaft in Brent. This shaft will also be used for access to the tunnels and as an

evacuation route in the case of emergencies.

5.1.1.3 The HS2 proposals have identified a site for a ventilation shaft and transformer station

(known as “Site 18”) at Salusbury Road, to the South of Queens Park station.

However, Site 18 has existing detailed planning consent for a mixed-use

redevelopment as part of the South Kilburn Regeneration Programme, which Brent

Council consider to be highly important to the regeneration of one of London’s most

deprived areas. Brent Council therefore has objections to the location of a ventilation

shaft and transformer station at Site 18 on socio-economic grounds, and has identified

an alternative site for the ventilation shaft at Canterbury Works site, which lies to the

north of Canterbury Road, approximately 500 m to the east of Queens Park station.

5.1.1.4 Aside from the potential socio-economic benefits of locating the ventilation shaft and

transformer station at Canterbury Works rather than Site 18, it is important to consider

the potential environmental impacts of the construction and operation of the ventilation

shaft at either site. The environmental impacts of the use of Site 18 as a ventilation

shaft, transformer station and construction compound have been considered as part of

the environmental assessment work carried out by the HS2 project team. There is a

need, however, to assess the environmental impacts of the Canterbury Works site, and

provide a comparison against the impacts associated with using Site 18.

5.1.1.5 In terms of air quality, the construction of the shaft will involve the excavation of a large

volume of material which has the potential to lead to dust impacts in the surrounding

area. The construction period, which is anticipated to last for 7 years, will also lead to

an increase in heavy goods vehicle movements on local roads, which may lead to air

quality impacts from increased emissions. The operational air quality impacts of the

ventilation shaft are expected to be insignificant as the shaft will not cause any

emissions to air and will not generate a significant volume of road traffic; only a very

small number of movements for service and maintenance.

5.1.1.6 This report provides a technical review of the air quality assessment work undertaken

in production of the HS2 Environmental Impact Assessment (EIA) to determine

whether the potential air quality impacts of construction of a ventilation shaft at Site 18

have been appropriately assessed. The report then describes the methodology and

findings of an independent air quality assessment for Site 18 and Canterbury Works in

order to identify which site is best suited in terms of air quality as a site for an HS2

ventilation and access shaft.



5.2 HS2 TECHNICAL REVIEW

5.2.1 Introduction

5.2.1.1 This section of the report provides a brief summary and review of the air quality

assessment work completed as part of the HS2 Environmental Impact Assessment

(EIA), which relates to the construction and operation of the ventilation shaft and

transformer at Site 18. The review covers the following key documents and

correspondence:

LB Brent formal response to HS2 Environmental Statement;

HS2 ES Scope and Methodology Report;

HS2 Information Paper D8: Tunnel Shafts and Portals;

HS2 ES Community Forum Area Report; and

HS2 ES Air Quality Data Appendix.

5.2.2 Technical Review

5.2.2.1 LB Brent Response to HS2 Environmental Statement

5.2.2.2 As part of the review of the HS2 ES, Brent Council provided a formal consultation

response which raised a number of queries relating to the treatment of Site 18 within

the ES.

5.2.2.3 Brent Council’s response to the ES describes how Site 18 lies within South Kilburn,

which is among the 10 most deprived areas of the UK. The area is undergoing

significant regeneration under the South Kilburn Regeneration Programme, and as part

of this, detailed planning consent has been granted for a residential-led mixed-use

development at Site 18, which includes 137 apartments, 1,270 sqm of commercial

space (A1/A3/A4) and 959 sqm of office space (for TfL). This redevelopment is seen

as highly important to the regeneration of the area, and as such, Brent Council

expressed its concerns at the lack of consideration of alternatives to Site 18 for an HS2

vent shaft and transformer station.

5.2.2.4 Brent Council considers the assessment of likely significant effects of Site 18

presented within the HS2 ES to be inadequate and incomplete and does not sufficiently

consider alternative sites or mitigation measures.

5.2.2.5 London to West Midlands ES Volume 5 Scope and Methodology Report

5.2.2.6 The London to West Midlands ES Volume 5 Scope and Methodology Report provides

a brief outline of the adopted assessment methodology for each of the HS2 ES chapter

topics, including air quality.

5.2.2.7 The methodology report covers the whole London to Birmingham Phase 1 route and is

therefore fairly high-level. In terms of the assessment of Site 18, the key elements of

the assessment relating to air quality are emissions from construction traffic on site and

on local roads and emissions of dust from construction activities such as vent shaft

excavation. The methodology report makes it clear that emissions from construction

traffic will only be assessed where the volume of traffic movements generated will

exceed 200 movements per day for HGVs and/or an increase in total traffic flows of

more than 1,000 movements per day. This is consistent with DMRB screening criteria



published by the Highways Agency. It is understood that the predicted construction

traffic generation from Site 18 does not exceed these criteria, and therefore the

assessment of significant effects in the HS2 ES does not specifically include the impact

of Site 18 in terms of air quality from construction traffic emissions.

5.2.2.8 In terms of the emissions from construction activities, the methodology report describes

that these activities will be assessed using a risk-assessment methodology published

in guidance by the Institute of Air Quality Management (IAQM). The assessment

provided later in this report follows a recently updated version of the IAQM approach.

5.2.2.9 HS2 Information Paper D8: Tunnel Shafts and Portals

5.2.2.10 The HS2 Information Paper D8: Tunnel Shafts and Portals contains descriptions and

illustrations of the proposed ventilation shafts, their purpose and their design. This

section includes a summary of the pertinent details contained within the D8 information

paper.

5.2.2.11 There will be three tunnel sections on the London to West Midlands HS2 route. These

include a 7.4 km tunnel section from west London through Brent to Euston. The

tunnels require sufficient ventilation, which is to be provided by vent shafts which will

allow: a conduit to enable smoke to escape from the tunnels in the event of fire;

emergency access; and sufficient air flow to ensure a comfortable environment within

the tunnels.

5.2.2.12 The vent shafts will be located approximately every 3 km along all HS2 tunnel sections,

which is designed to be consistent with the ‘tried and tested’ ventilation system

employed on the HS1 tunnels. The 7.4 km Euston tunnel will have three vent shafts

along its length.

5.2.2.13 The vent shafts will operate via the piston effect, by which air will be forced out of the

vent shaft by an approaching train, and air will be drawn back down through the vent

shaft in the wake of a passing train.

5.2.2.14 London to West Midlands ES Volume 2 Community Forum Area Report

5.2.2.15 Description of Construction Works

5.2.2.16 Within the London to West Midlands Environmental Statement Volume 2 Community

Forum Area report for CFA-4 (Kilburn (Brent) to Old Oak Common) paragraphs 2.4.31

to 2.4.36 discuss the construction works that will be undertaken at Site 18.

5.2.2.17 The report outlines the following principal elements of the works that will be undertaken

at Site 18 between 2018 and 2024:

site clearance and enabling works;

building demolition;

vent shaft construction;

vent shaft internal structures civil engineering and building works;

excavation and construction of short connecting tunnels between the vent shaft

and the tunnels;

headhouse construction;

railway systems installation including installation of an auto transformer station

and fit-out of the vent shaft and headhouse; and

landscaping.



5.2.2.18 Construction work on the ventilation shaft will begin in 2018 and run for two and a half

years, followed by a two-year break in activity at Site 18, followed by a final two and a

half years of civil engineering, mechanical and electrical works at the site.

5.2.2.19 The works outlined above have the potential to generate dust and PM10, the potential

impacts of which are considered in the HS2 ES Volume 5, and are independently

assessed in the Air Quality Assessment section of this report.

5.2.2.20 Air Quality

5.2.2.21 The London to West Midlands Environmental Statement Volume 2 Community Forum

Area report for CFA-4 (Kilburn (Brent) to Old Oak Common) also contains a section on

air quality. The section is a summary of the assessment of operational and

construction period air quality impacts of the entire CFA-4 area, and does not provide

sufficient detail to draw any conclusions on the impacts of the vent shaft at Site 18.

5.2.2.22 London to West Midlands ES Volume 5 Air Quality Data Appendix

5.2.2.23 The London to West Midlands ES Volume 5 Technical Appendices includes a data

appendix for air quality for the CFA-4 Kilburn (Brent) to Old Oak Common area

(document ref: AQ-001-004). The data appendix outlines the results of the operational

and construction period air quality assessment in the CFA-4 area.

5.2.2.24 The data appendix covers construction and operation across the whole CFA-4 area

and there is very little assessment of Site 18 in isolation. In terms of construction and

operational road traffic impacts, the traffic generated by Site 18 is included in predicted

traffic generation from all elements of construction and demolition across the CFA-4

area and therefore it is not possible to disseminate the contribution of Site 18 to

predicted increases in roadside pollutant concentrations.

5.2.2.25 In terms of emissions from operational road traffic generation, the air quality

assessment concludes that the impacts range in magnitude from negligible to

moderate adverse, but these impacts are judged to be insignificant at all locations

other than Old Oak Lane, where the authors judge there to be potentially significant air

quality effects (relating to concentrations of nitrogen dioxide). It is unlikely that this will

be predominantly caused by Site 18 operational traffic.

5.2.2.26 In terms of emissions from construction traffic, the air quality assessment concludes

that there is a potential for significant air quality effects relating to concentrations of

nitrogen dioxide at Shaftesbury Gardens, Victoria Terrace, Wales Farm Road, Old Oak

Lane and Edgeware Road. It is unlikely that these will be predominantly caused by Ste

18 construction traffic, but it may be a contributory factor.

5.2.2.27 In terms of the impacts of dust from construction, a qualitative risk assessment

approach has been undertaken, which includes examination of different construction

compounds, including Site 18, individually. The assessment focusses on four separate

elements of construction, which are: demolition, earthworks, construction and trackout.

The assessment has found the impacts of activities at Site 18 to be negligible in terms

of demolition and slight adverse in terms of earthworks, construction and trackout.

These findings are based on the introduction of a suite of recommended mitigation

measures to reduce dust emissions. Overall, the authors conclude that this does not

represent a significant effect.



5.2.2.28 It should be noted that the assessment of impacts from construction dust utilises a

methodology which has recently been updated and superseded. The independent

construction dust assessments for Site 18 and Canterbury Works included later in this

report have been carried out using the updated IAQM methodology.

5.2.2.29 Overall, the environmental assessment work completed in support of the HS2 London

to West Midlands scheme, did not address the air quality impacts of the construction

and operation of a ventilation shaft and auto transformer at Site 18 in a high level of

detail and therefore it is not possible to identify what the specific air quality impacts

would be. The second part of this report outlines the methodology and results of a

detailed air quality assessment for both Site 18 and the alternative proposed site at

Canterbury Works.



5.3 AIR QUALITY ASSESSMENT

5.3.1 Introduction

5.3.1.1 This report describes the potential air quality impacts associated with the construction

and operation of the proposed HS2 railway ventilation shaft and auto transformer

station at two prospective sites in the London Borough of Brent. The prospective sites

are referred to in this assessment as “Site 18” and “Canterbury Works”. The

assessment has been carried out by Air Quality Consultants Ltd on behalf of London

Borough of Brent.

5.3.1.2 The proposed development will consist of the construction and operation of a shaft to

provide ventilation and emergency access to a 7.6 km section of HS2 railway tunnel

between Old Oak Common in Kilburn, west London, and Euston. The chosen site will

also host an auto transformer station which will provide power to a section of the HS2

railway and it’s infrastructure.

5.3.1.3 There is a potential for air quality impacts associated with:

1) emissions of dust and PM10 from excavation and construction of the ventilation

shaft, construction of the transformer, demolition of existing buildings on the

chosen site, on-site earthworks, and the trackout of dust onto the local road

network by construction vehicles;

2) emissions of nitrogen dioxide, PM10 and PM2.5 from construction traffic

movements on the adjacent road network;

3) emissions of nitrogen dioxide, PM10 and PM2.5 from construction traffic and plant

operating on the construction site;

4) emissions of nitrogen dioxide, PM10 and PM2.5 from operational traffic

movements on the adjacent road network; and

5) emissions from the operation of the tunnel ventilation shaft.

5.3.1.4 In terms of emissions from the operation of the ventilation shaft (item 5); the HS2

railway will be electrified and no diesel-powered locomotives will use the Old Oak

Common to Euston HS2 tunnel. Therefore, there will not be any direct emissions from

the ventilation shaft during operation and the air quality impacts have thus not been

assessed.

5.3.1.5 In terms of operational road traffic (item 4), the ventilation shaft and transformer will not

require a significant level of staffing, and therefore operational road traffic movements

are anticipated to be restricted to a very small number of service and maintenance

movements. The air quality impacts associated with these vehicle movements have

not been included in the assessment as they are judged to be insignificant in terms of

air quality.

5.3.1.6 The operation of construction vehicles and plant on the construction site itself (item 3)

is not clearly defined, and is likely to be limited. The emissions from such plant and

vehicle use has not been included in this assessment; however, some basic mitigation

measures relating to the location and use of on-site plant is included in the assessment

of construction activities. The air quality impacts of on-site plant and construction

vehicles is judged to be insignificant with respect to air quality.



5.3.1.7 The assessment set out in this report therefore only includes an assessment of items 1

and 2, relating to emissions of dust and PM10 during construction, and exhaust

emissions from construction traffic on the adjacent road network.

5.3.1.8 The assessment has been prepared taking into account all relevant local and national

guidance and regulations, and follows a methodology agreed with Brent Council.

5.3.1.9 Site 18

5.3.1.10 Site 18 is located adjacent to Salusbury Road, immediately to the south of Queens

Park station. It is bounded by Queens Park station to the north, Salusbury Road to the

east, Claremont Road to the west and Kilburn Lane to the south. Site 18 currently

consists of an existing TfL office and some light industrial buildings.

5.3.1.11 There is existing detailed planning permission for a residential-led, mixed-use

development at Site 18 as part of the South Kilburn Regeneration Programme. Brent

Council regards this site as of importance with respect to regeneration in Kilburn and

oppose the use of the site for an HS2 ventilation shaft and transformer on the basis of

socio-economic considerations. A map showing the location of Site 18 is presented in

Figure 5.1.

Figure 5.1: Site 18 Location

Contains Ordnance Survey data © Crown copyright and database right [2014]

5.3.1.13 Canterbury Works

5.3.1.14 The Canterbury Works site is located adjacent to St Mary’s Roman Catholic Primary

School at Canterbury Road. It is bounded by the school to the east, by the mainline

railway to London Euston to the north, by Canterbury Road to the south and by



residential apartment buildings to the west. The site is currently occupied by an old

office building and some light industrial and commercial buildings.

5.3.1.15 The Canterbury Works site has existing planning permission for a change of use from

office (B1) to residential (C3), granted in November 2013. No construction work on the

site has started to date. The location of the Canterbury Works site is shown in Figure

5.2.

Figure 5.2: Canterbury Works Location




5.3.2 Policy Context and Assessment Criteria

5.3.2.1 Air Quality Strategy

5.3.2.2 The Air Quality Strategy published by the Department for Environment, Food, and

Rural Affairs (Defra) provides the policy framework (Defra, 2007) for air quality

management and assessment in the UK. It provides air quality standards and

objectives for key air pollutants, which are designed to protect human health and the

environment. It also sets out how the different sectors: industry, transport and local

government, can contribute to achieving the air quality objectives. Local authorities are

seen to play a particularly important role. The strategy describes the Local Air Quality

Management (LAQM) regime that has been established, whereby every authority has

to carry out regular reviews and assessments of air quality in its area to identify

whether the objectives have been, or will be, achieved at relevant locations, by the

applicable date. If this is not the case, the authority must declare an Air Quality

Management Area (AQMA), and prepare an action plan which identifies appropriate

measures that will be introduced in pursuit of the objectives.

5.3.2.3 Planning Policy

5.3.2.4 National Policies

5.3.2.5 The National Planning Policy Framework (NPPF) (2012) sets out planning policy for

England in one place. It places a general presumption in favour of sustainable

development, stressing the importance of local development plans, and states that the

planning system should perform an environmental role to minimise pollution. One of

the twelve core planning principles notes that planning should “contribute to…reducing

pollution”. To prevent unacceptable risks from air pollution, planning decisions should

ensure that new development is appropriate for its location. The NPPF states that the

effects of pollution on health and the sensitivity of the area and the development should

be taken into account.

5.3.2.6 More specifically the NPPF makes clear that: “Planning policies should sustain

compliance with and contribute towards EU limit values or national objectives for

pollutants, taking into account the presence of Air Quality Management Areas and the

cumulative impacts on air quality from individual sites in local areas. Planning

decisions should ensure that any new development in Air Quality Management Areas

is consistent with the local air quality action plan.”.

5.3.2.7 The NPPF is now supported by Planning Practice Guidance (PPG) (DCLG, 2014),

which includes guiding principles on how planning can take account of the impacts of

new development on air quality. The PPG states that “Defra carries out an annual

national assessment of air quality using modelling and monitoring to determine

compliance with EU Limit Values.” and “It is important that the potential impact of new

development on air quality is taken into account … where the national assessment

indicates that relevant limits have been exceeded or are near the limit”. The role of the

local authorities is covered by the LAQM regime, with the PPG stating that local

authority Air Quality Action Plans “identify measures that will be introduced in pursuit of

the objectives”.

5.3.2.8 The PPG states that “Whether or not air quality is relevant to a planning decision will

depend on the proposed development and its location. Concerns could arise if the



development is likely to generate air quality impact in an area where air quality is

known to be poor. They could also arise where the development is likely to adversely

impact upon the implementation of air quality strategies and action plans and/or, in

particular, lead to a breach of EU legislation (including that applicable to wildlife)”.

5.3.2.9 The PPG sets out the information that may be required in an air quality assessment,

making clear that “Assessments should be proportional to the nature and scale of

development proposed and the level of concern about air quality”. It also provides

guidance on options for mitigating air quality impacts, as well as examples of the types

of measures to be considered. It makes clear that “Mitigation options where

necessary, will depend on the proposed development and should be proportionate to

the likely impact”.

5.3.2.10 Air Quality Action Plan

5.3.2.11 The LB of Brent has declared an AQMA for nitrogen dioxide and PM10 that covers the

south of the borough and the major roads in the north. The Council has since

developed an Air Quality Action Plan (LB of Brent, 2005). This sets out a number of

measures to reduce the impact of emissions from vehicles within the borough.

5.3.2.12 Assessment Criteria

5.3.2.13 Health Criteria

5.3.2.14 The Government has established a set of air quality standards and objectives to

protect human health. The ‘standards’ are set as concentrations below which effects

are unlikely even in sensitive population groups, or below which risks to public health

would be exceedingly small. They are based purely upon the scientific and medical

evidence of the effects of an individual pollutant. The ‘objectives’ set out the extent to

which the Government expects the standards to be achieved by a certain date. They

take account of economic efficiency, practicability, technical feasibility and timescale.

The objectives for use by local authorities are prescribed within the Air Quality

(England) Regulations, 2000, Statutory Instrument 928 (2000) and the Air Quality

(England) (Amendment) Regulations 2002, Statutory Instrument 3043 (2002).

5.3.2.15 The objectives for nitrogen dioxide and PM10 were to have been achieved by 2005 and

2004 respectively, and continue to apply in all future years thereafter. The PM2.5

objective is to be achieved by 2020. Measurements across the UK have shown that

the 1-hour nitrogen dioxide objective is unlikely to be exceeded where the annual mean

concentration is below 60 g/m3 (Defra, 2009).

5.3.2.16 The European Union has also set limit values for nitrogen dioxide, PM10 and PM2.5.

Achievement of these values is a national obligation rather than a local one (Directive

2008/50/EC of the European Parliament and of the Council, 2008). The limit values for

nitrogen dioxide are the same levels as the UK objectives, but applied from 2010 (The

Air Quality Standards Regulations (No. 1001), 2010). The limit values for PM10 and

PM2.5 are also the same level as the UK statutory objectives, but applied from 2005 for

PM10 and will apply from 2015 for PM2.5.

5.3.2.17 The relevant air quality criteria for this assessment are provided in Table 5.1.



Table 5.1: Air Quality Criteria for Nitrogen Dioxide, PM10 and PM2.5

Pollutant Time Period Objective

Nitrogen

Dioxide

1-hour Mean 200 g/m3 not to be exceeded more than 18 times a

year

Annual Mean 40 g/m3

Fine

Particles

(PM10)

24-hour Mean 50 g/m3 not to be exceeded more than 35 times a

year

Annual Mean 40 g/m3

Fine

Particles

(PM2.5) a

Annual Mean 25 µg/m3

a The PM2.5 objective, which is to be met by 2020, is not in Regulations and there is no

requirement for local authorities to meet it.

5.3.2.18 Construction Dust Criteria 5.3.2.19 There are no formal assessment criteria for dust. In the absence of formal criteria, the

approach developed by the Institute of Air Quality Management (IAQM) (2014) has been used. Full details of this approach are provided in Appendix A.

5.3.2.20 Descriptors for Air Quality Impacts and Assessment of Significance

5.3.2.21 Construction Dust Significance

5.3.2.22 Guidance from the IAQM (Institute of Air Quality Management, 2014) is that, with

appropriate mitigation in place, the impacts of construction dust will not be significant.

The assessment thus focuses on determining the appropriate level of mitigation so as

to ensure that impacts will normally not be significant.

5.3.2.23 Construction Traffic Significance

5.3.2.24 There is no official guidance in the UK on how to describe air quality impacts, nor how

to assess their significance. The approach developed by the IAQM1 (Institute of Air

Quality Management, 2009), and incorporated in Environmental Protection UK’s

(EPUK’s) guidance document on planning and air quality (Environmental Protection

UK, 2010), has therefore been used. This approach includes elements of professional

judgement. Full details of this approach are provided in Appendix B, with the

professional experience of the consultants preparing the report set out in Appendix C.

1 The IAQM is the professional body for air quality practitioners in the UK.



5.3.3 Assessment Approach

5.3.3.1 Consultation

5.3.3.2 The assessment follows a methodology agreed with Brent Council via a telephone

discussion and email correspondence between Jennifer Barrett (Brent Council) and

Laurence Caird (Air Quality Consultants) held on in June/July 2014.

5.3.3.3 Existing Conditions

5.3.3.4 Existing sources of emissions within the study area have been defined using a number

of approaches. A site visit has been carried out to identify existing sources from a

visual inspection of the area. Industrial and waste management sources that may

affect baseline air quality in the area have been identified using Defra’s Pollutant

Release and Transfer Register (Defra, 2014d) and the Environment Agency’s website

‘what’s in your backyard’ (Environment Agency, 2014). Local sources have also been

identified through examination of the Council’s Air Quality Review and Assessment

reports.

5.3.3.5 Information on existing air quality has been obtained by collating the results of

monitoring carried out by the local authority. The background concentrations across

the study area have been defined using the national pollution maps published by Defra

(2014a). These cover the whole country on a 1x1 km grid.

5.3.3.6 Construction Dust Impacts

5.3.3.7 The assessment of dust and PM10 from construction activities considers the potential

for impacts within 350 m of the site boundary; or within 50 m of roads used by

construction vehicles. The assessment methodology is that provided by the IAQM

(Institute of Air Quality Management, 2014). This is based around a sequence of

steps. Step 1 is a basic screening stage, to determine whether the more detailed

assessment provided in Step 2 is required. Step 2a determines the potential for dust to

be raised from on-site works and by vehicles leaving the site. Step 2b defines the

sensitivity of the area to any dust that may be raised. Step 2c combines the

information from Steps 2a and 2b to determine the risk of dust impacts without

appropriate mitigation. Step 3 uses this information to determine the appropriate level

of mitigation required to ensure that there should be no significant impacts.

5.3.3.8 It should be noted that the IAQM methodology described above is an updated version

of the methodology used by the HS2 consultancy team to assess the impacts of

construction activities across the London to West Midlands HS2 route. Appendix A

explains the approach in more detail.

5.3.3.9 Construction Traffic Impacts

5.3.3.10 The assessment of air quality impacts from construction traffic exhaust emissions

utilises a detailed dispersion modelling methodology, which is described in this section

of the report, with further details provided in Appendix D.

5.3.3.11 Study Area

5.3.3.12 Site 18 and Canterbury Works are both located within 500 m of each other, and as

such the assessment has focussed upon the same study area for both sites.



Construction traffic is anticipated to have the same origin and destination regardless of

which site is chosen for the ventilation shaft, and therefore the same roads are

expected to be affected by changes in traffic. The exception to this is Albert Road,

Canterbury Terrace and Canterbury Road, which will only be affected by construction

traffic if Canterbury Works becomes the chosen site. The assessment study area is

outlined in Figure D.1.

5.3.3.13 Sensitive Locations

5.3.3.14 Concentrations of nitrogen dioxide, PM10 and PM2.5 have been predicted at a number of

locations close to roads that will be used by construction traffic to access the Site 18

and/or Canterbury Works sites. Receptors have been identified to represent worst-case

exposure within these locations. When selecting these receptors, particular attention

has been paid to assessing impacts close to junctions, where traffic may become

congested, and where there is a combined effect of several road links. The receptors

have been located on the façades of the properties closest to the sources.

5.3.3.15 A total of 40 existing residential properties have been identified as receptors for the

assessment. These locations are described in Table 5.2 and shown in Figure 5.3.

5.3.3.16 It has been assumed that all construction traffic will access the sites via either

Salusbury Road or Kilburn Lane (plus Albert Road and Canterbury Road for the

Canterbury Works site). Beyond this, the origin and destination of construction

vehicles is not known and therefore the assessment does not examine a wider study

area.

5.3.3.17 In addition, concentrations have been modelled at the diffusion tube monitoring sites

located at Kilburn Park Road and Chamberlayne Road in order to verify the modelled

results (see Appendix D for verification method).



Table 5.2: Sensitive Receptor Locations a

Receptor Grid Reference

(X,Y)

Description

Receptor 1 525141,183323 St Mary’s Primary School

Receptor 2 525169,183273 Cathedral Walk

Receptor 3 525152,183256 111a Canterbury Road

Receptor 4 525105,183208 103 Canterbury Road

Receptor 5 525096,183229 Carlton House 1-8





Receptor 10 524965,183275 Albert Road Apartment


Receptor 12 524935,183242 Denmark Road Apartment



Receptor 15 524772,183167 1 Albert Road

Receptor 16 524722,183142 William Dunbar House

Receptor 17 524724,183119 William Dunbar House

Receptor 18 524648,183075 346A Kilburn Lane

Receptor 19 524533,183092 289 Kilburn Lane

Receptor 20 524441,183059 282 Kilburn Road








Receptor 26 523884,182898 Apartments at Kilburn Lane

Receptor 27 523871,182893 1 Banister Road

Receptor 28 523778,182855 Flats at Chamberlayne Road

Receptor 29 523785,182841 30 Chamberlayne Road

Receptor 30 524650,183097 Premier Corner 1




Receptor 34 524627,183269 51 Salusbury Road







a Receptors modelled at a height of 1.5 m or 4.5 m relevant to residential exposure at

ground-floor or first-floor levels respectively.



Figure 5.3: Receptor Locations




5.3.3.18 Assessment Scenarios

5.3.3.19 Predictions of nitrogen dioxide, PM10 and PM2.5 concentrations have been carried out

for a base year (2013), and the proposed year of commencement of construction

(2018). For 2018, a sensitivity test has been carried out for nitrogen dioxide that

involves assuming no reduction in emission factors for road traffic from the baseline

year. This is to address the issue identified by Defra (Carslaw, Beevers,

Westmoreland, & Williams, 2011) that road traffic emissions have not been declining

as expected (see later section on uncertainty). Nitrogen dioxide concentrations in 2018

with and without the scheme are thus presented for two scenarios: ‘With Emissions

Reduction’ and ‘Without Emissions Reduction’.

5.3.3.20 It is currently expected that road traffic emissions and background pollutant

concentrations will decrease year on year in the future due to improvements in vehicle

emissions technologies and reductions in pollutant emissions across other sectors

such as industry, shipping and rail. The assessment of the proposed year of

commencement of construction ought to therefore represent a worst-case assessment

and will be used as an indicator for potential air quality impacts in all subsequent years

of construction (the construction period is predicted to last 7 years).

5.3.3.21 Modelling Methodology

5.3.3.22 Concentrations have been predicted using the ADMS-Roads dispersion model. Details

of the model inputs and the model verification are provided in Appendix D, together

with the method used to derive background nitrogen dioxide concentrations.

5.3.4 Baseline Conditions

5.3.4.1 Industrial sources

5.3.4.2 A search of the UK Pollutant Release and Transfer Register (Defra, 2014d) and

Environment Agency’s ‘what’s in your backyard’ (Environment Agency, 2014) websites

did not identify any significant industrial or waste management sources that are likely to

affect the proposed development, in terms of air quality.

5.3.4.3 Site Visit

5.3.4.4 A site visit was carried out on 6th June 2014. Other than road traffic, no significant

sources of air pollution were identified during the site visit.

5.3.4.5 Air Quality Review and Assessment

5.3.4.6 The London Borough of Brent has investigated air quality within its area as part of its

responsibilities under the LAQM regime. In April 2001, the Council declared an Air

Quality Management Area (AQMA) in respect of potential exceedences of the annual

mean objective for nitrogen dioxide and the daily mean objective for PM10. The AQMA

was later extended in 2006, and the boundary now includes the southern half of the

Borough, and corridors to the north along the A404, A4140, A4006 and A5. The Site

18 and Canterbury Works sites are both located within the designated AQMA. The

Updating and Screening Assessment undertaken by the Council in 2012 identified

measured exceedences outside the designated AQMA at Harrow Road and at the



junction of Shaftesbury Avenue and Woodcock Hill and recommended that a detailed

assessment should be undertaken in these locations.

5.3.4.7 Local Air Quality Monitoring

5.3.4.8 The London Borough of Brent operates three automatic monitoring stations within its

area. None of these are in close proximity to Site 18 or the Canterbury Works. The

Council did, however, operate an automatic monitoring station at St Mary’s Primary

School, adjacent to the Canterbury Works site. The St Mary’s Primary School station

was decommissioned at the start of 2011. The Council also operates a number of

nitrogen dioxide monitoring sites using diffusion tubes prepared and analysed by

Gradko International Ltd (using the 50% TEA in acetone method). These include three

tubes deployed near to Site 18 and Canterbury Works, at Kilburn Park Road,

Chamberlayne Road and Kilburn Bridge. Results for the years 2008 to 2013 are

summarised in Table 5.3 and the monitoring locations are shown in Figure 5.4.

Table 5.3:Summary of Nitrogen Dioxide (NO2) Monitoring (2008-2013) a

Site

No.

Site Type Location 2008 2009 2010 2011 2012 2013

Automatic Monitor - Annual Mean (µg/m3)

Urban

Background

St Mary’s

Primary School

34.8 35.8 35.3 - - -

Objective 40

Automatic Monitor - No. of Hours > 200 µg/m3

Urban

Background

St Mary’s

Primary School

0 4 0 - - -

Objective 18

Diffusion Tubes - Annual Mean (µg/m3) b

BRT48 Roadside Kilburn Park Rd

near junction

with Shirland

Rd

82.2 74.0 65.7 69.3 76.6 70.5

BRT56 Roadside Chamberlayne

Road

78.3 70.3 62.5 66.5 75.2 70.1

BRT57 Roadside Kilburn Bridge 119.3 84.2 76.3 81.6 100.8 88.0

Objective 40

a Exceedences of the objectives are shown in bold



b 2008-2012 data have been taken from the 2013 Progress Report (London Borough of

Brent, 2013). 2013 data have been provided by the LB Brent. All data have been

bias adjusted by the Council.

5.3.4.9 The monitoring results presented in Table 5.3 show that roadside nitrogen dioxide

concentrations are well over the annual mean objective, and are capable of exceeding

the objective by more than 100%. There are no clear trends in monitoring results for

the past six years. This contrasts with the expected decline due to the progressive

introduction of new vehicles operating to more stringent standards. The implications of

this are discussed in Section 5.3.5Error! Reference source not found. of this report.

Figure 5.4: Monitoring Locations




5.3.4.10 The St Mary’s Primary School automatic monitoring station also measured PM10

concentrations up to the end of 2010. Results are summarised in Table 5.4.

5.3.4.11 As the St Mary’s site is at a background location, results of PM10 monitoring at the

nearest roadside PM10 monitor to Site 18 and Canterbury Works (located at John Keble

School adjacent to the A404 Manor Park Road) have also been included in Table 5.4.

There are no monitors measuring PM2.5 concentrations near to Site 18 or Canterbury

Works.

Table 5.4: Summary of PM10 Automatic Monitoring (2008-2013) a

Site

No.

Site Type Location 2008 2009 2010 2011 2012 2013

PM10 Annual Mean (µg/m3)

Background St Mary’s

Primary School

- 21 20 - - -

Roadside John Keble

Primary School

24 23 - - 24 25

Objective 40

PM10 No. Days >50 µg/m3

Background St Mary’s

Primary School

- 5 2 - - -

Roadside John Keble

Primary School

8 7 - - 11 10

Objective 35

a Data downloaded from the London Air Quality Network website (King's College

London, 2014).

5.3.4.12 The results of PM10 monitoring presented in suggest that the PM10 objectives are

being met in Brent, even close to busy roadsides. It is therefore anticipated that there

will not be any exceedences of the PM10 objectives anywhere in the assessment study

area.



5.3.4.13 Background Concentrations

5.3.4.14 National Background Pollution Maps

5.3.4.15 In addition to these locally measured concentrations, estimated background

concentrations in the study area have been determined for 2012 and the opening year

2018 (Table 5.5). In the case of nitrogen oxides and nitrogen dioxide, two sets of

future-year backgrounds are presented to take into account uncertainty in future year

vehicle emission factors. The derivation of background concentrations is described in

Appendix D. The background concentrations are all below the objectives.

5.3.4.16 It should be noted that the mapped background nitrogen dioxide and PM10

concentrations are broadly consistent with the measured concentrations at St Mary’s

Primary School as presented in Table 5.3 and Table 5.4.

Table 5.5: Estimated Annual Mean Background Pollutant Concentrations in 2013 and

2018 (µg/m3)

Year NOx NO2 PM10 PM2.5

2013 a 64.0 –

70.7

34.9 –

37.7

19.8 –

20.7

14.0 –

14.5

2018 – Without Reductions in

Traffic Emissions b

59.9 –

66.6

33.3 –

36.1

n/a n/a

2018 – With Reductions in Traffic

Emissions c

51.6 –

56.3

29.4 –

31.5

18.8 –

19.6

12.9 –

13.4

Objectives - 40 40 25

n/a = not applicable

a This assumes that road vehicle emission factors in 2013 remain the same as in 2010

(See Appendix D).

b This assumes that road vehicle emission factors in 2018 remain the same as in 2010.

c This assumes that road vehicle emission factors reduce between 2013 and 2018 at

the current ‘official’ rates.



5.3.4.17 Baseline Dispersion Model Results

5.3.4.18 Baseline concentrations of nitrogen dioxide, PM10 and PM2.5 have been modelled at

each of the existing receptor locations (see Figure 5.3 and Table 5.2).

5.3.4.19 The results, which cover both existing (2012) and future year (2018) baseline (Without

Scheme), are set out in Table 5.6 and Table 5.7. The future baseline for nitrogen

dioxide covers the two scenarios: with the official reductions in vehicle emission factors

and without these reductions. The modelled road components of nitrogen oxides

concentrations have been adjusted by a factor of 4.691, which was derived during the

model verification process, and the total NO2 has been adjusted by a secondary

verification factor of 1.001 (see Appendix D for details of the model verification).

Table 5.6: Modelled Annual Mean Baseline Concentrations of Nitrogen Dioxide (µg/m3)

at Existing Receptors

Receptor 2013 2018 Without Scheme

With ‘Official’

Emissions Reduction a

Without Emissions

Reduction b

Receptor 1 39.0 32.5 37.5

Receptor 2 39.0 32.5 37.5

Receptor 3 39.1 32.5 37.6

Receptor 4 39.6 32.9 38.1

Receptor 5 39.5 32.8 38.1

Receptor 6 39.8 33.0 38.3

Receptor 7 39.6 32.9 38.2

Receptor 8 39.8 33.1 38.4

Receptor 9 37.3 31.2 35.8

Receptor 10 37.6 31.4 36.1

Receptor 11 38.5 32.1 37.1

Receptor 12 38.2 31.8 36.7

Receptor 13 39.4 32.7 38.0

Receptor 14 41.4 34.1 40.1

Receptor 15 43.9 36.0 42.9

Receptor 16 51.3 41.4 50.7

Receptor 17 56.6 45.4 56.5



Receptor 18 61.2 48.6 61.7

Receptor 19 43.4 35.5 42.5

Receptor 20 41.4 34.0 40.3

Receptor 21 58.0 45.6 58.5

Receptor 22 61.5 48.0 62.0

Receptor 23 58.9 45.8 59.2

Receptor 24 77.6 59.7 79.4

Receptor 25 68.5 54.0 69.5

Receptor 26 52.4 41.9 52.2

Receptor 27 58.1 46.1 58.5

Receptor 28 84.7 66.7 86.6

Receptor 29 53.3 43.0 53.1

Receptor 30 75.6 59.3 77.1

Receptor 31 71.4 56.6 72.4

Receptor 32 78.8 62.7 79.7

Receptor 33 77.4 61.5 78.3

Receptor 34 68.9 56.2 68.3

Receptor 35 65.1 53.1 64.4

Receptor 36 75.1 61.2 74.7

Receptor 37 65.0 53.1 64.4

Receptor 38 58.3 47.6 57.5

Receptor 39 51.6 42.1 50.6

Receptor 40 49.5 40.4 48.5

Objective 40

a This assumes that road vehicle emission factors reduce between 2013 and 2018 at





Table 5.7: Modelled Baseline Concentrations of PM10 and PM2.5 at Existing Receptors

Receptor PM10 a PM2.5

Annual Mean (g/m3) No. Days >50 µg/m3 Annual Mean (g/m3)

2013 2018

Without

Scheme

2013 2018

Without

Scheme

2013 2018

Without

Scheme

Receptor 1 20.9 19.8 5 3 14.7 13.5

Receptor 2 20.9 19.8 5 3 14.7 13.5

Receptor 3 20.9 19.8 5 3 14.7 13.5

Receptor 4 21.0 19.9 5 3 14.7 13.6

Receptor 5 21.0 19.9 5 3 14.7 13.6

Receptor 6 21.0 19.9 5 3 14.7 13.6

Receptor 7 21.0 19.9 5 3 14.7 13.6

Receptor 8 21.0 19.9 5 3 14.7 13.6

Receptor 9 20.1 19.0 4 2 14.2 13.1

Receptor 10 20.2 19.1 4 2 14.2 13.1

Receptor 11 20.3 19.2 4 2 14.3 13.2

Receptor 12 20.2 19.1 4 2 14.3 13.1

Receptor 13 20.4 19.2 4 3 14.3 13.2

Receptor 14 20.6 19.4 4 3 14.5 13.3

Receptor 15 20.9 19.7 5 3 14.7 13.5

Receptor 16 21.8 20.5 6 4 15.3 13.9

Receptor 17 22.5 21.0 7 5 15.7 14.3

Receptor 18 22.5 21.0 7 5 15.7 14.3

Receptor 19 20.7 19.5 4 3 14.6 13.4

Receptor 20 20.5 19.4 4 3 14.4 13.3

Receptor 21 22.5 21.0 7 5 15.7 14.2

Receptor 22 23.3 21.7 9 6 16.1 14.6

Receptor 23 23.2 21.7 8 6 16.0 14.6



Receptor 24 26.1 24.1 15 10 17.9 16.0

Receptor 25 23.8 22.1 10 6 16.4 14.8

Receptor 26 21.6 20.3 6 4 15.0 13.8

Receptor 27 22.3 20.9 7 5 15.5 14.1

Receptor 28 25.0 23.1 12 8 17.3 15.4

Receptor 29 21.7 20.4 6 4 15.1 13.8

Receptor 30 24.1 22.3 10 7 16.8 15.1

Receptor 31 24.0 22.2 10 7 16.7 15.0

Receptor 32 25.5 23.5 14 9 17.7 15.8

Receptor 33 25.6 23.7 14 9 17.7 15.8

Receptor 34 24.7 23.0 12 8 17.2 15.4

Receptor 35 24.1 22.5 10 7 16.8 15.1

Receptor 36 25.5 23.6 14 9 17.7 15.8

Receptor 37 23.9 22.3 10 7 16.7 15.0

Receptor 38 23.0 21.5 8 6 16.1 14.6

Receptor 39 22.3 21.0 7 5 15.6 14.2

Receptor 40 22.1 20.8 6 4 15.4 14.1

Objective 40 40 35 35 25 25

a The numbers of days with PM10 concentrations greater than 50 g/m3 have been

estimated from the relationship with the annual mean concentration described in

LAQM.TG(09) (Defra, 2009).

5.3.4.20 2013 Baseline

5.3.4.21 The predicted annual mean concentrations of nitrogen dioxide exceed the objective at

most receptor locations within the study area in 2013. The maximum predicted

baseline nitrogen dioxide concentration is 84.7 µg/m3 at Receptor 28 at the junction of

Chamberlayne Road and Banister Road. Although this concentration is over twice the

annual mean objective for nitrogen dioxide, it is broadly in line with the roadside

monitored nitrogen dioxide concentrations presented in Table 5.3.

5.3.4.22 Those receptors where the annual mean objective is predicted to be met are all along

Albert Road, and Canterbury Road. These roads have no available baseline traffic

data, and therefore these concentrations may be slightly underestimated. This is taken

into consideration in the conclusions of this assessment.



5.3.4.23 The baseline PM10 and PM2.5 in 2013 are all well below the objectives. This is

consistent with PM10 monitoring in Brent, which does not identify any exceedences of

the PM10 objectives, even close to busy roadsides (Table 5.4).

5.3.4.24 2018 Baseline With ‘Official’ Emission Reduction

5.3.4.25 The predicted annual mean concentrations of nitrogen dioxide remain above the

objective at the majority of receptor locations in 2018 assuming that vehicle emissions

reduce in line with Defra predictions.

5.3.4.26 All of the predictions for PM10 and PM2.5 are well below the objectives.

5.3.4.27 2018 Baseline Without Emission Reduction

5.3.4.28 The predicted annual mean concentrations of nitrogen dioxide remain above the

objective at the majority of receptor locations in 2018 assuming that vehicle emissions

stay constant between 2013 and 2018.

5.3.4.29 These results are consistent with the conclusions of Brent Council in the outcome of its

air quality review and assessment work.

5.3.5 Impact Assessment – Site 18

5.3.5.1 The following section of the report examines the potetnail air quality impacts

associated with the construction and operation of the HS2 ventilation shaft and

automatic transformer at Site 18. Section 5.3.6 covers the potential air quality impacts

of construction and operation of the shaft and transformer at Canterbury Works.


5.3.5.3 Predicted annual mean concentrations of nitrogen dioxide, PM10 and PM2.5, as well as

days with PM10 >50 µg/m3, are set out in Table 5.8, Table 5.9 and Table 5.10 for both

the “Without Scheme” and “With Scheme” scenarios. These tables also describe the

impacts at each receptor using the impact descriptors given in Appendix B. For

nitrogen dioxide, results are presented for two scenarios to reflect current uncertainty in

Defra’s future-year vehicle emission factors.

5.3.5.4 Nitrogen Dioxide With ‘Official’ Emissions Reduction

5.3.5.5 Assuming vehicle emissions decrease in line with Defra predictions between 2013 and

2018, there remain widespread exceedences of the annual mean nitrogen dioxide

objective throughout the study area. Emissions from construction traffic generated by

the scheme are predicted to increase annual mean nitrogen dioxide concentrations by

an imperceptible amount, and therefore based on the criteria set out in Appendix B, the

air quality impacts at all receptors are negligible.

5.3.5.6 Nitrogen Dioxide Without Emissions Reduction

5.3.5.7 Assuming no reduction in emissions, the annual mean nitrogen dioxide concentrations

are above the objective at the majority of receptors. . Emissions from construction

traffic generated by the scheme are predicted to increase annual mean nitrogen

dioxide concentrations by an imperceptible amount, and therefore based on the criteria

set out in Appendix B, the air quality impacts at all receptors are negligible.



5.3.5.8 PM10 and PM2.5

5.3.5.9 The annual mean PM10 and PM2.5 concentrations are well below the objectives at all

receptors, with or without the scheme, as are the numbers of days with PM10

concentrations above 50 µg/m3.

5.3.5.10 The magnitudes of change are imperceptible at all receptors. Coupled with the

concentrations all being well below the objective, the impacts are thus described as

negligible.

Table 5.8: Predicted Impacts on Annual Mean Nitrogen Dioxide Concentrations in 2018

(µg/m3)

Receptor With ‘Official’ Emissions

Reduction a

Without Emissions Reduction b

Without

Schem

e

With

Schem

e

Impact

Descriptor

Without

Scheme

With

Scheme

Impact

Descriptor

Receptor 1 32.5 32.5 Negligible 37.5 37.5 Negligible










































Objective 40 - 40 -






Table 5.9: Predicted PM10 Impacts in 2018 (µg/m3)

Receptor Annual Mean (µg/m3) Days with PM10 > 50 g/m3 a

Without

Schem

e

With

Scheme

Impact

Descriptor

Without

Scheme

With

Scheme

Impact

Descriptor

Receptor 1 19.8 19.8 Negligible 3 3 Negligible










































Objective 40 - 35 -




Table 5.10: Predicted PM2.5 Impacts in 2018 (µg/m3)

Receptor Annual Mean (µg/m3)

Without Scheme With Scheme Impact Descriptor

Receptor 1 13.5 13.5 Negligible














Objective 25 -


5.3.5.12 The construction works will give rise to a risk of dust impacts during demolition,

earthworks and construction, as well as from trackout of dust and dirt by vehicles onto

the public highway. It should be noted that in this assessment of dust impacts during

construction works, the construction activities only involve the erection of structures,

site surfacing and site fit-out. Other activities undertaken during the construction

period such as vent shaft excavation are classed as either earthworks or demolition.

5.3.5.13 The construction will take place over a 7-year period, although this will involve a 2-year

break in works following the excavation of the vent shaft.

5.3.5.14 Potential Dust Emission Magnitude

5.3.5.15 There site preparation for Site 18 will involve the demolition of a number of buildings

and structures at the site, including the existing 3-storey TfL depot and the former

Keniston Press printer’s buildings. Based on the example definitions set out in Table

A.1, the dust emission class for demolition is considered to be medium.

5.3.5.16 Using the National Environment Research Council’s Soil Portal website (National

Environment Research Council, 2014), the characteristics of the soil at the

development site have been defined. These are detailed in Table 5.11. Overall, it is

considered that, when dry, this soil has the potential to be moderately dusty.

Table 5.11: Summary of Soil Characteristics

Category Record

Soil layer thickness Deep

Grain Size (and Soil Parent Material) Argillaceousa

European Soil Bureau Description Prequaternary Marine/Estuarine Sand and Silt

Soil Group Medium to Light (Silty) to Heavy

Soil Texture Clay to Silt



a clay-like.

5.3.5.17 Earthworks at the site will form a considerable part of the construction period. The

principal earthwork activity involves the excavation of the vent shaft, which is to

measure approximately 43 m by 19 m in size. The base of the shaft will extend to a

depth below ground level of 41 m, with the foundations extending to 51 m below

ground. This incorporates as long period of excavation, with removal of very large

volumes of subsoil, which will be removed from site by road. The excavation of the

vent shaft represents a significant potential to generate dust, especially during dry

conditions. The subsoil characteristics at Site 18 have been identified in paragraph

5.3.5.16 as having the potential to be moderately dusty. Based on the example

definitions set out in Table A.1, the dust emission class for earthworks is considered to

be large.

5.3.5.18 The construction activities at Site 18 will involve the construction of the vent shaft head

house, which will be a predominantly concrete structure measuring 43 m by 19 m and

will be 9.5 m high. There will also be an auto transformer station constructed on the

site, with dimensions of approximately 33 m long, 16 m wide and 5 m high. The

remainder of the site will be hard standing to allow for access and egress from the

tunnel. Dust will arise during construction activities from vehicles travelling over

unpaved ground, the handling and storage of dusty materials, and from the cutting of

concrete. Based on the example definitions set out in Table A.1, the dust emission

class for construction is considered to be medium.

5.3.5.19 The number of vehicles accessing the site, which may track out dust and dirt will vary

considerably throughout the construction period. As stated in Section 2, during typical

peak activities, there will be approximately 108 vehicle trips per day (54 arrivals, 54

departures), of which 38 will be HGVs. During the concrete pour for the vent shaft

foundations, it is estimated that there may be as many as 388 vehicle trips in any one

day, including 328 HGV movements (164 arrivals and departures). Based on the

example definitions set out in Table A.1, the dust emission class for trackout is

considered to be large.

5.3.5.20 Table 5.12 summarises the dust emission magnitude for the proposed development.

Table 5.12: Summary of Dust Emission Magnitude

Source Dust Emission Magnitude

Demolition Medium

Earthworks Large

Construction Medium

Trackout Large

5.3.5.21 Sensitivity of the Area

5.3.5.22 This assessment step combines the sensitivity of individual receptors to dust effects,

with the number of receptors in the area and their proximity to the site. It also



considers additional site-specific factors such as topography and screening, and in the

case of sensitivity to human health effects, baseline PM10 concentrations.

5.3.5.23 Sensitivity of the Area to Effects from Dust Soiling

5.3.5.24 The IAQM guidance explains that residential properties are ‘high’ sensitivity receptors

to dust soiling, while the shops and commercial premises are considered is ‘medium’

sensitivity receptors (Table A.2). There are between 10 and 100 residential dwellings

(apartment buildings and flats are judged to classify as >1 dwelling) within 20 m of the

Site 18 boundary, as well as a number of shops and small business premises. Using

the matrix set out in Table B.3, the area surrounding the onsite works is of ‘high’

sensitivity to dust soiling. Table 5.12 shows that dust emission magnitude for trackout

is ‘large’ and Table A.3 thus explains that there is a risk of material being tracked

500 m from the site exit. There are between 10 and 100 residential dwellings within 20

m of the roads along which material could be tracked, and Table A.3 thus indicates that

the area is of ‘high’ sensitivity to dust soiling due to trackout. Taking these points into

account, it is judged that the area surrounding the onsite works is of ‘high’ sensitivity to

dust soiling, and the area surrounding roads along which material may be tracked from

the site is also of ‘high’ sensitivity (Table 5.13).

5.3.5.25 Sensitivity of the Area to any Human Health Effects

5.3.5.26 Residential properties are also classified as being of ‘high’ sensitivity to human health

effects. The IAQM matrix in Table A.4 requires information on the baseline annual

mean PM10 concentration in the area. Receptors 30 – 33 are all at Premier Corner,

adjacent to Site 18 (Figure 5.1). The maximum predicted baseline PM10 concentration

at these receptors is 25.6 µg/m3 (Table 5.7), and this value has been used. Using the

matrix in Table A.4, the area surrounding the onsite works is of ‘high’ sensitivity to

human health effects, as is the area surrounding roads along which material may be

tracked from the site (Table 5.13).

Table 5.13: Summary of the Area Sensitivity

Effects Associated With: Sensitivity of the Surrounding Area

On-site Works Trackout

Dust Soiling High Sensitivity High Sensitivity

Human Health High Sensitivity High Sensitivity

5.3.5.27 Risk and Significance

5.3.5.28 The dust emission magnitudes in Table 5.12 have been combined with the sensitivities

of the area in Table 5.13 using the matrix in Table A.6 in Appendix A, in order to assign

a risk category to each activity. The resulting risk categories for the four construction

activities, without mitigation, are set out in Table 5.14. These risk categories have been

used to determine the appropriate level of mitigation as set out in Section 5.3.7.



Table 5.14: Summary of Risk of Impacts Without Mitigation

Source Dust Soiling Human Health

Demolition Medium Risk High Risk

Earthworks High Risk High Risk

Construction Medium Risk High Risk

Trackout High Risk High Risk

5.3.5.29 The IAQM does not provide a method for assessing the significance of effects before

mitigation, and advises that pre-mitigation significance should not be determined. With

appropriate mitigation in place, the IAQM guidance is clear that the residual effect will

normally not be significant (Institute of Air Quality Management, 2014).

5.3.5.30 The IAQM guidance recognises that, even with a rigorous dust management plan in

place, it is not possible to guarantee that the dust mitigation measures will be effective

all of the time, for instance under adverse weather conditions. The local community

may therefore experience occasional, short-term dust annoyance. The scale of this

would not normally be considered sufficient to change the conclusion that the effects

will not be significant.

5.3.5.31 Uncertainty in Road Traffic Modelling Predictions

5.3.5.32 There are many components that contribute to the uncertainty of modelling predictions.

The model used in this assessment is dependent upon the traffic data that have been

input, which will have inherent uncertainties associated with them. There are then

additional uncertainties, as the model is required to simplify real-world conditions into a

series of algorithms. An important stage in the process is model verification, which

involves comparing the model output with measured concentrations (see Appendix D).

Because the model has been verified and adjusted, there can be reasonable

confidence in the prediction of current year (2013) concentrations.

5.3.5.33 Predicting pollutant concentrations in a future year will always be subject to greater

uncertainty. For obvious reasons, the model cannot be verified in the future, and it is

necessary to rely on a series of projections provided by DfT and Defra as to what will

happen to traffic volumes, background pollutant concentrations, and vehicle emissions.

A disparity between the road transport emission projections and measured annual

mean concentrations of nitrogen oxides and nitrogen dioxide has been identified by

Defra (Carslaw, Beevers, Westmoreland, & Williams, 2011). This is evident across the

UK, although the effect appears to be greatest in inner London; there is also

considerable inter-site variation. Whilst the emission projections suggested that both

annual mean nitrogen oxides and nitrogen dioxide concentrations should have fallen

by around 15-25% over the past 6 to 8 years, at many monitoring sites levels have

remained relatively stable, or have even shown a slight increase. This pattern is

mirrored in the monitoring data assembled for this study, as set out in Table 5.3.

5.3.5.34 The reason for the disparity is thought to relate to the on-road performance of modern

diesel vehicles. New vehicles registered in the UK have to meet progressively tighter



European type approval emissions categories, referred to as "Euro" standards. While

the nitrogen oxides emissions from newer vehicles should be lower than those from

equivalent older vehicles, the on-road performance of some modern diesel vehicles is

often no better than that of earlier models (Carslaw, Beevers, Westmoreland, &

Williams, 2011). The best current evidence is that, where previous standards have had

limited on-road success, the ‘Euro VI’ and ‘Euro 6’ standards that new vehicles will

have to comply with from 2013/152 will achieve the expected on-road improvements,

as, for the first time, they will require compliance with the World Harmonized Test

Cycle, which better represents real-world driving conditions3 and includes a separate

slow-speed cycle for heavy duty vehicles.

5.3.5.35 As noted above, the new forecast reductions in nitrogen oxides emissions may still be

optimistic in the near-term. To account for this uncertainty, a sensitivity test has been

conducted assuming that the future (2018) road traffic emissions per vehicle are

unchanged from 2013 values. The predictions within this sensitivity test are likely to be

over-pessimistic, as new, lower-emission Euro VI and Euro 6 vehicles will be on the

road from 2013/15; according to Defra’s Emission Factors Toolkit (Defra, 2014a), by

2018 it is forecast that there will be a roughly 50-70% penetration of Euro VI HDVs and

a roughly 35-40% penetration of Euro 6 LDVs. These new vehicles are expected to

deliver real on-road reductions in nitrogen oxides emissions.

5.3.5.36 Significance of Operational Air Quality Impacts

5.3.5.37 The operational air quality impacts are judged to be insignificant. This professional

judgement is made in accordance with the methodology set out in Paragraph 5.6.2.5

(Appendix B), taking into account the factors set out in Table B.3, and also taking into

account the uncertainty over future projections of traffic-related nitrogen dioxide

concentrations, which may not decline as rapidly as expected.

5.3.5.38 More specifically, the judgement that the air quality impacts will be insignificant takes

account of the assessment that emissions from the development-related construction

traffic will lead to imperceptible changes in roadside pollutant concentrations and all of

the predicted air quality impacts are negligible.

Table 5.15: Factors Taken into Account in Determining the Overall Significance of the

Scheme on Local Air Quality

Factors Outcome of Assessment

Number of people affected by increases

and/or decreases in concentrations and a

judgement on the overall balance.

Construction traffic emissions will to

imperceptible changes in pollutant

concentrations at all relevant receptor

locations.

The magnitude of the changes and the Emissions from construction traffic are

2 Euro VI refers to heavy duty vehicles, while Euro 6 refers to light duty vehicles. The timings for meeting the

standards vary with vehicle type and whether the vehicle is a new model or existing model. 3

The test cycle for real-world emissions for Euro 6 vehicles will not be implemented until about 2017. However, there is still expected to be a

substantial improvement in NOx emissions from Euro 6 vehicles (as compared with Euro 5) from 2015 onwards.



descriptions of the impacts at the

receptors.

predicted to lead to negligible air quality

impacts at all receptor locations.

Whether or not an exceedence of an

objective is predicted to arise in the study

area where none existed before or an

exceedence area is substantially

increased.

No new areas of exceedence of the

objective are predicted.

Uncertainty, including the extent to which

worst-case assumptions have been

made.

The inclusion of the two scenarios for

nitrogen dioxide covers the uncertainty over

vehicle emission factors.

Whether or not the study area exceeds

an objective and this exceedence is

removed or the exceedence area is

reduced.

Baseline nitrogen dioxide concentrations

exceed the annual mean objective by a

substantial margin throughout the study

area, regardless of whether or not Defra’s

predicted reductions in road traffic

emissions materialise by 2018 or not. No

exceedences will be removed as a result of

Site 18 construction traffic.

5.3.6 Impact Assessment – Canterbury Works

5.3.6.1 Road Traffic Impacts

5.3.6.2 Predicted annual mean concentrations of nitrogen dioxide, PM10 and PM2.5, as well as

days with PM10 >50 µg/m3, are set out in Table 5.16, Table 5.17 and Table 5.18 for

both the “Without Scheme” and “With Scheme” scenarios. These tables also describe

the impacts at each receptor using the impact descriptors given in Appendix B. For

nitrogen dioxide, results are presented for two scenarios to reflect current uncertainty in

Defra’s future-year vehicle emission factors.

5.3.6.3 Nitrogen Dioxide With ‘Official’ Emissions Reduction

5.3.6.4 Assuming vehicle emissions decrease in line with Defra predictions between 2013 and

2018, there remain widespread exceedences of the annual mean nitrogen dioxide

objective throughout the study area. Emissions from construction traffic generated by

the scheme are predicted to increase annual mean nitrogen dioxide concentrations by

an imperceptible amount, and therefore based on the criteria set out in Appendix B, the

air quality impacts at all receptors are negligible.

5.3.6.5 Nitrogen Dioxide Without Emissions Reduction

5.3.6.6 Assuming no reduction in emissions, the annual mean nitrogen dioxide concentrations

are above the objective at the majority of receptors. Emissions from construction traffic

generated by the scheme are predicted to increase annual mean nitrogen dioxide

concentrations by an imperceptible amount at all but one receptor (Receptor 10) where

a small increase in nitrogen dioxide concentrations is predicted. Based on the criteria



set out in Appendix B, the air quality impacts at all receptors are negligible, apart from

Receptor 10, which is predicted to experience a slight adverse impact.

5.3.6.7 Receptor 10 is located close to the kerbside of Albert Road, where it will experience

the greatest influence of emissions from Canterbury Works construction traffic; other

receptors adjacent to Albert Road and Canterbury Road are set sufficiently far back

from the road to ensure dispersion is adequate to lead to imperceptible changes in

nitrogen dioxide concentrations. Despite the predicted slight adverse impact, the

annual mean nitrogen dioxide objective is predicted to be met at this receptor with or

without the Canterbury Works site in use for vent shaft construction.

5.3.6.8 PM10 and PM2.5

5.3.6.9 The annual mean PM10 and PM2.5 concentrations are well below the objectives at all

receptors, with or without the scheme, as are the numbers of days with PM10

concentrations above 50 µg/m3.

5.3.6.10 The magnitudes of change are imperceptible at all receptors. Coupled with the

concentrations all being well below the objective, the impacts are thus described as

negligible.

Table 5.16: Predicted Impacts on Annual Mean Nitrogen Dioxide Concentrations in 2018

(µg/m3)

Receptor With ‘Official’ Emissions Reductiona Without Emissions Reductionb

Without

Schem

e

With

Schem

e

Impact

Descriptor

Without

Scheme

With

Scheme

Impact

Descriptor










Receptor 10 31.4 31.6 Negligible 36.1 36.5 Slight Adverse





Objective 40 - 40 -




Table 5.17: Predicted PM10 Impacts in 2018 (µg/m3)

Receptor Annual Mean (µg/m3) Days with PM10 > 50 g/m3 a

Without

Scheme

With

Scheme

Impact

Descriptor

Without

Scheme

With

Scheme

Impact

Descriptor











































Objective 40 - 35 -




Table 5.18: Predicted PM2.5 Impacts in 2018 (µg/m3)

Receptor Annual Mean (µg/m3)

Without Scheme With Scheme Impact Descriptor















Objective 25 -

5.3.6.11 Construction Phase Impacts

5.3.6.12 The construction works will give rise to a risk of dust impacts during demolition,

earthworks and construction, as well as from trackout of dust and dirt by vehicles onto

the public highway. The construction works carried out at Canterbury Works will be the

same as those described at Site 18.

5.3.6.13 Potential Dust Emission Magnitude

5.3.6.14 The site preparation for the Canterbury Works site will involve the demolition of some

small, single-storey structures located to the rear of Canterbury House. Canterbury

House itself will not be demolished. Based on the example definitions set out in Table

A.1, the dust emission class for demolition is considered to be small.

5.3.6.15 Using the National Environment Research Council’s Soil Portal website (National

Environment Research Council, 2014), the characteristics of the soil at the

development site have been defined. These are detailed in Table 5.19. Overall, it is

considered that, when dry, this soil has the potential to be moderately dusty.

Table 5.19: Summary of Soil Characteristics

Category Record

Soil layer thickness Deep

Grain Size (and Soil Parent Material) Argillaceousa

European Soil Bureau Description Prequaternary Marine/Estuarine Sand and Silt



Soil Group Medium to Light (Silty) to Heavy

Soil Texture Clay to Silt

a clay-like.

5.3.6.16 Earthworks at the site will form a considerable part of the construction period, as

discussed in paragraph 5.3.5.17. The subsoil characteristics at the Canterbury Works

have been identified in Table 5.19 as having the potential to be moderately dusty.

Based on the example definitions set out in Table A.1, the dust emission class for

earthworks is considered to be large.

5.3.6.17 Construction activities at the Canterbury Works site will involve the construction of the

vent shaft head house and auto-transformer station and areas of hard standing (see

paragraph 5.3.5.18). Dust will arise during construction activities from vehicles

travelling over unpaved ground, the handling and storage of dusty materials, and from

the cutting of concrete. Based on the example definitions set out in Table A.1, the dust

emission class for construction is considered to be medium.

5.3.6.18 The number of vehicles accessing the site, which may track out dust and dirt will vary

considerably throughout the construction period. During typical peak activities, there

will be approximately 108 vehicle trips per day (54 arrivals, 54 departures), of which 38

will be HGVs. During the concrete pour for the vent shaft foundations, it is estimated

that there may be as many as 388 vehicle trips in any one day, including 328 HGV

movements (164 arrivals and departures). Based on the example definitions set out in

Table A.1, the dust emission class for trackout is considered to be large.

5.3.6.19 Table 5.20 summarises the dust emission magnitude for the proposed development.

Table 5.20: Summary of Dust Emission Magnitude

Source Dust Emission Magnitude

Demolition Small

Earthworks Large

Construction Medium

Trackout Large

5.3.6.20 Sensitivity of the Area

5.3.6.21 This assessment step combines the sensitivity of individual receptors to dust effects,

with the number of receptors in the area and their proximity to the site. It also

considers additional site-specific factors such as topography and screening, and in the

case of sensitivity to human health effects, baseline PM10 concentrations

5.3.6.22 Sensitivity of the Area to Effects from Dust Soiling

5.3.6.23 The IAQM guidance explains that residential properties and schools are ‘high’

sensitivity receptors to dust soiling (Table A.2). There are over 100 sensitive receptors

within 20 m of the Canterbury Works site boundary, including residential dwellings and



St Mary’s Catholic Primary School, which is located immediately to the east of the

Canterbury Works site. It should be noted that the guidance advises that apartment

blocks and schools are judged to classify as multiple sensitive receptors depending on

the likely number of occupants. Using the matrix set out in Table A.3, the area

surrounding the onsite works is of ‘high’ sensitivity to dust soiling. Table 5.20 shows

that dust emission magnitude for trackout is ‘large’ and Table A.3 thus explains that

there is a risk of material being tracked 500 m from the site exit. There are over 100

residential dwellings within 20 m of the roads along which material could be tracked

(principally along Canterbury Terrace and Albert Road), and Table A.3 thus indicates

that the area is of ‘high’ sensitivity to dust soiling due to trackout. Taking these points

into account, it is judged that the area surrounding the onsite works is of ‘high’

sensitivity to dust soiling, and the area surrounding roads along which material may be

tracked from the site is also of ‘high’ sensitivity (Table 5.21).

5.3.6.24 Sensitivity of the Area to any Human Health Effects

5.3.6.25 Residential properties are also classified as being of ‘high’ sensitivity to human health

effects. The IAQM matrix in Table A.4 requires information on the baseline annual

mean PM10 concentration in the area. Receptors 1 – 10 are in close proximity to the

Canterbury Works site (Figure 5.2). The maximum predicted baseline PM10

concentration at these receptors is 21.0 µg/m3 (Table 5.7), and this value has been

used. Using the matrix in Table A.4, the area surrounding the onsite works is of

‘medium’ sensitivity to human health effects, as is the area surrounding roads along

which material may be tracked from the site (Table 5.13).

Table 5.21: Summary of the Area Sensitivity

Effects Associated With: Sensitivity of the Surrounding Area

On-site Works Trackout

Dust Soiling High Sensitivity High Sensitivity

Human Health Medium Sensitivity Medium Sensitivity

5.3.6.26 Risk and Significance

5.3.6.27 The dust emission magnitudes in Table 5.20 have been combined with the sensitivities

of the area in Table 5.21 using the matrix in Table A.6 in Appendix A, in order to assign

a risk category to each activity. The resulting risk categories for the four construction

activities, without mitigation, are set out in Table 5.22. These risk categories have been

used to determine the appropriate level of mitigation as set out in Section 5.3.7.

Table 5.22: Summary of Risk of Impacts Without Mitigation

Source Dust Soiling Human Health

Demolition Medium Risk Low Risk



Earthworks High Risk Medium Risk

Construction Medium Risk Medium Risk

Trackout High Risk Medium Risk











5.3.6.30 Uncertainty in Road Traffic Modelling Predictions

5.3.6.31 As discussed in paragraph 5.3.5.32, there are inherent uncertainties associated with

dispersion modelling of road traffic emissions. The level of uncertainty for the

assessment of Canterbury Works is the same as that for Site 18 and therefore the

results of the modelling are directly comparable, irrespective of any residual uncertainty

following model verification and future year sensitivity testing.

5.3.6.32 Significance of Operational Air Quality Impacts

5.3.6.33 The operational air quality impacts are judged to be insignificant. This professional

judgement is made in accordance with the methodology set out in Paragraph 5.6.2.5

(Appendix B), taking into account the factors set out in Table B.2, and also taking into

account the uncertainty over future projections of traffic-related nitrogen dioxide

concentrations, which may not decline as rapidly as expected.

5.3.6.34 More specifically, the judgement that the air quality impacts will be insignificant takes

account of the assessment that the predicted air quality impacts are negligible at all

receptor locations, with the exception of Receptor 10 at Albert Road, where slight

adverse impacts are predicted in the ‘without emissions reduction’ scenario. Given the

conservative nature of this scenario and the fact that the annual mean objective is not

predicted to be exceeded at this receptor, with or without Canterbury Works under

construction, it is judged that the impact at this receptor is not significant.

Table 5. 23: Factors Taken into Account in Determining the Overall Significance of the

Scheme on Local Air Quality

Factors Outcome of Assessment

Number of people affected by increases

and/or decreases in concentrations and a


Construction traffic emissions will to

imperceptible changes in pollutant

concentrations at all relevant receptor



locations except Receptor 10 in the without

emissions reduction scenario where a small

increase in nitrogen dioxide concentrations

are predicted.

The magnitude of the changes and the

descriptions of the impacts at the

receptors.

Emissions from construction traffic are

predicted to lead to negligible air quality

impacts at all receptor locations except

Receptor 10 in the without emissions

reduction scenario where a slight adverse

impact with respect to nitrogen dioxide

concentrations is predicted.

Whether or not an exceedence of an

objective is predicted to arise in the study

area where none existed before or an

exceedence area is substantially

increased.

No new areas of exceedence of the

objective are predicted.

Uncertainty, including the extent to which

worst-case assumptions have been

made.

The inclusion of the two scenarios for

nitrogen dioxide covers the uncertainty over

vehicle emission factors.

Whether or not the study area exceeds

an objective and this exceedence is

removed or the exceedence area is

reduced.

Baseline nitrogen dioxide concentrations

exceed the annual mean objective by a

substantial margin throughout the study

area, regardless of whether or not Defra’s

predicted reductions in road traffic

emissions materialise by 2018 or not. No

exceedences will be removed as a result of

Canterbury Works construction traffic.



5.3.7 Mitigation


5.3.7.2 Site 18

5.3.7.3 Measures to mitigate dust emissions will be required during the construction phase of

the development in order to reduce impacts upon nearby sensitive receptors.

5.3.7.4 Site 18 has been identified as a High Risk site as set out in Table 5.14. The GLA Best

Practice Guidance (GLA, 2006) describes best practice measures that should be

employed, as appropriate, to reduce the impact of a high risk site. However, more

comprehensive guidance has been published by IAQM (Institute of Air Quality

Management, 2014), and on monitoring during demolition and construction (Institute of

Air Quality Management, 2012b). This reflects best practice experience and has been

used, together with the professional experience of the consultant and the findings of

the dust impact assessment, to draw up a set of measures that should be incorporated

into the specification for the works. These measures are described in Appendix E.

5.3.7.5 The mitigation measures should be written into a dust management plan (DMP). The

DMP may be integrated into a Code of Construction Practice or the Construction

Environmental Management Plan, and may require monitoring.

5.3.7.6 Where mitigation measures rely on water, it is expected that only sufficient water will

be applied to damp down the material. There should not be any excess to potentially

contaminate local watercourses.

5.3.7.7 Canterbury Works

5.3.7.8 Measures to mitigate dust emissions will be required during the construction phase of

the development in order to reduce impacts upon nearby sensitive receptors.

5.3.7.9 Canterbury Works has been identified as a Medium to High Risk site as set out in

Table 5.22. The level of mitigation required for Canterbury Works is broadly the same,

although slightly less than for Site 18. The measures described in Appendix E are all

highly recommended for Site 18. In the case of Canterbury Works, the measures are

all highly recommended apart from those highlighted in italic type, which are desirable.


5.3.7.11 The assessment has demonstrated that the scheme will not cause any exceedences of

the air quality objectives in areas where they are not currently exceeded. Mitigation

measures to reduce pollutant emissions from road traffic are principally being delivered

in the longer term by the introduction of more stringent emissions standards, largely via

European legislation. It is not considered necessary to propose further mitigation

measures for this scheme for either Site 18 or Canterbury Works.



5.3.8 Conclusions

5.3.8.1 The potential air quality impacts associated with the construction and operation of a

HS2 tunnel ventilation shaft and auto transformer station at the proposed Site 18

(Salusbury Road) and Canterbury Works (Canterbury Road) sites have been

assessed.

5.3.8.2 In terms of the operational air quality impacts, these have been scoped out of the

assessment as insignificant, as the ventilation shaft is not anticipated to result in any

emissions to air, and the site will require only limited staff attendance during operation,

and therefore the number of vehicle movements generated by the site will be minimal,

and any air quality impacts from road traffic emissions would be insignificant.

5.3.8.3 The assessment has focussed upon the potential air quality impacts of the construction

period, both in terms of emissions from construction traffic moving to and from the site,

as well as the impacts of dust and PM10 from on-site construction activities.

5.3.8.4 The air quality impacts associated with emissions from construction traffic are judged

to be insignificant, regardless of whether Site 18 or Canterbury Works is used as the

chosen site for the ventilation shaft. The use of Canterbury Works has the potential to

expose a greater number of residential properties to an increase in road traffic

emissions (at properties along Albert Road and Canterbury Road); however, the

increases in pollutant concentrations have been demonstrated to be imperceptible and

the resultant air quality impacts are all negligible.

5.3.8.5 The risk of construction dust and PM10 impacts is slightly higher for Site 18 than

Canterbury Works; however, with best practice mitigation measures in place, the

potential air quality impacts from use of either site would be insignificant.



5.4 REFERENCES

The Air Quality (England) Regulations, 2000, Statutory Instrument 928. (2000). HMSO.

The Air Quality (England) (Amendment) Regulations, 2002, Statutory Instrument 3043.

(2002). HMSO.

Directive 2008/50/EC of the European Parliament and of the Council. (2008).

The Air Quality Standards Regulations (No. 1001). (2010). Stationery Office.

National Planning Policy Framework. (2012). DCLG.

Carslaw, D., Beevers, S., Westmoreland, E., & Williams, M. (2011). Trends in NOx and

NO2 emissions and ambient measurements in the UK. Retrieved from uk-

air.defra.gov.uk/reports/cat05/1108251149_110718_AQ0724_Final_report.pdf

DCLG. (2014). Planning Practice Guidance. Retrieved from

http://planningguidance.planningportal.gov.uk/blog/guidance/

Defra. (2007). The Air Quality Strategy for England, Scotland, Wales and Northern

Ireland. Defra.

Defra. (2009). Review & Assessment: Technical Guidance LAQM.TG(09). Defra.

Defra. (2014a). Defra Air Quality Website. Retrieved from http://laqm.defra.gov.uk/

Defra. (2014d). UK Pollutant Release and Transfer Register. Retrieved from

prtr.defra.gov.uk

DfT. (2011). DfT Automatic traffic Counters Table TRA0305-0307. Retrieved from

http://www.dft.gov.uk/pgr/statistics/datatablespublications/roads/traffic

Environment Agency. (2014). ‘what’s in your backyard’. Retrieved from

http://www.environment-agency.gov.uk/homeandleisure/37793.aspx

Environmental Protection UK. (2010). Development Control: Planning for Air Quality.

EPUK.

GLA. (2006). The Control of Dust and Emissions from Construction and Demolition: Best

Practice Guidance. Retrieved from

www.london.gov.uk/mayor/environment/air_quality/construction-dust.jsp

GLA. (2013). London Atmospheric Emissions Inventory (LAEI) 2010.

Institute of Air Quality Management. (2009, Novemeber). Position on the Description of Air

Quality Impacts and the Assessment of their Significance. IAQM.

Institute of Air Quality Management. (2012b). Guidance on Air Quality Monitoring in the

Vicinity of Demolition and Construction Sites. Retrieved from

www.iaqm.co.uk/guidance.html



Institute of Air Quality Management. (2014). Guidance on the Assessment of Dust from

Demolition and Construction.

King's College London. (2014). London Air.

LB of Brent. (2005). Air Quality Action Plan.

London Borough of Brent. (2013). 2013 Air Quality Progress Report.

National Environment Research Council. (2014). NERC Soil Portal. Retrieved from

http://mapapps2.bgs.ac.uk/soilportal/wmsviewer.html



5.5 GLOSSARY

AADT Annual Average Daily Traffic

ADMS-Roads Atmospheric Dispersion Modelling System

AQMA Air Quality Management Area

DCLG Department for Communities and Local Government

Defra Department for Environment, Food and Rural Affairs

DfT Department for Transport

DMP Dust Management Plan

EFT Emissions Factor Toolkit

EPUK Environmental Protection UK

Exceedence A period of time when the concentration of a pollutant is greater

than the appropriate air quality objective. This applies to specified locations

with relevant exposure

HDV Heavy Duty Vehicles (> 3.5 tonnes)

HGV Heavy Goods Vehicle

IAQM Institute of Air Quality Management

LAEI London Atmospheric Emissions Inventory

LAQM Local Air Quality Management

LB London Borough

LDV Light Duty Vehicles (<3.5 tonnes)

μg/m3 Microgrammes per cubic metre

NO Nitric oxide

NO2 Nitrogen dioxide

NOx Nitrogen oxides (taken to be NO2 + NO)

NPPF National Planning Policy Framework

Objectives A nationally defined set of health-based concentrations for nine pollutants,

seven of which are incorporated in Regulations, setting out the extent to

which the standards should be achieved by a defined date. There are also

vegetation-based objectives for sulphur dioxide and nitrogen oxides

PM10 Small airborne particles, more specifically particulate matter less than 10

micrometres in aerodynamic diameter

PM2.5 Small airborne particles less than 2.5 micrometres in aerodynamic diameter

PPG Planning Practice Guidance



Standards A nationally defined set of concentrations for nine pollutants below which

health effects do not occur or are minimal

TEA Triethanolamine – used to absorb nitrogen dioxide



5.6 APPENDICES

5.6.1 APPENDIX A - Construction Dust Assessment Procedure

5.6.1.1 The criteria developed by IAQM divide the activities on construction sites into four types to reflect their different potential impacts. These are:

demolition;

earthworks;

construction; and

trackout.

5.6.1.2 The assessment procedure includes the four steps summarised below:

5.6.1.3 STEP 1: Screen the Need for a Detailed Assessment

An assessment is required where there is a human receptor within 350 m of the

boundary of the site and/or within 50 m of the route(s) used by construction vehicles on

the public highway, up to 500 m from the site entrance(s), or where there is an

ecological receptor within 50 m of the boundary of the site and/or within 50 m of the

route(s) used by construction vehicles on the public highway, up to 500 m from the site

entrance(s).

Where the need for a more detailed assessment is screened out, it can be concluded

that the level of risk is negligible and that any effects will not be significant. No

mitigation measures beyond those required by legislation will be required.

5.6.1.4 STEP 2: Assess the Risk of Dust Impacts

A site is llocated to a risk category based on two factors: the scale and nature

of the works, which determines the potential dust emission magnitude (Step

2A); and

the sensitivity of the area to dust effects (Step 2B).

These two factors are combined in Step 2C, which is to determine the risk of dust

impacts with no mitigation applied. The risk categories assigned to the site may be

different for each of the four potential sources of dust (demolition, earthworks,

construction and trackout).

5.6.1.5 Step 2A – Define the Potential Dust Emission Magnitude

Dust emission magnitude is defined as either ‘Small’, ‘Medium’, or ‘Large’. The IAQM

explains that this classification should be based on professional judgement, but

provides the examples in Table A.1.

Table A.1: Examples of How the Dust Emission Magnitude Class May be Defined

Class Examples ………….

Demolition



Large Total building volume >50,000 m3, potentially dusty construction material (e.g.

concrete), on site crushing and screening, demolition activities >20 m above

ground level

Mediu

m

Total building volume 20,000 m3 – 50,000 m3, potentially dusty construction

material, demolition activities 10-20 m above ground level

Small Total building volume <20,000 m3, construction material with low potential for

dust release (e.g. metal cladding or timber), demolition activities <10 m above

ground, demolition during wetter months

Earthworks

Large Total site area >10,000 m2, potentially dusty soil type (e.g. clay, which will be

prone to suspension when dry to due small particle size), >10 heavy earth

moving vehicles active at any one time, formation of bunds >8 m in height,

total material moved >100,000 tonnes

Mediu

m

Total site area 2,500 m2 – 10,000 m2, moderately dusty soil type (e.g. silt), 5-

10 heavy earth moving vehicles active at any one time, formation of bunds 4 m

– 8 m in height, total material moved 20,000 tonnes – 100,000 tonnes

Small Total site area <2,500 m2, soil type with large grain size (e.g. sand), <5 heavy

earth moving vehicles active at any one time, formation of bunds <4 m in

height, total material moved <10,000 tonnes, earthworks during wetter months

Construction

Large Total building volume >100,000 m3, piling, on site concrete batching;

sandblasting

Mediu

m

Total building volume 25,000 m3 – 100,000 m3, potentially dusty construction

material (e.g. concrete), piling, on site concrete batching

Small Total building volume <25,000 m3, construction material with low potential for

dust release (e.g. metal cladding or timber)

Trackout a

Large >50 HDV (>3.5t) outward movements in any one day, potentially dusty surface

material (e.g. high clay content), unpaved road length >100 m

Mediu

m

10-50 HDV (>3.5t) outward movements in any one day, moderately dusty

surface material (e.g. high clay content), unpaved road length 50 m – 100 m

Small <10 HDV (>3.5t) outward movements in any one day, surface material with

low potential for dust release, unpaved road length <50 m

a These numbers are for vehicles that leave the site after moving over unpaved ground.



5.6.1.6 Step 2B – Define the Sensitivity of the Area

5.6.1.7 The sensitivity of the area is defined taking account of a number of factors:

the specific sensitivities of receptors in the area;

the proximity and number of those receptors;

in the case of PM10, the local background concentration; and

site-specific factors, such as whether there are natural shelters to reduce the

risk of wind-blown dust.

5.6.1.8 The first requirement is to determine the specific sensitivities of local receptors. The

IAQM recommends that this should be based on professional judgment, taking account

of the principles in Table A.2. These receptor sensitivities are then used in the matrices

set out in Table A.3, Table A.4, and Table A.5 to determine the sensitivity of the area.

Finally, the sensitivity of the area is considered in relation to any other site-specific

factors, such as the presence of natural shelters etc., and any required adjustments to

the defined sensitivities are made.

5.6.1.9 Step 2C – Define the Risk of Impacts

5.6.1.10 The dust emission magnitude determined at Step 2A is combined with the sensitivity of

the area determined at Step 2B to determine the risk of impacts with no mitigation

applied. The IAQM provides the matrix in Table A.6 as a method of assigning the level

of risk for each activity.

5.6.1.11 STEP 3: Determine Site-specific Mitigation Requirements

5.6.1.12 The IAQM provides a suite of recommended and desirable mitigation measures which

are organised according to whether the outcome of Step 2 indicates a low, medium, or

high risk. The list provided by the IAQM has been used as the basis for the

requirements set out in Appendix E.

5.6.1.13 STEP 4: Determine Significant Effects











Table A.2: Principles to be Used When Defining Receptor Sensitivities

Class Principles Examples

Sensitivities of People to Dust Soiling Effects

High users can reasonably expect enjoyment of a high level of dwellings,



amenity; or

the appearance, aesthetics or value of their property

would be diminished by soiling; and the people or

property would reasonably be expected a to be present

continuously, or at least regularly for extended periods,

as part of the normal pattern of use of the land

museum and other

culturally important

collections,

medium and long

term car parks and

car showrooms

Mediu

m

users would expect to enjoy a reasonable level of

amenity, but would not reasonably expect to enjoy the

same level of amenity as in their home; or

the appearance, aesthetics or value of their property

could be diminished by soiling; or

the people or property wouldn’t reasonably be expected

to be present here continuously or regularly for extended

periods as part of the normal pattern of use of the land

parks and places

of work

Low the enjoyment of amenity would not reasonably be

expected; or

there is property that would not reasonably be expected

to be diminished in appearance, aesthetics or value by

soiling; or

there is transient exposure, where the people or property

would reasonably be expected to be present only for

limited periods of time as part of the normal pattern of

use of the land

playing fields,

farmland (unless

commercially-

sensitive

horticultural),

footpaths, short

term car parks and

roads

Sensitivities of People to the Health Effects of PM10

High locations where members of the public may be exposed

for eight hours or more in a day

residential

properties,

hospitals, schools

and residential

care homes

Mediu

m

locations where the people exposed are workers, and

where individuals may be exposed for eight hours or

more in a day.

may include office

and shop workers,

but will generally

not include

workers

occupationally

exposed to PM10

Low locations where human exposure is transient public footpaths,

playing fields,

parks and

shopping streets



Sensitivities of Receptors to Ecological Effects

High locations with an international or national designation and

the designated features may be affected by dust soiling;

or

locations where there is a community of a particularly

dust sensitive species

Special Areas of

Conservation with

dust sensitive

features

Mediu

m

locations where there is a particularly important plant

species, where its dust sensitivity is uncertain or

unknown; or

locations with a national designation where the features

may be affected by dust deposition

Sites of Special

Scientific Interest

with dust sensitive

features

Low locations with a local designation where the features may

be affected by dust deposition

Local Nature

Reserves with

dust sensitive

features



Table A.3: Sensitivity of the Area to Effects on People and Property from Dust Soiling 4

Receptor

Sensitivity

Number of

Receptors

Distance from the Source (m)

<20 <50 <100 <350

High >100 High High Medium Low

10-100 High Medium Low Low

1-10 Medium Low Low Low

Medium >1 Low Low Low Low

Low >1 Low Low Low Low

Table A.4:Sensitivity of the Area to Human Health Effects Error! Bookmark not defined.

Receptor

Sensitivity

Annual

Mean PM10

Number of

Receptors


<20 <50 <100 <200 <350

High >32 µg/m3 >100 High High High Mediu

m

Low

10-100 High High Mediu

m

Low Low

1-10 High Mediu

m

Low Low Low

28-32 µg/m3 >100 High High Mediu

m

Low Low

10-100 High Mediu

m

Low Low Low

1-10 High Mediu

m

Low Low Low

24-28 µg/m3 >100 High Mediu

m

Low Low Low

10-100 High Mediu

m

Low Low Low

1-10 Mediu Low Low Low Low

4 For demolition, earthworks and construction, distances are taken either from the dust source or from the boundary

of the site. For trackout, distances are measured from the sides of roads used by construction traffic. Without mitigation, trackout may occur from roads up to 500 m from large sites, 200 m from medium sites and 50 m from small sites, as measured from the site exit. The impact declines with distance from the site, and it is only necessary to consider trackout impacts up to 50 m from the edge of the road.



m

<24 µg/m3 >100 Mediu

m

Low Low Low Low

10-100 Low Low Low Low Low

1-10 Low Low Low Low Low

Medium - >10 High Mediu

m

Low Low Low

- 1-10 Mediu

m

Low Low Low Low

Low - >1 Low Low Low Low Low

Table A.5: Sensitivity of the Area to Ecological Effects Error! Bookmark not defined.

Receptor

Sensitivity


<20 <50

High High Medium

Medium Medium Low

Low Low Low



Table A.6: Defining the Risk of Dust Impacts

Sensitivity of

the Area

Dust Emission Magnitude

Large Medium Small

Demolition

High High Risk Medium Risk Medium Risk

Medium High Risk Medium Risk Low Risk

Low Medium Risk Low Risk Negligible

Earthworks

High High Risk Medium Risk Low Risk

Medium Medium Risk Medium Risk Low Risk

Low Low Risk Low Risk Negligible

Construction


Medium Medium Risk Medium Risk Low Risk


Trackout


Medium Medium Risk Low Risk Negligible




5.6.2 APPENDIX B - Impact Descriptors and Assessment of Significance

5.6.2.1 There is no official guidance in the UK on how to describe the nature of air quality

impacts, nor how to assess their significance. The approach developed by the Institute

of Air Quality Management5 (Institute of Air Quality Management, 2009), and

incorporated in Environmental Protection UK’s guidance document on planning and air

quality (Environmental Protection UK, 2010), has therefore been used. This involves

three distinct stages: the application of descriptors for magnitude of change; the

description of the impact at each sensitive receptor; and then the assessment of overall

significance of the scheme.

5.6.2.2 Impact Descriptors

5.6.2.3 The definition of impact magnitude is solely related to the degree of change in

pollutant concentrations, expressed in microgrammes per cubic metre, but originally

determined as a percentage of the air quality objective. Impact description takes

account of the impact magnitude and of the absolute concentrations and how they

relate to the air quality objectives or other relevant standards. The descriptors for the

magnitude of change due to the scheme are set out Table B.1, while Table B.2 sets out

the impact descriptors. These tables have been designed to assist with describing air

quality impacts at each specific receptor. They apply to the pollutants relevant to this

scheme and the objectives against which they are being assessed.

Table B.1: Definition of Impact Magnitude for Changes in Ambient Pollutant

Concentrations

Magnitude of

Change

Annual Mean

NO2/PM10

No. days with PM10

concentration greater

than 50 µg/m3

Annual Mean PM2.5

Large Increase/decrease

≥4 µg/m3

Increase/decrease

>4 days

Increase/decrease

≥2.5 µg/m3

Medium Increase/decrease

2 - <4 µg/m3

Increase/decrease

3 or 4 days

Increase/decrease

1.25 - <2.5 µg/m3

Small Increase/decrease

0.4 - <2 µg/m3

Increase/decrease

1 or 2 days

Increase/decrease

0.25 - <1.25 µg/m3

Imperceptible Increase/decrease

<0.4 µg/m3

Increase/decrease

<1 day

Increase/decrease

<0.25 µg/m3

5 The IAQM is the professional body for air quality practitioners in the UK.



Table B.2: Air Quality Impact Descriptors for Changes to Annual Mean Nitrogen

Dioxide, PM10 and PM2.5 Concentrations and Changes to Number of Days with PM10

Concentration Greater than 50 µg/m3 at a Receptor a

Absolute Concentration b in Relation to

Objective

Change in Concentration/day c

Small Medium Large

Above Objective d Slight Moderate Substantial

Just Below Objective e Slight Moderate Moderate

Below Objective f Negligible Slight Slight

Well Below Objective g Negligible Negligible Slight

a Criteria have been adapted from the published criteria to remove overlaps at

transitions.

b The ‘Absolute Concentration’ relates to the ‘With-Scheme’ air quality where there is an

increase in concentrations and to the ‘Without-Scheme’ air quality where there is a

decrease in concentrations.

c Where the Impact Magnitude is Imperceptible, then the Impact Description is

Negligible.

d ‘Above’: >40 µg/m3 annual mean NO2 or PM10, >25 µg/m3 annual mean PM2.5, or >35

days with PM10 > 50 µg/m3.

e ‘Just below’: >36 – ≤40 µg/m3 of annual mean NO2 or PM10, >22.5 - ≤25 µg/m3 annual

mean PM2.5, or >32 – ≤35 days with PM10 >50 µg/m3.

f ‘Below’: >30 – ≤36 µg/m3 of annual mean NO2 or PM10, >18.75 - ≤22.5 µg/m3 annual

mean PM2.5, or >26 – ≤32 days with PM10 >50 µg/m3.

g ‘Well below’: ≤30 µg/m3 annual mean NO2 or PM10, ≤18.75 µg/m3 annual mean PM2.5,

or ≤26 days with PM10 >50 µg/m3.



5.6.2.4 Assessment of Significance 5.6.2.5 The IAQM guidance (Institute of Air Quality Management, 2009) is that the

assessment of significance should be based on professional judgement, with the overall air quality impact of the scheme described as either, insignificant, minor, moderate or major. In drawing these conclusions, the factors set out in Table B.3 should be taken into account. A summary of the professional experience of staff contributing to this assessment is provided in Appendix C.

Table B.3: Factors Taken into Account in Determining Air Quality Significance

Factors

Number of people affected by increases and/or decreases in concentrations and a


The magnitude of the changes and the descriptions of the impacts at the receptors

using the criteria set out in Table B.1 and Table B.2.

Whether or not an exceedence of an objective is predicted to arise in the study area

where none existed before or an exceedence area is substantially increased.

Whether or not the study area exceeds an objective and this exceedence is removed or

the exceedence area is reduced.

Uncertainty, including the extent to which worst-case assumptions have been made.

The extent to which an objective is exceeded, e.g. an annual mean NO2 of 41 g/m3

should attract less significance than an annual mean of 51 g/m3.



5.6.3 APPENDIX C - Professional Experience

5.6.3.1 Prof. Duncan Laxen, BSc (Hons) MSc PhD MIEnvSc FIAQM

Prof Laxen is the Managing Director of Air Quality Consultants, a company which he

founded in 1993. He has over forty years’ experience in environmental sciences and

has been a member of Defra’s Air Quality Expert Group and the Department of

Health’s Committee on the Medical Effects of Air Pollution. He has been involved in

major studies of air quality, including nitrogen dioxide, lead, dust, acid rain, PM10, PM2.5

and ozone and was responsible for setting up the UK’s urban air quality monitoring

network. Prof Laxen has been responsible for appraisals of all local authorities’ air

quality Review & Assessment reports and for providing guidance and support to local

authorities carrying out their local air quality management duties. He has carried out

air quality assessments for power stations; road schemes; ports; airports; railways;

mineral and landfill sites; and residential/commercial developments. He has also been

involved in numerous investigations into industrial emissions; ambient air quality;

indoor air quality; nuisance dust and transport emissions. Prof Laxen has prepared

specialist reviews on air quality topics and contributed to the development of air quality

management in the UK. He has been an expert witness at numerous Public Inquiries,

published over 70 scientific papers and given numerous presentations at conferences.

He is a Fellow of the Institute of Air Quality Management.

5.6.3.2 Laurence Caird, MEarthSci CSci MIEnvSc MIAQM

Mr Caird is a Principal Consultant with AQC, with eight years’ experience in the field of

air quality including the detailed assessment of emissions from road traffic, airports,

heating and energy plant, and a wide range of industrial sources including the thermal

treatment of waste. He has experience in ambient air quality monitoring for numerous

pollutants using a wide range of techniques and is also competent in the monitoring

and assessment of nuisance odours and dust. Mr Caird has worked with a variety of

clients to provide expert air quality services and advice, including local authorities,

planners, developers and process operators. He is a Member of the Institute of Air

Quality Management and is a Chartered Scientist.

5.6.3.3 Paul Outen, BSc (Hons)

Mr Outen is a Consultant with AQC, having joined in 2014. He holds a degree in

Environmental Geoscience, having specialised in the study of landfill-related particulate

matter for his final year thesis. Prior to joining AQC he worked as an Air Quality

Consultant at Odournet UK Ltd for 6 years, undertaking a range of air quality and odour

assessments across a number of different industries, as well as managing the

sampling/technical department for the company. He now undertakes air quality

assessments at AQC, utilising the ADMS dispersion models to assess the impacts of a

variety of sources on concentrations of nitrogen dioxide, PM10 and PM2.5.

Full CVs are available at www.aqconsultants.co.uk.

http://www.aqconsultants.co.uk/



5.6.4 APPENDIC D - Modelling Methodology


5.6.4.2 The background concentrations across the study area have been defined using the

national pollution maps published by Defra (2014a). These cover the whole country on

a 1x1 km grid and are published for each year from 2010 until 2025. The maps include

the influence of emissions from a range of different sources; one of which is road

traffic. As noted in Paragraph 5.3.3.19, there are some concerns that Defra may have

over-predicted the rate at which road traffic emissions of nitrogen oxides will fall in the

future. The maps currently in use were verified against measurements made during

2010 at a large number of automatic monitoring stations and so there can be

reasonable confidence that the maps are representative of conditions during 2010.

Similarly, there is reasonable confidence that the reductions which Defra predicts from

other sectors (e.g. rail) will be achieved.

5.6.4.3 In order to calculate background nitrogen dioxide and nitrogen oxides concentrations in

2013, it is assumed that there was no reduction in the road traffic component of

backgrounds between 20106 and 2013. This has been done using the source-specific

background nitrogen oxides maps provided by Defra (2014a). For each grid square,

the road traffic component has been held constant at 2010 levels, while 2013 values

have been taken for the other components. Nitrogen dioxide concentrations have then

been calculated using the background nitrogen dioxide calculator which Defra (2014a)

publishes to accompany the maps. The result is a set of ‘adjusted 2013 background’

concentrations.

5.6.4.4 Two separate sets of 2018 background nitrogen dioxide and nitrogen oxides

concentrations have been used for the future-year assessment. The 2018 background

‘without emissions reduction’ has been calculated using the same approach as

described for the 2013 data: the road traffic component of background nitrogen oxides

has been held constant at 2010 values, while 2018 data are taken for the other

components. Nitrogen dioxide has then been calculated using Defra’s background

nitrogen dioxide calculator. The 2018 background ‘with emissions reduction’ assumes

that Defra’s predicted reductions occur from 2013 onward. This dataset has been

derived first by calculating the ratio of the unadjusted mapped value for 2018 to the

unadjusted mapped value for 2013. This ratio has then been applied to the ‘adjusted

2013 background’ value (as derived in Paragraph 5.6.4.3).

5.6.4.5 For PM10 and PM2.5, there is no strong evidence that Defra’s predictions are unrealistic

and so the year-specific mapped concentrations have been used in this assessment.

5.6.4.6 Model Inputs

6 This approach assumes that has been no reduction in emissions per vehicle but also that traffic volumes have

remained constant. This is not the same as the assumption made for dispersion modelling, in which emissions per vehicle are held constant while traffic volumes are assumed to change year on year. Overall, this discrepancy is unlikely to influence the overall conclusions of the assessment.



5.6.4.7 Roads

5.6.4.8 Predictions have been carried out using the ADMS-Roads dispersion model (v3.2).

The model requires the user to provide various input data, including emissions from

each section of road, and the road characteristics (including road width and street

canyon height, where applicable). Vehicle emissions have been calculated based on

vehicle flow, composition and speed data using the Emission Factor Toolkit (Version

6.0.1) published by Defra (2014a). For nitrogen dioxide, future-year concentrations

have been predicted once using year-specific emission factors from the EFT, and once

using emission factors for 20137, which is the year for which the model has been

verified.

5.6.4.9 The model has been run using the full year of meteorological data that corresponds to

the most recent set of nitrogen dioxide monitoring data (2013). The meteorological data

has been taken from the monitoring station located at Heathrow Airport, which is

considered suitable for this area.

5.6.4.10 Traffic data for the assessment study area have been taken from the London

Atmospheric Emissions Inventory (LAEI) (GLA, 2013). Traffic speeds have been

based on those presented in the LAEI, with some having been adjusted based on

professional judgement, taking account of the road layout, speed limits and the

proximity to a junction. The traffic data used in this assessment are summarised in

Table D.1.

5.6.4.11 The route of development traffic to and from the sites is not known, and therefore the

development traffic has been distributed across the road network by assuming 50:50

splits at each major road junction – i.e. for Site 18, 50% use Salusbury Road and 50%

uses Kilburn High Road and then where Kilburn High Road meets Chamberlayne

Road, 50% moves north and 50% moves south.

5.6.4.12 In terms of the Canterbury Works, it is advised that the development traffic may access

the site from Albert Road, and exit the site onto Canterbury Road. As this is not

definitely determined, the worst-case assumption has been made that all development

traffic will access and exit the site from Canterbury Road.

7 i.e. combining current-year emission factors with future-year traffic data.



Table D.1: Summary of Traffic Data used in the Assessment (AADT) a

Road Link 2013 2018 (Without

Scheme)

2018 (With

Site 18)

2018 (With

Canterbury

Works)

AADT %HD

V

AADT %HD

V

AADT %HD

V

AADT %HD

V

Salusbury Road

(North of

Brondesbury

Road)

14,60

4

5.1 14,86

6

5.1 14,89

1

5.2 14,89

1

5.2

Salusbury Road

(South of

Brondesbury

Road)

30,55

7

4.6 31,10

6

4.6 31,13

1

4.6 31,13

1

4.6

Salusbury

(Premier Corner

RB entrance)

15,27

9

4.6 15,55

3

4.6 15,56

5

4.6 15,56

5

4.6

Salusbury

(Premier Corner

RB)

5,070 16.0 5,162 16.0 5,187 16.1 5,187 16.1

Salusbury

(Premier Corner

RB exit)

8,089 5.6 8,235 5.6 8,235 5.6 8,235 5.6

Harvist Road 9,938 5.4 10,11

7

5.4 10,11

7

5.4 10,11

7

5.4

Brondesbury Road 14,81

1

6.7 15,07

6

6.7 15,07

6

6.7 15,07

6

6.7

Premier Corner

(North)

15,27

9

4.6 15,55

3

4.6 15,56

5

4.6 15,56

5

4.6

Premier Corner

(South)

5,070 16.0 5,162 16.0 5,174 16.0 5,174 16.0

Kilburn Lane

(Premier Corner

RB east)

8,089 5.6 8,235 5.6 8,235 5.6 8,235 5.6

Kilburn Lane

(Premier Corner

RB)

5,070 16.0 5,162 16.0 5,187 16.1 5,187 16.1



Kilburn Lane (west

of RB)

10,14

1

16.0 10,32

3

16.0 10,34

8

16.0 10,34

8

16.0

Fernhead Road 18,56

9

5.1 18,90

2

5.1 18,90

2

5.1 18,90

2

5.1

Banister Road 10,14

1

16.0 10,32

3

16.0 10,34

8

16.0 10,34

8

16.0

Chamberlayne

(North of Kilburn

Lane)

12,65

4

11.3 12,88

2

11.3 12,89

4

11.3 12,89

4

11.3

Chamberlayne

(South of Kilburn

Lane)

12,10

6

7.6 12,32

3

7.6 12,33

6

7.7 12,33

6

7.7

Carlton Vale 16,17

9

5.6 16,47

0

5.6 16,47

0

5.6 16,47

0

5.6

Albert Road b 0 0.0 0 0.0 0 0.0 50 30.0

Canterbury Roadb 0 0.0 0 0.0 0 0.0 50 30.0

a This is just a summary of the data entered into the model, which have been input as

hourly average flows of motorcycles, cars, buses, Light Goods Vehicles and Heavy

Goods Vehicles, as well as diurnal flow profiles for these vehicles.

b There is no baseline traffic data for Albert Road or Canterbury Road and therefore

only development traffic is presented.



5.6.4.13 Diurnal flow profiles for the traffic have been derived from the national diurnal profiles

published by DfT (DfT, 2011). Figure D.1 shows the road network included within the

model and defines the study area.

Figure D.1:Modelled Road Network




5.6.4.14 Model Verification

In order to ensure that ADMS-Roads accurately predicts local concentrations, it is

necessary to verify the model against local measurements. The verification

methodology is described below.


5.6.4.16 Background concentrations of nitrogen dioxide have been taken from the national

maps of background concentrations available from the Defra LAQM Support website

(Defra, 2014a). The background concentrations for each of the diffusion tube locations

are presented in Table D.2.

Table D.2: Background Concentrations used in the Verification for 2013

Diffusion Tube Grid square NOx NO2

BRT48 - Kilburn Park Road 525202,182526 66.5 36.8

BRT56 – Chamberlayne

Road

523635,183153 59.7 33.1

5.6.4.17 Traffic Data

5.6.4.18 Traffic data for the roads adjacent to the verification sites have been taken from the

London Atmospheric Emissions Inventory (LAEI) (GLA, 2013). A summary of the

traffic data used in the model verification are presented in Table D.3.

Table D.3: AADT Traffic Data used in the Model Verification

Road Link AADT %HDV

Chamberlayne Road 10,157 12.5

Kilburn Park Road 5,391 27.1

Shirland Road East of

Kilburn Park Road

3,253 19.0

Shirland Road West of

Kilburn Park Road

6,684 18.9

Shirland Road West of

Walterton Road

8,913 7.8

5.6.4.19 Nitrogen Dioxide

5.6.4.20 Most nitrogen dioxide (NO2) is produced in the atmosphere by reaction of nitric oxide

(NO) with ozone. It is therefore most appropriate to verify the model in terms of

primary pollutant emissions of nitrogen oxides (NOx = NO + NO2). The model has

been run to predict the annual mean NOx concentrations during 2013 at the Kilburn



Park Road and Chamberlayne Road diffusion tube monitoring sites. Concentrations

have been modelled at 2.5 m, the height of the monitors.

5.6.4.21 The model output of road-NOx (i.e. the component of total NOx coming from road

traffic) has been compared with the ‘measured’ road-NOx. Measured road-NOx has

been calculated from the measured NO2 concentrations and the predicted background

NO2 concentration using the NOx from NO2 calculator available on the Defra LAQM

Support website (Defra, 2014a).

5.6.4.22 A primary adjustment factor has been determined as the slope of the best-fit line

between the ‘measured’ road contribution and the model derived road contribution,

forced through zero (Figure D.2). This factor has then been applied to the modelled

road-NOx concentration for each receptor to provide adjusted modelled road-NOx

concentrations. The total nitrogen dioxide concentrations have then been determined

by combining the adjusted modelled road-NOx concentrations with the predicted

background NO2 concentration within the NOx from NO2 calculator. A secondary

adjustment factor has finally been calculated as the slope of the best-fit line applied to

the adjusted data and forced through zero (Figure D.3).

5.6.4.23 The following primary and secondary adjustment factors have been applied to all

modelled nitrogen dioxide data:

Primary adjustment factor : 4.691

Secondary adjustment factor: 1.001

5.6.4.24 The results imply that the model has under predicted the road-NOx contribution. This

is a common experience with this and most other models. The final NO2 adjustment is

minor.

5.6.4.25 Figure D.4 compares final adjusted modelled total NO2 at each of the monitoring sites,

to measured total NO2, and shows a 1:1 relationship.



Figure D.1: Comparison of Measured Road NOx to Unadjusted Modelled Road NOx

Concentrations. The dashed lines show ± 25%.

Figure D.2: Comparison of Measured Total NO2 to Primary Adjusted Modelled Total NO2


y = 4.6908x

0

10

20

30

40

50

60

70

80

90

100

110

120

0 10 20 30 40 50 60 70 80 90 100 110 120

Measu

red

Ro

ad

-NO

x (

µg

/m3)

Unadjusted Modelled Road-NOx (µg/m3)

1:1 Line

y = 1.0013x

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80

Measu

red

NO

2 (

µg

/m3)

Adjusted Modelled NO2 (µg/m3)

1:1 Line 1:1 Line



Figure D.3: Comparison of Measured Total NO2 to Final Adjusted Modelled Total NO2


5.6.4.26 PM10 and PM2.5

5.6.4.27 There are no nearby PM10 or PM2.5 monitors. It has therefore not been possible to

verify the model for PM10 or PM2.5. The model outputs of road-PM10 and road-PM2.5

have therefore been adjusted by applying the primary adjustment factor calculated for

road NOx.

5.6.4.28 Model Post-processing

5.6.4.29 Nitrogen oxides and nitrogen dioxide

5.6.4.30 The model predicts road-NOx concentrations at each receptor location. These

concentrations have then been adjusted using the primary adjustment factor, which,

along with the background NO2, is processed through the NOx from NO2 calculator

available on the Defra LAQM Support website (Defra, 2014a). The traffic mix within

the calculator has been set to “All London traffic”, which is considered suitable for the

study area. The calculator predicts the component of NO2 based on the adjusted road-

NOx and the background NO2. This is then adjusted by the secondary adjustment

factor to provide the final predicted concentrations.

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70 80

Measu

red

NO

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µg

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Adjusted Modelled NO2 (µg/m3)

1:1 Line 1:1 Line



5.6.4.31 PM10 and PM2.5

5.6.4.32 The number of exceedences of 50 μg/m3 as a 24-hour mean PM10 concentration has

been calculated from the adjusted-modelled total annual mean concentration following

the relationship advised by (Defra, 2009):

A = -18.5 + 0.00145 B3 + 206/B

where A is the number of exceedences of 50 μg/m3 as a 24-hour mean PM10

concentration and B is the annual mean PM10 concentration. The relationship is only

applied to annual mean concentrations greater than 16.5 μg/m3. Below this

concentration, the number of 24-hour exceedences is assumed to be zero.



5.6.5 APPENDIX E – Construction Mitigation

5.6.5.1 The following is a set of measures that should be incorporated into the

specification for the works. All measures are highly recommended for Site 18.

Those measures is normal type font are highly recommended for Canterbury

Works, and those measures highlighted in italics are only desirable measures for

Canterbury Works, reflecting the lower sensitivity of the site:

5.6.5.2 Communications

develop and implement a stakeholder communications plan that includes

community engagement before and during work on site;

display the name and contact details of person(s) accountable for air

quality and dust issues on the site boundary. This may be the

environmental manager/engineer or the site manager; and

display the head or regional office contact information.

5.6.5.3 Dust Management Plan

Develop and implement a Dust Management Plan (DMP) approved by the

Local Authority which documents the mitigation measures to be applied,

and the procedures for their implementation and management.

5.6.5.4 Site Management

Record all dust and air quality complaints, identify cause(s), take

appropriate measures to reduce emissions in a timely manner, and record

the measures taken;

make the complaints log available to the local authority when asked;

record any exceptional incidents that cause dust and/or air emissions,

either on- or off- site, and the action taken to resolve the situation in the log

book; and

hold regular liaison meetings with other high risk construction sites within

500 m of the site boundary, to ensure plans are co-ordinated and dust and

particulate matter emissions are minimised. It is important to understand

the interactions of the off-site transport/deliveries which might be using the

same strategic road network routes.

5.6.5.5 Monitoring

Undertake daily on-site and off-site inspections where receptors (including

roads) are nearby, to monitor dust, record inspection results, and make the

log available to the Local Authority when asked. This should include

regular dust soiling checks of surfaces such as street furniture, cars and



window sills within 100 m of the site boundary, with cleaning to be

provided if necessary;

carry out regular site inspections to monitor compliance with the DMP,

record inspection results, and make an inspection log available to the

Local Authority when asked;

increase the frequency of site inspections by the person accountable for

air quality and dust issues on site when activities with a high potential to

produce dust are being carried out and during prolonged dry or windy

conditions; and

agree dust deposition, dust flux, or real-time PM10 continuous monitoring

locations with the Local Authority. Where possible commence baseline

monitoring at least three months before work commences on site or, if it is

a large site, before work on a phase commences. Further guidance is

provided by IAQM on monitoring during demolition, earthworks and

construction (Institute of Air Quality Management, 2012b)

5.6.5.6 Preparing and Maintaining the Site

Plan the site layout so that machinery and dust-causing activities are

located away from receptors, as far as is possible;

erect solid screens or barriers around dusty activities or the site boundary

that are at least as high as any stockpiles on site;

fully enclose site or specific operations where there is a high potential for

dust production and the site is active for an extensive period;

avoid site runoff of water or mud;

keep site fencing, barriers and scaffolding clean using wet methods;

remove materials that have a potential to produce dust from site as soon

as possible, unless being re-used on site. If they are being re-used on-site

cover as described below; and

cover, seed, or fence stockpiles to prevent wind whipping.

5.6.5.7 Operating Vehicle/Machinery and Sustainable Travel

Ensure all on-road vehicles comply with the requirements of the London

Low Emission Zone, and the London Non-road Mobile Machinery

standards, where applicable;

ensure all vehicles switch off their engines when stationary – no idling

vehicles;



avoid the use of diesel- or petrol-powered generators and use mains

electricity or battery-powered equipment where practicable;

impose and signpost a maximum-speed-limit of 15 mph on surfaced and

10 mph on un-surfaced haul roads and work areas (if long haul routes are

required these speeds may be increased with suitable additional control

measures provided, subject to the approval of the nominated undertaker

and with the agreement of the local authority, where appropriate);

produce a Construction Logistics Plan to manage the sustainable delivery

of goods and materials; and

implement a Travel Plan that supports and encourages sustainable staff

travel (public transport, cycling, walking, and car-sharing).

5.6.5.8 Operations

Only use cutting, grinding or sawing equipment fitted or in conjunction with

suitable dust suppression techniques such as water sprays or local

extraction, e.g. suitable local exhaust ventilation systems;

ensure an adequate water supply on the site for effective dust/particulate

matter suppression/mitigation, using non-potable water where possible

and appropriate;

use enclosed chutes, conveyors and covered skips;

minimise drop heights from conveyors, loading shovels, hoppers and other

loading or handling equipment and use fine water sprays on such

equipment wherever appropriate; and

ensure equipment is readily available on site to clean any dry spillages,

and clean up spillages as soon as reasonably practicable after the event

using wet cleaning methods.

5.6.5.9 Waste Management

Avoid bonfires and burning of waste materials.

5.6.5.10 Measures Specific to Demolition

Soft strip inside buildings before demolition (retaining walls and windows in

the rest of the building where possible, to provide a screen against dust);

ensure effective water suppression is used during demolition operations.

Hand held sprays are more effective than hoses attached to equipment as

the water can be directed to where it is needed. In addition high volume



water suppression systems, manually controlled, can produce fine water

droplets that effectively bring the dust particles to the ground;

avoid explosive blasting, using appropriate manual or mechanical

alternatives; and

bag and remove any biological debris or damp down such material before

demolition.

5.6.5.11 Measures Specific to Earthworks

Re-vegetate earthworks and exposed areas/soil stockpiles to stabilise

surfaces as soon as practicable; and

use Hessian, mulches or trackifiers where it is not possible to re-vegetate

or cover with topsoil, as soon as practicable.

5.6.5.12 Measures Specific to Construction

Avoid scabbling (roughening of concrete surfaces), if possible;

ensure sand and other aggregates are stored in bunded areas and are not

allowed to dry out, unless this is required for a particular process, in which

case ensure that appropriate additional control measures are in place; and

ensure bulk cement and other fine powder materials are delivered in

enclosedtankers and stored in silos with suitable emission control systems

to prevent escape of material and overfilling during delivery.

5.6.5.13 Measures Specific to Trackout

Use water-assisted dust sweeper(s) on the access and local roads, to

remove, as necessary, any material tracked out of the site. This may

require the sweeper being continuously in use;

avoid dry sweeping of large areas;

ensure vehicles entering and leaving sites are covered to prevent escape

of materials during transport;

inspect on-site haul routes for integrity and instigate necessary repairs to

the surface as soon as reasonably practicable;

install hard surfaced haul routes/areas of hard standing, which are

regularly damped down with fixed or mobile sprinkler systems or mobile

water bowsers, and regularly cleaned;



implement a wheel washing system (with rumble grids to dislodge

accumulated dust and mud prior to leaving the site where reasonably

practicable);

ensure there is an adequate area of hard surfaced road between the wheel

wash facility and the site exit, wherever site size and layout permits; and

access gates should be located at least 10 m from receptors, where

possible.

HS2 Technical Study R12922T101A 4.6 APPENDICES 4.6.1 ... · 4.6.1 Apppendix A - Methodology for...

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