LOCAL AIR QUALITY MANAGEMENT - Wiltshire · 2012-08-03 · LOCAL AIR QUALITY MANAGEMENT SECOND...

LOCAL AIR QUALITY MANAGEMENT

SECOND STAGE - REVIEW AND ASSESSMENT

OF AIR QUALITY IN WEST WILTSHIRE

UNDER PART IV OF THE ENVIRONMENT ACT 1995

MARCH 2000

Contact:-

Kate Bishop

Environmental Protection

West Wiltshire District Council

Bradley Road

TROWBRIDGE

Wilts BA14 ORD

Final Version

Second Stage Review and Assessment of Air Quality in West Wiltshire

ENVR44.TEC 2

C O N T E N T S

1.0 Introduction

1.1 Recommendations from the Stage

1 Review & Assessment Report.

1.2 Proposed changes to the Air Quality

Regulations and the interpretation

made in this report.

2.0 The Second Stage Review & Assessment

process.

2.1 Relevant locations and exposure.

2.2 Screening methods used in this

assessment.

2.2.1 Screening models

2.2.1.1 DMRB

2.2.1.2 AEOLIUS

2.2.1.3 GN24

2.2.2 Monitoring

2.2.2.1 Real Time Analysers

2.2.2.1.1 Measurement for PM10

2.2.2.1.2 Measurement of Sulphur

Dioxide (SO2)

2.2.2.1.3 Measurement of Oxides

of Nitrogen (NOx)

2.2.2.2 Passive Diffusion Tubes

2.2.2.2.1 Nitrogen Dioxide

2.2.2.2.2 1,3-Butadiene

2.3 More about Real Time Analysers

2.3.1 Data Collection

2.3.2 Calibration gas certification

Page No

9

9

10

12

12

12

12

12

13

13

14

14

14

15

15

15

15

16

18

18

18


ENVR44.TEC 3

2.4 Quality Assurance/Quality Control

(QA/QC)

2.4.1 Daily Automatic Calibrations

2.4.2 Instrument Calibration Checks

2.4.3 Six Monthly Calibration

2.4.4 BAM 1020

2.4.5 Data Scaling

2.4.6 Quality Assurance/Quality

Control of NO2 passive

diffusion tubes

3.0 Second Stage Review & Assessment of

Carbon Monoxide

3.1 Introduction

3.2 Second Stage Review & Assessment

3.3 Conclusion


4.1 Introduction


4.2.1 Industrial Emissions

4.2.2 Method of Assessment

4.2.3 Passive Diffusion Tube Survey

4.2.3.1 Problems with the

methodology

4.3 Survey Results

4.4 Conclusion


of Nitrogen Dioxide

5.1 Introduction

5.1.1 Traffic Emissions

Page No

18

18

19

19

19

20

20

21

21

21

21

22

22

22

22

22

23

23

23

24

25

25

25


ENVR44.TEC 4





5.2.3 Method of Assessment with regard

to Traffic

5.2.4 Method of Assessment of Industrial

Sources

5.3 Results of Modelling of Traffic Sources

5.3.1 DMRB

5.3.2 AEOLIUS

5.3.3 Discussion

5.3.4 Conclusion

5.4 Results of Nitrogen Dioxide Diffusion

Tubes from Traffic Sources

5.4.1 Westbury

5.4.2 County Way, Trowbridge

5.4.3 Bradford on Avon

5.4.4 High Street, Semington

5.4.5 Conclusion

5.5 Results of Real Time Monitoring for NOx

Warminster Road, Westbury

5.5.1 Conclusion

5.6 Results of Modelling of Industrial Sources

5.6.1 Conclusion

5.7 Overall Conclusion

6.0 Second Stage Review & Assessment of Sulphur

Dioxide

Page No

26

26

26

26

26

27

27

27

28

29

30

30

30

30

31

31

32

32

35

35

35

36

37


ENVR44.TEC 5

6.1 Introduction


6.3 Monitoring Data

6.4 Conclusion

7.0 Second Stage Review & Assessment of PM10

7.1 Introduction

7.1.1 Important Sources of PM10 on a

National Level




7.3 Results with regard to Industrial Emissions

7.3.1 Blue Circle Cement, Westbury

7.3.2 Cooper Avon Tyres, Melksham

7.3.3 Avon Rubber plc

7.3.4 Wessex Incineration, West

Woodlands, Nr Frome

7.3.5 Ten Mineral Processes in Mendip

District Council's Area


7.4.1 DMRB

7.4.2 AEOLIUS

7.4.3 Discussion

7.4.4 Conclusion

7.5 Results of Automatic Monitoring for PM10


7.5.1 Conclusion

Page No

37

37

38

38

39

39

39

42

42

42

42

42

42

43

43

43

44

44

45

46

46

46

48


ENVR44.TEC 6


ENVR44.TEC 7


8.0 Second Stage Review & Assessment of Lead

8.1 Introduction


8.3 Conclusion

9.0 Summary of Assessments

9.1 Recommendations for Third Stage Review

& Assessment

Glossary of Terms and Abbreviations

References

Tables

Table 1 - Air Quality Objectives

Table 2 - Public Exposure

Table 3 - Results of DMRB Model

Table 4 - AEOLIUS input data

Table 5 - Results of AEOLIUS model for

NO2

Table 6 - Nitrogen Dioxide Diffusion

Tube Survey Results 1999

( g/m3)

Table 7 - Summary of NO2 Monthly Mean

Measured at each Location

( g/m3)

Table 8 - Approximate contributions to

PM10 Concentrations 1998

Table 9 - Results of DMRB Model

Table 10 - Results of AEOLIUS Model

for PM10

Table 11 - Summary of PM10 Monitoring

Data

Figures

Figure 1: NO2 Diffusion Tube

Page No

48

49

49

49

49

50

50

51

54

11

17

27

28

29

33

34

41

44

45

47

16


ENVR44.TEC 8

Appendices

1 - Calculations used for DMRB Model

2 - Calculations used for AEOLIUS Model

3 - Monitoring Equipment Calibration Checklist

4 - Monitoring Equipment Pre-Calibration Checklist

5 - WASP Result for Bristol City Scientific Services

6 - Location Plan of 1,3-Butadiene Survey Sites

7 - Graphs of 1,3-Butadiene Survey Results

8 - Location Plan of NO2 Diffusion Tube Survey,

Westbury

9 - Graph of NO2 Diffusion Tube Survey Results


County Way, Trowbridge


Bradford on Avon


Semington

13 - Graphs of NO2 Real Time Monitoring Data,

Westbury and Bristol Centre

14 - Graphs of PM10 Real Time Monitoring Data at

Westbury

15 - Calculation in Determining Primary Contribution

of PM10

Page No

56

58

63

69

71

73

75

78

80

82

84

86

88

97

110


ENVR44.TEC 9

EXECUTIVE SUMMARY

This report is the Second Stage Review and Assessment of Air Quality in West Wiltshire. It is produced as part

of West Wiltshire District Council's obligations under Part IV of the Environment Act 1995.

This report follows on from the First Stage Review & Assessment Report published in December 1998 which

highlighted that emissions of carbon monoxide, 1,3-Butadiene, Nitrogen Dioxide, Lead, Sulphur Dioxide and

PM10 from various potential sources, including road and industry, could be significant at relevant locations

within the district.

The Second Stage Review & Assessment report provides the technical input to the Second Stage Review &

Assessment process which was carried out throughout 1999. Modelling and monitoring for the pollutants of

concern has been carried out in an attempt to provide predictive concentrations of the pollutants by their

relevant objective compliance date. This report also makes reference to the proposed new air quality objectives

which are due to come into force as the Air Quality (England) Regulations 2000 in early 2000.

The results and findings of this report have highlighted that no further action is required for carbon monoxide or

lead. It is concluded that West Wiltshire District Council will proceed to a Stage 3 Review & Assessment for

1,3-Butadiene, Nitrogen Dioxide, Sulphur Dioxide and PM10. Sources of these emissions are likely to be from

road or industrial sources. The approach for the Third Stage Review & Assessment shall consist of monitoring

and “real time” modelling of the pollutants of concern.


ENVR44.TEC 10

1.0 Introduction

This is a Stage 2 Review & Assessment Report for West Wiltshire District Council in compliance with

the Environment Act 1995. It consists of technical information in relation to further modelling and

monitoring assessments following the conclusions of the Stage 1 Review & Assessment report

published in December 1998.

The Stage 1 Review & Assessment Report was the result of an initial screening process to identify

which of the relevant specified National Air Quality Strategy pollutants (laid down in the Air Quality

Regulations 1997) would be likely to be exceeded by December 2005 and at which locations these

would occur. These locations and pollutants are the focus of this Stage 2 report.

The main purpose of the Review & Assessment process is to enable local authorities to assess current

and future air quality within their administrative districts in a specific „step by step‟ 3 staged approach.

The objectives specified in the Air Quality Regulations 1997 are the standards to which comparisons

must be made. All local authorities were required to carry out the First Stage Review & Assessment

and then proceed to the further stages if necessary. If the results of the third stage Review &

Assessment reveals that the air quality objectives are unlikely to be met by the specified year (presently

2005) then the Authority is required to declare an Air Quality Management Area (AQMA) and provide

an action plan to ultimately control the air quality within that area.

1.1 Recommendations from the Stage 1 Review & Assessment Report

The Stage 1 Review & Assessment Report indicated the possibility of exceedence of the air

quality objectives at December 2005 for the following pollutants:-

Carbon Monoxide

Lead

Nitrogen Dioxide

PM10

Sulphur Dioxide

1,3-Butadiene

This report provides information on the results of the Stage 2 Screening Review & Assessment

of the above pollutants.


ENVR44.TEC 11

1.2 Proposed Changes to the Air Quality Regulations and the Interpretation

made in this Report

In October 1999 a consultation document was published by the Department of Environment,

Transport & the Regions (DETR). This document requested comments on proposed changes to

the Air Quality Regulations, to be cited as the Air Quality (England) Regulations 2000. These

Regulations take into account the objectives of the Air Quality Strategy for England. It is

anticipated that these Regulations will be implemented in early 2000.

These Regulations have changed both the unit of measurement for each specific pollutant (eg

from ppb to g/m3), the pollutant concentration objective and measuring period and the

timescale for the objective to be achieved. A table showing the new objectives in comparison

with the old is shown in Table 1.

For the purpose of this report the main focus is switched to the proposed new objectives.


ENVR44.TEC 12

TABLE 1

Air Quality Objectives

Pollutant Objective Concentration Measured as Due to be achieved by

Benzene 16.2 g/m3 (5ppb)

5ppb

Running annual mean

Running annual mean

31 December 2003

31 December 2005

1,3-Butadiene

2.25 g/m3 (1pph)

1ppb

Running annual mean

Running annual mean

31 December 2003

31 December 2005

Carbon Monoxide

11.6mg/m3 (10ppm)

10ppm

Running 8 hour mean

Running 8 hour mean

31 December 2003

31 December 2005

Lead

0.5 g/m3

0.25 g/m3

0.5 g/m3

Annual mean

Annual mean

Annual mean

31 December 2004

31 December 2008

31 December 2005

Nitrogen Dioxide

200 g/m3 (105ppb)

not to be exceeded more

than 18 times a year.

40 g/m3

150ppb

21ppb

24 hour mean

Annual mean

Hourly mean

Annual mean

31 December 2005

31 December 2005

31 December 2005

31 December 2005

PM10

50 g/m3



40 g/m3

50 g/m3



24 hour mean

Annual mean

24 hour mean

31 December 2004

31 December 2004

31 December 2005

Sulphur Dioxide

350 g/m3 (132 ppb) not

to be exceeded more than

24 times a year.

125 g/m3 (47 ppb) not to

be exceeded more than 3

times a year.

266 g/m3 (100 ppb) not

to be exceeded more than

35 times a year.

1 hour mean

1 hour mean

15 minute mean

31 December 2004

31 December 2004

31 December 2005

Items in italics represent the objectives stated in the Air Quality Regulations 1997


ENVR44.TEC 13

2.0 The Second Stage Review & Assessment Process

The Second Stage Review & Assessment has taken the form prescribed in the DETR Review &

Assessment Pollutant - Specific Guidance (LAQM.TG4(98). Regard is also had to the Draft Review &

Assessment Pollutant Specific Guidance (LAQM.TG4(00)) which is expected to be issued in early 2000

after the consultation period which closed on 4 February 2000.

It should be noted that the aim of the Second Stage Review & Assessment is to provide additional

screening of pollutant concentrations in the Authority's area using simple screening models and

monitoring techniques. It is not intended to provide an accurate prediction of current and future

air quality concentrations across the whole district. LAQM.TG4 also states that the Second Stage

requires local authorities to “focus upon those locations where the maximum impact is expected to

occur, bearing in mind the potential for public exposure”.

If the Second Stage indicates that there is a risk that an air quality objective may not be met by the

relevant future year, then the Authority will need to undertake a detailed and accurate appraisal as part

of a third stage Review & Assessment.

2.1 Relevant Locations and Exposure

All work in relation to the assessment of air quality must be focussed on those locations where

members of the public are likely to be exposed over the averaging period of the pollutant

objective. This should include locations where likely future developments may affect exposure

to existing sources of air pollution or may result in new sources. Table 2 outlines the procedure

to be followed.

2.2 Screening Methods used in this Assessment

2.2.1 Models

Due to the potential emissions of pollutants coming from both point and road sources as

highlighted in the First Stage Review & Assessment Report, three models have been used

in the Second Stage Review & Assessment:-

- Design Manual for Roads and Bridges (DMRB).

- Assessing the Environment of Locations in Urban Streets (AEOLIUS).

- Environment Agency - Quality Impact of Stationary Sources (EN24).

A brief outline of these models is given below:-

2.2.1.1 DMRB

DMRB Volume II Section 3 Part 1 Air Quality has been used in this Review &

Assessment to assess the impact of traffic on air quality. DMRB was revised in

1999 and it is this version that has been used.


ENVR44.TEC 14

The methodology consists of a number of tables which allows the user to input

vehicle flows of heavy and light vehicles, vehicle speed and the prediction year to

be modelled. Within the methodology there are a number of look up tables to

correct for vehicle speed, pollutant concentration at a distance from the road,

emission reduction factors and the relationship between annual mean

concentrations of NOx and NO2. After the calculation has been made a prediction

of the pollutant concentration at the nearest receptor is determined and

comparisons can be made with the Air Quality objectives by using correction

factors. For the purposes of this Review & Assessment this information has been

directly inputted into a spreadsheet for ease of calculation. The spreadsheet

calculations are contained within Appendix 1 of this report and Appendices 8, 10,

11 and 12 shows these locations as green highlighted areas.

2.2.1.2 AEOLIUS

This model was developed by the Meteorological Office, Bracknell, Berks. It is a

DOS-based programme which relies upon traffic speed and traffic flow data. Its

primary use is to determine the influence of street canyons on air quality. A street

canyon is a relatively narrow street with buildings on either side which line up

continuously. The model relies on traffic speed, flow data, street width, street

height and wind speed.

The model calculates the pollution concentration in comparison with the Air

Quality objectives.

For the purposes of this assessment, AEOLIUS has been used. This model has

been designed for use specifically as part of a Stage 2 Review & Assessment. It

should be noted that the model allows the user to input their own emission factors

to represent the local vehicle mix. However, no detailed data was available and

so default emission factors have been used. Wind speed is also an important

factor affecting dispersion within canyon streets. No accurate data was available

and a wind speed of two m/s has been applied to give a worst case for dispersion.

The results of this model are contained within Appendix 2 of this report and

Appendix 11 shows these locations as blue highlighted areas.

.

2.2.1.3 GN 24

This is a paper based model produced by the Environment Agency to estimate the

impacts of stationary pollution sources (ie factories) on local air quality. The

document provides pre-calculated charts for estimating local air pollution impacts

from stack emissions. However, it is important to note that there are certain

limitations to using the guidance and it should not be used if any of the following

are applicable:-

If the stack is in an area where there are significant local variations in ground

level (ie, where the ground rises above the stack height within a distance of 10

stack heights).

If the stack height is either below 20 metres or above 200 metres in height.


ENVR44.TEC 15

If the stack is near a building that rises to more than 40% of the stack height

within 5 stack heights.

If the particles released from the plume have diameters of more than 20 gm3.

If the bulk density of the efflux gas is significantly higher or lower than for air

under the same conditions, or the release temperature is significantly below

the ambient temperature.

If the exit velocity is less than 10 m/s or more than 25 m/s.

2.2.2 Monitoring

Two types of monitoring have been used in the Second Stage Review & Assessment

process:-

Real time analysis.

Passive diffusion tubes.

2.2.2.1 Real Time Analysers

Three real time analysers have been bought by this Authority to monitor for

PM10, Sulphur Dioxide and Nitrogen Dioxide. Real time analysers are regarded

as the most accurate of all pollutant monitoring methods but must be

accompanied by a suitable Quality Assurance and Quality Control (QA/QC)

System to take account of analyser drifts and to ensure that the results obtained

can be traced back to a known gas standard. More is discussed on QA/QC later

in this report.

All three analysers are sited in a roadside enclosure at a roadside site in

Warminster Road, Westbury, the site location is shown in pink on the plan in

Appendix 8. The site was chosen because Warminster Road has historically been

regarded as a heavily trafficked road taking a mix of light and heavy duty

vehicles (LDV and HDV). Both commercial and residential properties are

situated along Warminster Road, Westbury. It was felt that this site would be

representative of the relevant locations and averaging periods for the various

pollutants monitored and would take into account any influences on air quality in

the town from specific industrial sites.

2.2.2.1.1 Measurement for PM10

To monitor for PM10 a BAM 1020 analyser is used. This

automatically measures and records dust concentrations with built in

data logging. The sampling head used on this equipment is specific to

only allow particles less than 10 microns in size through to ensure that

PM10 is accurately measured.

The analyser uses the principle of beta absorption to provide sample

determination of mass concentration. An energy source of beta

particles produces repeatable measurement characteristics.

A glass fibre filter tape is used (30mm wide by 20 metres long) and

allows for long periods of monitoring. A known amount of electron

scattering and attenuation through a clean filter is compared with that


ENVR44.TEC 16

of a dust sampled filter. The mass concentration is then calculated by

the ratio of the number of detected beta particles passing through the

filter and the sample volume.

2.2.2.1.2 Measurement of Sulphur Dioxide (SO2)

To monitor for SO2 an APi M100A SO2 analyser is used. This

instrument uses the process of fluorescence of SO2 due to the

absorption of UV energy to determine SO2 concentration in the

sample.

The SO2 contained within the sample absorbs in the 190nm - 230nm

region. The UV lamp within the analyser emits ultra violet radiation

which passes through a 214nm filter. This excites the SO2 molecules

and as a result fluorescence is produced. The amount of fluorescence

is measured by a photo multiplier tube (PMT) which has a secondary

UV filter. The PMT transfers the light energy into an electrical signal

which is directly proportional to the light energy in the sample stream

being analysed. The fluorescent radiation that impinges upon the

PMT is, therefore, directly proportional to the concentration of SO2 in

the sampled air.

2.2.2.1.3 Measurement of Oxides of Nitrogen (NOx)

To monitor for NOx an APi M200 analyser is used. This instrument

measures the concentration of Nitric Oxide (NO) and total oxides of

Nitrogen (NOx) and then by calculation the NO2 concentration is

determined.

The instrument works on the principle of chemiluminescence.

Ambient air is pumped into a measurement cell and the amount of NO

is measured by adding ozone (O3) into the measurement cell. The NO

is converted to NO2 in an excited state which looses energy by

emitting photo light. This is detected and the amount of light emitted

is equivalent to the concentration of NO. Next the instrument

measures the amount of NOx by passing ambient air through a

reduction catalyst converter. This has the effect of reducing the NO2

to NO. The NO is then reacted to NO2 again and recorded. The NO2

concentration in the air sample is calculated by taking the amount of

recorded NO away from the amount of recorded NOx.

2.2.2.2 Passive Diffusion Tubes

Two types of passive diffusion tubes have been used as part of the assessment.

Nitrogen Dioxide

1,3-Butadiene

2.2.2.2.1 Nitrogen Dioxide

West Wiltshire District Council has 14 sites within the district to

monitor for Nitrogen Dioxide using passive diffusion tubes.


ENVR44.TEC 17

A Nitrogen Dioxide passive diffusion tube is a clear plastic tube open

at one end and at the closed end a mesh is impregnated with a

pollutant absorbing chemical. The diffusion tube collects the pollutant

during the exposure period and then is resealed and returned to a

laboratory for analysis. Each tube is exposed for a month period. The

laboratory then assesses the quantity of the pollutant absorbed by

calculating the average ambient NO2 concentration over the exposure

period.

Each tube is mounted on a lamp-post or similar structure ensuring that

the open end is at the bottom to prevent rain water collection.

Figure 1 NO2 Diffusion Tube

Impregnated gauze

Plastic cap

75mm Tube body (about 15mm diameter)

Protective cap

to be removed during sampling

Accuracy +/- 20%

2.2.2.2.2 1,3-Butadiene

Two sites have been set up to measure 1,3-Butadiene by using passive

diffusion tubes. The main difference between these tubes and NO2

diffusion tubes is that they are made of metal. Additionally, the

technique uses a molecular sieve 13 x as a method of ensuring 1,3-

Butadiene is adsorbed on the tube.

After two weeks of exposure the used diffusion tube is returned to the

laboratory for analysis and the concentration of 1,3-Butadiene is

determined.


ENVR44.TEC 18

TABLE 2

Public Exposure

Pollutant Averaging Period

Focus of Review &

Assessment

Example

Sulphur Dioxide

Nitrogen Dioxide

15 minute

short

averaging

1 hour periods

Any non-occupational

near ground level

outdoor location

where members of the

public might

reasonably be

expected to be present

over the relevant

averaging period.

A playing field

downwind of a point

source (factory).

Pavement of a busy

shopping street.

Benzene

1,3-Butadiene

Carbon Monoxide

Lead

Nitrogen Dioxide

PM10

Annual mean

Annual mean

long

8 hour mean averaging

periods

Annual mean

Annual mean

24 hour mean

Non-occupational,

near ground level

outdoor locations, ie:

background locations

roadside locations

where members of the

public might

reasonably be

expected to be

regularly exposed to

outdoor air for a

substantial part of the

day.

In the vicinity of

housing, schools,

hospitals, etc.

Note: Exceedances of the objectives at any location where public exposure over the relevant averaging

period would not be realistic should not be considered.


ENVR44.TEC 19

2.3 More about the Real Time Analysers

2.3.1 Data Collection

Data is collected from the analysers via telemetry. The data is stored on a desk top

computer at the West Wiltshire District Council Offices.

NOx, NO and NO2 data is collected as 1 hour averages

PM10 data is collected as 1 hour averages

SO2 data is collected as 15 minute and 1 hour averages

By collecting data in this manner comparisons can be made with the air quality

objectives.

2.3.2 Calibration gas Certification

Two calibration gases are used, SO2 for the APi M100A and NO for the APi M200A.

These gases are obtained from Messer UK in Reigate. All calibration gases are traceable

to the national standard, where possible. In cases where no national standard exists, the

gas concentration is made up gravimetrically and then analysed by a number of methods

to cross check that the calculated concentration is the same as the measured

concentration.

2.4 Quality Assurance/Quality Control (QA/QC)

To ensure that the information obtained from the analysers is as accurate as possible and to

quantify any instrument drifts a stringent QA/QC protocol is followed.

2.4.1 Daily Automatic Calibrations

Both the APi M100A and APi M200A are subjected to daily automatic calibration. This

provides a daily check on the performance of each instrument. It should be noted that

these results are not used for instrument scaling.

In the APi M100A analyser, zero air is generated by passing ambient air through a

charcoal scrubber, before entering the reaction cell.

The span gas is generated by an SO2 permeation tube which contains a quantity of pure

liquid SO2. The permeation tube is enclosed in an oven which is maintained at a constant

temperature. The zero air is passed across the permeation tube at a constant flow rate.

Provided the flow rate and temperature are kept constant, the amount of SO2 permeating

from the tube into the air stream will be constant.

The gas produced then passes into the reaction cell and a span calibration response is

determined.

In the APi M200A, zero air is generated by passing ambient air through purafil charcoal

scrubbers before it is passed into the reaction cell.

The span calibration response is achieved in a similar way to the APi M100A, except that

the span gas is generated by an NO2 permeation tube containing pure liquid NO2.


ENVR44.TEC 20

2.4.2 Instrument Calibration Checks

These calibration checks are carried out every two weeks on the APi M100A and APi

M200A. This allows instrument drifts to be fully qualified and documented using

traceable calibration gas standards and the results are used to scale data.

A copy of the equipment calibration checklist can be found in Appendix 3 of this report.

The fortnightly calibration procedure requires a zero check on the analyser. This is

achieved by a source of zero air being provided by passing ambient air through the

charcoal scrubber before it enters the reaction cell. Once stability has been achieved (this

is defined as a variation of less than 0.1ppb over a one minute period for the analyser)

three readings are recorded from the instrument display after three ten second intervals.

Next the calibration gas bottle is opened at a pressure of 30 psi. The analyser is allowed

to stabilise for a minimum of ten minutes. Three consecutive readings are taken from the

instrument display, allowing ten seconds between readings. The calibration gas is then

isolated.

By considering the previous calibration results and the results obtained from the

calibration just performed the success of the calibration procedure is determined. The

zero value should not differ by more than 2ppb from the previous calibration. The

span calibration should not differ by more than 5% from that obtained during the

previous calibration.

Additionally, the analyser sample inlet filter is changed when necessary.

At the time of the instrument calibration checks, instrument pre-calibration checks are

made to ensure that the condition of each analyser, before the calibration check, is

assessed and any faults attended to. A copy of the checklist is found in Appendix 4 of

this report.

It should be noted that the BAM 1020 does not require fortnightly calibration, but checks

are carried out every fortnight to ensure the instrument is working correctly.

2.4.3 Six Monthly Calibration

These checks are carried out by our analyser suppliers, Enviro Technology Ltd, at the

same time as servicing of the analysers. They ensure that the measurements from the

analyser are representative and inter-comparable. The calibrations act as an independent

audit of the system performance. Additionally, any site-specific problems that may have

remained undetected will be fully quantified.

2.4.4 BAM 1020

The BAM 1020 PM10 analyser does not require fortnightly calibration checks as

automatically self-calibration of zero and span are applied at the beginning of every cycle

(ie, every 60 minutes). If the instrument fails to perform to its specification, an error is

logged in the memory.

The zero testing of the instrument is based on the unit's ability to hold a constant output

when measuring the blank filter paper. The span measurements are made by

automatically inserting a reference membrane in the measurement path.

The BAM 1020 is serviced once every 6 months and calibrated.


ENVR44.TEC 21

2.4.5 Data Scaling

The data obtained from the APi M100A and APi M200A analysers are scaled to take into

account instrument drift. The data scaled is that which was collected in the two week

period before the calibration check was made.

The corrected data is determined using the following procedure:-

Instrument Zero = Vz

Instrument Span (F) = c/(Vs-Vz)

Pollutant Concentration (ppb) = F(Va-Vz)

Conversion to g/m3 = Pollutant Conc x 1.91

Vz is the response of the analyser when the pollutant being measured is not in the sample

airstream.

Vs is the response of the analyser to an accurately known concentration, c.

Va is the recorded signal from the analyser sampling ambient air.

2.4.6 Quality Assurance/Quality Control of NO2 Passive Diffusion Tubes

The laboratory we use is Bristol City Scientific Services. They follow various QA/QC

controls to ensure that the analysis is as accurate as possible.

Each batch of tubes analysed is accompanied by check standards, regeant blank, tube

blank and a QC solution which is supplied by AEA Technology. The results of the

QC solution checks are sent to AEA Technology on a monthly basis to tie in with the

DETR national NO2 diffusion tube survey.

Additionally, the lab also participates in a scheme run by the Health & Safety

laboratory called the Workplace Analysis Scheme for Proficiency (WASP). Each

month Bristol City Scientific Services Lab is sent a doped diffusion tube which is

analysed and returned to WASP.

A copy of the latest WASP result for Bristol City Scientific Services is attached as

Appendix 5 to this report.

Additionally, our QA/QC checks are to ensure that when a tube batch is received they are

stored air tight in the fridge. On the day of sampling they are removed from the fridge

and installed. Any laboratory blanks sent to us are kept in the fridge and taken out when

the exposed tubes are installed and collected.

When the tubes are collected, they are immediately packaged and sent to the laboratory

for analysis.


ENVR44.TEC 22

3.0 Second Stage Review & Assessment of Carbon Monoxide

The Government has adopted an 8 hour running mean of 11.6mg/m3

(10ppm) as an air quality standard for carbon monoxide (CO), with an

objective for the standard to be achieved as the maximum 8 hour

running mean by the end of 2005. The date for this objective to be

achieved is shortly to be changed to the end of 2003. The focus of the

Authority's Review & Assessment for CO should be at

non-occupational, near ground levels at outdoor locations where

people might reasonably be expected to be exposed over a 8 hour

period.

3.1 Introduction

This Authority will need to carry out a third stage Review & Assessment by CO if the Second

Stage Review & Assessment indicates that there is a significant risk of the objective not being

achieved by end 2005 (and shortly end 2003).

The First Stage Review & Assessment report highlighted that there was potential for a Part A

process located near Frome known as Wessex Incineration, West Woodlands, Frome, to emit

significant quantities of CO. This process is approximately 18km from Trowbridge and about

4km from Horningsham, the nearest village to the site within West Wiltshire.


The Review & Assessment: Pollutant Specific Guidance (LAQM - TG4(00)) states that to assess

for emissions of CO from industrial sources predictive modelling studies should be carried out.

Predictions of CO concentrations should be carried out using the Environment Agency's

“Guidance for Estimating the Air Quality Impact of Stationary Sources (GN24)”.

Unfortunately, it has not been possible to make an assessment of this process using the GN24

methodology because the flues are less than 20 metres in height.

West Wiltshire District Council has spoken to the Environment Agency who authorise this

process and it is believed that significant CO emissions will not arise from this source and affect

residents of West Wiltshire in significant quantities. To back up this statement, the Environment

Agency have compared the Wessex Incineration site to some air dispersion modelling carried

out at a similar cattle cremator at Dimmer near Castle Carey. This confirmed that emissions of

CO would be insignificant in our district.

3.3 Conclusion

The Second Stage Review & Assessment has indicated that the risk of the carbon monoxide air

quality objective being exceeded in 2005 or 2003 in the District Council's area is negligible, in

locations where there might be exposure over the 8 hour period.

Therefore, West Wiltshire District Council will not need to undertake a third stage Review &

Assessment for this pollutant.


ENVR44.TEC 23

4.0 Second Stage Review & Assessment of 1,3- Butadiene

The Government has adopted a maximum running mean of 2.25 g/m3

(1ppb) as an air quality standard for 1,3-Butadiene, with an objective

for the standard to be achieved by end of 2005. The date for this objective

to be achieved is shortly to be changed to the end of 2003. The focus of

the Authority's Review & Assessment for 1,3-Butadiene should be at

non-occupational, near ground level outdoor locations where people might

reasonably be expected to be exposed over an annual period.

4.1 Introduction

This Authority will need to carry out a third stage Review & Assessment of 1,3-Butadiene if the

Second Stage Review & Assessment indicates that there is significant risk of the objective not

being achieved by end 2005 (and shortly by the end 2003).

The First Stage Review & Assessment report highlighted that there was potential for a Part B

authorised process located in Melksham known as Cooper Avon Tyres, Bath Road, Melksham,

to emit significant quantities of 1,3-Butadiene. This is because 1,3-Butadiene is a constituent in

the rubber which is used to make tyres at the site. This process is in the centre of Melksham and

is in very close proximity to a number of large residential areas.



The Review & Assessment: Pollutant Specific Guidance (LAQM TG4 (00)) states that

to assess for emissions of 1,3-Butadiene from industrial sources, predictive modelling

studies should be carried out. Predications of 1,3-Butadiene concentrations should be

carried out using the Environment Agency's “Guidance for Estimating the Air Quality

Impact of Stationary Sources (GN24)”.

The guidance also suggests that passive diffusion tubes can be used to predict

concentrations, but the method of assessment has not been fully validated and any result

must be treated with a degree of caution.

4.2.2 Method of Assessment

Due to the fact that limited information is available on emissions from Cooper Avon

Tyres and because the 1,3-Butadiene may be emitted from fugitive sources, West

Wiltshire District Council has been unable to predict emissions of 1,3-Butadiene using

the Environment Agency GN24 guidance.

The most cost effective method of indicating the presence or absence of 1,3-Butadiene is

to use passive diffusion tubes. It has been recognised that this method of assessment has

not been fully validated and results should be used with caution.


ENVR44.TEC 24

4.2.3 Passive Diffusion Tube Survey

This survey has been carried out at two locations in Melksham. One site is outside The

Unicorn Public House, Bath Road, Melksham, and the other is outside a property in

Scotland Road, Melksham. These locations have been chosen because they are near

areas where non-occupational exposure is likely over the annual exposure period, and

they represent overall upwind and downwind conditions at the factory taking into

account the south westerly prevailing wind. A location plan of the diffusion tube sites in

relation to the factory is enclosed as Appendix 6 of this report. The survey started on

12 July 1999 and ended on 25 January 2000 and the tubes changed every two weeks.

4.2.3.1 Problems with the Methodology

There is no set validated methodology for determining Environmental

Concentrations of 1,3-Butadiene using passive diffusion tubes. Method

MDHS has been used to assess concentrations of 1,3-Butadiene. This is a

method which is approved by the Health & Safety Executive for the

analysis of butadiene in air.

1,3-Butadiene is very volatile and hygroscopic. All steps have been made

to ensure that the risk of water interference is reduced. This has been

ensured by the following:-

Use of diffusion caps with membranes

Minimisation of sampling times

Tubes housed in rain proof boxes

Other materials that can adsorb onto molecular sieve 13 x will be collected.

To effectively separate the 1,3-Butadiene an adequate gas chromatography

methodology is requested by the laboratory.

There is some concern that methodology MDH5 63 cannot detect below

1ppb and, therefore, very low concentrations of 1,3-Butadiene may not be

detected.

4.3 Survey Results

Graphs showing the results of the diffusion tube survey can be found in Appendix 7 of this

report.

The fortnightly results have been averaged and from 12 July 1999 to 25 January 2000 the

average is 6.66 g/m3

at Scotland Road and 5.16 g/m3 Bath Road. Whilst these a six month

averages, the indication is that in either case the concentration is likely to be above the 2.25

g/m3 annual objective.


ENVR44.TEC 25

4.4 Conclusion

The Second Stage Review & Assessment has indicated that the risk of the 1,3-Butadiene air

quality objective being exceeded in 2005 or by 2003 in the District Council's area may be

potentially significant at locations where there might be exposure over the annual period.

It is recognised that as there is no validated diffusion tube monitoring technique that inaccuracies

may have occurred. This means that the results should be viewed with extreme caution.

Further work will be required to gain more accurate and reliable data.


ENVR44.TEC 26

5.0 Second Stage Review & Assessment of Nitrogen Dioxide

The Government has adopted an annual mean of 40 g/m3 (21ppb) and a 1 hour

mean of 286 g/m3 (150ppb) as the air quality standards for Nitrogen Dioxide.

The objectives are that both standards are to be achieved by the end of 2005. It

is likely that the 1 hour standard to be achieved will be changed to 200 g/m3

(105ppb). This standard is not to be exceeded more than 18 times per year by

end 2005.

The focus of the Authority's Review & Assessment for the annual

mean objective for Nitrogen Dioxide should be at non-occupational, near

ground level outdoor locations. These include background and roadside

locations and other locations where potentially significant groups might be

regularly exposed.

For the 1 hour mean objective, the focus should include

any non-occupational, near ground level outdoor locations (including kerbside

sites) given that short time exposures are potentially likely at these locations.

5.1 Introduction

This Authority will need to carry out a third stage Review & Assessment of Nitrogen Dioxide

(NO2) if the Second Stage Review & Assessment indicates that there is significant risk of the

objectives being exceeded by the end of 2005.

The First Stage Review & Assessment report highlighted that there was potential for significant

quantities of NO2 being released via the following sources:-

Traffic emissions

Industrial emissions


NO2 is a significant pollutant from vehicle exhausts. The following roads were,

therefore, highlighted because of the high annual average daily traffic flows (AADT):-

A350 High Street, Semington, - AADT 1996 was 17976. In 1998 the AADT was

increased to 17733 according to the Travel Report Wiltshire 1998.

A363 Bradford on Avon, Town Bridge, AADT 1996 was 17908

AADT had increased to 18600 according to the Travel Report Wiltshire 1998.

County Way, Trowbridge, AADT 1996 was 24965. In 1998, the AADT had

increased to 25506 according to the Travel Report Wiltshire 1998.

Additionally, although not indicated in the First Stage Review & Assessment the A350

Warminster Road, Westbury, was included. Although no automatic counts had been

carried out there, a manual 12 hour count in 1996 revealed a traffic flow of 14832. The


ENVR44.TEC 27

AADT 1996 has been calculated by using a correction factor of 1.22 as suggested by

Wiltshire County Council thus the 1996 AADT Warminster Road was 18012.


Three Part A processes were highlighted in the First Stage Review & Assessment report

as having the potential to release significant quantities of NO2.

Blue Circle Cement, Trowbridge Road, Westbury, (a cement and lime process).

Premiere Environmental Ltd, Chemical Road, West Wilts Trading Estate, Westbury,

(an oil and solvent recovery process).

Wessex incineration, Buns Lane, West Woodlands, Frome (an animal carcass

incinerator).

A further Part A process to carry out an oil and solvent recovery had been notified to this

Authority. This process will be based at Western Solvents Ltd, Brook Lane, Westbury

and was authorised by the Environment Agency in December 1999.



The Review & Assessment: Pollutant Specific Guidance (LAQM TG4(00)) states that to

assess for significant emissions of NO2 from traffic the Design Manual for Roads and

Bridges (DMRB) should be used. This is a screening model and more detailed

information on this is contained in paragraph 2.2.1 of this report.

Nitrogen Dioxide passive diffusion tubes can also be used to determine levels of NO2.

However, the tube locations must be representative of roadside or kerbside locations

relevant to public exposure.


The Review & Assessment: Pollutant Specific Guidance (LAQM TG4 (00)) states that

to assess for emissions of NO2 from industrial sources, predictive modelling studies

should be carried out. Predictions of NO2 concentrations should be determined using the

Environment Agency's “Guidance for Estimating the Air Quality Impact of Stationary

Sources (GN24)”.

5.2.3 Method of Assessment with Regard to Traffic

Both DMRB and AEOLIUS modelling packages have been used to determine the impact

of traffic on the air quality in West Wiltshire. This information has provided us with

predictive estimates on the NO2 concentration for 2005.

Additionally, in Semington, Bradford on Avon, Trowbridge and Westbury, NO2 passive

diffusion tubes have been set up. The sites at Westbury have been established since 1994

and are part of the DETR national NO2 network.

The sites in Bradford on Avon, Trowbridge and Semington were established specifically

for the stage 2 Review & Assessment and have been running since March 1999.


ENVR44.TEC 28

In Warminster Road, Westbury, a real time monitoring site has been established since

January 1999 and monitors for SO2, PM10 and NOx. The NOx results form part of this

report in further quantifying levels of NO2 in Warminster Road, Westbury.

5.2.4 Method of Assessment of Industrial Sources

Information has been sought from the Environment Agency on the NO2 emissions from

all four Part A processes, with a view to carrying out an assessment using the

Environment Agency's GN24 guidance.


5.3.1 DMRB

Estimations of the annual mean Nitrogen Dioxide (NO2) concentrations for the end of

2005 were prepared using the DMRB methodology. A DMRB spreadsheet provided by

Stanger Scientific & Environment was used for the assessment. The results are shown in

Table 3. Appendix 1 provides the results in full.

TABLE 3

Results of DMRB Model

Site Annual Mean NO2 2005

( g/m3)

99.8th

Percentile of Hourly

NO2 Average ( g/m3)

A350 High Street

Semington

41

142

Town Bridge

Bradford on Avon

32

113

A350 Warminster Road

Westbury

38

132

County Way

Trowbridge

48

168


ENVR44.TEC 29

5.3.2 AEOLIUS

The town of Bradford on Avon is made up of very narrow canyon streets. To make a

more accurate assessment of NO2 emissions the AEOLIUS model was used.

In determining predictions of NO2 concentrations using the AEOLIUS model, the

information contained in Table 4 has been used.

Estimations of the annual mean in canyon streets for 2005 were prepared using

AEOLIUS. The results are shown in Table 4. Appendix 2 provides the results in full.

TABLE 4

AEOLIUS Input Data

Site Peak Hour Flow Average Hour Flow

Average Hour Speed

(km/h)

Masons Lane 1998

1170

488

41.76

Market Street 1998

1323

551

15

Silver Street 1998

1016

423

19.8

Masons Lane 2005

Without development

1387

578

41.76

Market Street 2005

Without development

1529

637

15

Silver Street 2005

Without development

1183

493

19.8

Masons Lane 2005

With development

1424

593

41.76

Market Street 2005

With development

1565

652

15

Silver Street 2005

With development

1516

632

198

It should be noted that a proposed major development of a currently redundant factory in the heart of the town

of Bradford on Avon is being considered by this Authority's Development Control Section.

If permission is granted, then traffic flows through the town may be affected. Information supplied by

Wiltshire County Council and obtained from a study of traffic flows both with and without the development

have been obtained. It is these figures that have been used in the AEOLIUS model.

Average hour speeds have been determined by using a moving car observer method.

Average hourly flow data has been estimated by multiplying the peak hour flow information by a factor of 10.

This provides a conservative estimate on which to base our information.


ENVR44.TEC 30

TABLE 5

Results of AEOLIUS Model

Site 1998 Annual Mean NO2

Concentration ( g/m3)

2005 Annual Mean NO2

Concentration ( g/m3)

99.8th

percentile of hourly

NO2 Average

(2005) ( g/m3)

Masons Lane

Bradford on Avon

78.8

Market Street

Bradford on Avon

80.98

Silver Street

Bradford on Avon

79.82

Masons Lane using 2005

predicted traffic levels

without development

71.14

249

Market Street using 2005


without development

73.21

256

Silver Street using 2005


without development

72.26

253

Masons Lane using 2005


with development

71.47

250

Market Street using 2005


with development

73.52

257



with development

75.47

264

5.3.3 Discussion

It should be noted that both DMRB and AEOLIUS models are known to provide

conservative estimates based on worst case scenarios. AADT traffic data has been

derived from the Travel Report Wiltshire 1998. In the case of Warminster Road,

Westbury, no data was contained within the Travel Report Wiltshire1998 and so count

data from 1996 has been used (the only data available for this site).


ENVR44.TEC 31

With regard to Masons Lane, Silver Street and Market Street, Bradford on Avon, no

AADT count data was available in the Travel Report Wiltshire 1998. The data has been

obtained from Wiltshire County Council from a traffic model study carried out in 1998.

For the purposes of all the calculations, a high growth factor has been used in view of the

fact that West Wiltshire is recognised as experiencing high growth.

5.3.4 Conclusion

Predicted concentrations of NO2 using DMRB show that there is potential

exceedance of the annual mean by 2005 at High Street, Semington and County

Way, Trowbridge. All four sites are within the proposed new 1 hour mean

objective of 200 g/m3. With regard to the AEOLIUS modelling in Table 5, all

sites show exceedance of the annual mean and 1 hour mean objective for 2005.

However, both models are known to overestimate. In order to validate the

modelling carried out Nitrogen Dioxide diffusion tubes have been used and the

results are contained in Table 6 and Appendix 9 of this report.

5.4 Results of Nitrogen Dioxide Diffusion Tubes from Traffic Sources

5.4.1 Westbury

Monitoring for NO2 using passive diffusion tubes has been carried out at four locations in

Westbury since 1994. This site forms part of the DETR Nationwide NO2 diffusion tube

survey. The site locations are defined as follows:-

Kerbside site - Warminster Road, Westbury

Intermediate site - Station Road, Westbury

Background site - Oldfield Park, Westbury

Background site - Danvers Way, Westbury

A plan showing the approximate locations of these sites is shown in Appendix 8 of this

report.

The monthly data for 1999 is shown in Table 6. A graph showing the 12 month average

concentrations and predicting the likely 2005 concentration is shown in Appendix 9. It

should be noted that the calculation used to predict the 2005 concentration is specified in

guidance LAQM TG4(00) and is as follows:-

1999 concentration x Correction factor for 2005

Correction factor for 1999

This is as follows:-

1999 concentration x (0.79/0.92)

5.4.2 County Way, Trowbridge

Three sites were chosen around this location following the findings of the First Stage

Review & Assessment Report.


ENVR44.TEC 32

The sites have been running since March 1999. The locations were chosen to get an idea

of the NO2 concentrations in the area and where possible relevant locations have been

chosen.

A plan showing the approximate locations of the sites is shown in Appendix 10 of this

report.

A graph showing the 10 month average concentrations and predicting the likely 2005

concentration is shown in Appendix 9.

It should be noted that the calculation used to predict the 2005 concentration is specified

in guidance LAQM TG4 (00) and is shown in paragraph 5.4.1.

Table 6 shows the monthly data collected for 1999.

5.4.3 Bradford on Avon

Four sites in Bradford on Avon were set up in March 1999 following the publication of

the First Stage Review & Assessment Report.

The site locations are shown in Appendix 11. The locations represent areas where people

are likely to be exposed over the annual period.

Bradford on Avon is an old town made up of narrow canyon streets with high buildings

on both sides of the road. Traffic has increased dramatically over the past 10 years.

There are a number of dwellings in the centre of the town.


concentration is shown in Appendix 9.

In predicting the 2005 concentration, the formula shown in paragraph 5.4.1 has been

used.


5.4.4 High Street, Semington

Three sites along the A350 High Street, Semington, were set up in March 1999 following

the publication of the First Stage Review & Assessment Report.

A plan showing the site location is contained in Appendix 12. The location, as far as

possible, represent areas where people are likely to be exposed over the annual period.


concentrations is shown in Appendix 9.

In predicting the 2005 concentration, the formula shown in paragraph 5.4.1 has been

used.



ENVR44.TEC 33

5.4.5 Conclusion

It is very clear from the graph shown in Appendix 9, that sites at Masons Lane, Bradford

on Avon and County Way, Trowbridge, are likely to exceed the annual NO2 objective in

2005.

A third stage Review & Assessment is to be undertaken to further assess and quantify

NO2 concentrations at these two sites.

5.5 Results of Real Time Monitoring for NOx Warminster Road, Westbury

Since January 1999 we have been monitoring using the APi M200A analyser. Due to the fact

that no QA/QC procedure was in place at that time, results from 1 March 1999 until 31 October

1999 are used in this report. Information about this analyser can be found in paragraph 2.2.2.1.3

of this report.

Monitoring over 8 months has provided us with a fair idea of the air quality at that site.

However, it is important to note that pollutant concentrations vary considerably from hour to

hour and week to week and so the longer a survey has been going, the better the trends can be

analysed.

In this instance we have tried to put the results into a wider perspective by comparing the

concentrations from the Westbury site with concentrations from the national Automatic Urban

Network (AUN) site at Bristol Centre, which is a long term monitoring station. This data has

been obtained via the National Air Quality Archive via the Internet

(http://www.aeat.co.uk/netcen/airqual/welcome.html).

The Bristol Centre site is an urban background station which is located in the centre of the city,

43 metres from a busy road.

The purpose of comparing the results from both sites is to identify how representative the results

we have for Westbury are compared to longer term concentrations. It should be noted that the

1999 data for Bristol Centre has not yet been ratified by the AUN QA/QC network. Therefore,

there may be changes once ratification has taken place.

Comparisons of the data measured in Westbury are made with the same period at Bristol Centre

and also during 1998 at Bristol Centre. Table 7 shows this information and Appendix 13

contains graphs depicting this information.

During October 1999, the results at the Westbury site show some very high NO2 concentrations

which are well above the 1 hour mean objective. At the present time it is unclear why these

concentrations were so high and further work will be carried out into this situation using

meteorological data to justify this result. Additionally, high 1 hour maximum peaks were

experienced in July, September and October, again the reason for these peaks is unclear.


ENVR44.TEC 34

TABLE 6

Nitrogen Dioxide Diffusion Tube Survey Results 1999 ( g/m3)

Site Jan Feb March April May June July Aug Sept Oct Nov Dec Average

Warminster Road,

Westbury

33

44

48

46

43

49

50

41

51

51

59

44

47

Station Road,

Westbury

30

32

32

28

27

31

31

32

26

29

32

24

30

Oldfield Park,

Westbury

20

19

19

15

13

14

17

18

16

20

21

17

17

Danvers Way,

Westbury

18

18

20

14

13

13

14

16

18

22

23

19

17

TLP 79, County Way,

Trowbridge

46

47

39

41

39

43

47

46

52

39

44

TLP56, County Way,

Trowbridge

46

44

40

43

41

44

44

48

42

46

44

TLP70, County Way,

Trowbridge

60

89

58

57

53

54

69

62

55

57

61

13 St Margaret's Street,

Bradford on Avon

49

44

41

45

36

42

49

46

48

44

44

13 Market Street,

Bradford on Avon

44

42

36

37

38

35

35

34

42

35

38

13 Masons Lane,

Bradford on Avon

66

69

60

65

63

51

55

54

39

53

58

13 Silver Street,

Bradford on Avon

38

43

39

37

43

47

46

45

44

42

42

SEMLP1,

Semington

36

46

42

37

40

42

51

42

46

32

41

SEMLP8,

Semington

40

46

40

42

46

50

59

50

34

15

42

SEMLP17,

Semington

Tube

missing

38

40

37

39

45

57

61

22

39

42


ENVR44.TEC 35

TABLE 7

Summary of NO2 monthly mean measured at each location ( g/m3)

Average March April May June July Aug Sept Oct 8

Month

Mean

Standard

Westbury 1999

43

32

32

36

26

27

62

462

90

40 (annual mean)

Bristol 1999

39

35

34

31

32

39

41

142

49

Bristol 1998

39

38

41

29

27

37

46

38

37

1 Hour Maximum March April May June July Aug Sept Oct Standard

Westbury 1999

81

153

108

534

254

108

338

1053

200 g/m3

Bristol 1999

121

115

124

101

122

142

134

111

Bristol 1998

140

122

136

103

78

98

151

132

Graphs showing the results from the Westbury analyser in comparison with Bristol Centre 1999 are in Appendix 13. It should be noted that the peak experienced

on 14 June 1999 at Westbury was due to an air conditioning fault. This was resolved on 15 June 1999.


ENVR44.TEC 36

5.5.1 Conclusion

Both the 1 hour mean objective and annual mean objective currently appear to be being

exceeded at Warminster Road, Westbury, although this could partly be influenced by the

high results obtained in October 1999.

During April to September the NO2 monthly means were similar or lower than those at

Bristol Centre. However, concentrations in Westbury during March, September and

October were higher than those at Bristol Centre.

It is uncertain, at the present time, whether the NO2 concentration is solely due to vehicle

emissions or whether any industrial source influences are occurring at this site.

Further work will need to be carried out as part of a Third Stage Review & Assessment

in this area.

5.6 Results of Modelling of Industrial Sources

Currently we have targeted via the First Stage Review & Assessment, that Blue Circle Cement,

Western Solvents, Premiere Environmental and Wessex Incineration have the potential to emit

significant concentrations of NO2.

After thorough consultation with the Environment Agency, who regulate all of these processes,

the Environment Agency are confident that significant concentrations of NO2 shall not be

emitted from Western Solvents, Premiere Environmental or Wessex Incineration.

Western Solvents and Premiere Environmental, do not recover oil, only solvents. The only

potential emissions of NO2 from these two premises is via their own heating systems. The

heating systems are small and, therefore, emissions of NO2 are considered insignificant.

Wessex Incineration is approximately 4 km away from any significant locations within the West

Wiltshire District. Unfortunately, due to the small size of the stacks (less than 20m) an

assessment under the Environment Agency guidance GN24 cannot be carried out. However, the

Environment Agency have carried out a comparative study based on modelling data at another

similar process in Dimmer, near Castle Carey, this has revealed that NO2 emissions are

insignificant.

This leaves Blue Circle Cement as the only process with the potential to emit significant

quantities of NO2. Recently the site underwent a trial using tyres as a source of fuel. The results

of this trial are still awaited.

As part of the trial, Blue Circle Cement have been required to carry out a modelling study of

emissions and their impacts on the environment both with and without tyres.

This information is likely to be available in March 2000. No further work can be carried out,

until this information is received.

5.6.1 Conclusion

It is possible that emissions from Blue Circle Cement, Westbury, could be significant.

As part of our Third Stage Review & Assessment a further assessment of this process

shall be carried out.


ENVR44.TEC 37


The modelling information obtained from DMRB and AEOLIUS predicts that there will be

potential breaches of both NO2 objectives by the end of 2005. However, when the results from

the models are compared with the results from the NO2 diffusion tube surveys, the

concentrations measured via the diffusion tubes were much lower than those predicted via the

models. This indicates that the models do tend to overestimate. In this case the monitored NO2

data should be used as it is more accurate than predictive models which are based on

calculations.

Predicted NO2 concentrations for 2005 based on the NO2 diffusion tube data obtained in 1999

indicate that breaches of the annual mean objective could be exceeded in County Way,

Trowbridge and Masons Lane, Bradford on Avon.

In Westbury, we have carried out monitoring using an automatic chemiluminescent analyser and

passive diffusion tubes. For Warminster Road, Westbury the passive diffusion tube gave an

annual mean concentration of 46 g/m3. An 8 month mean using the automatic analyser gave a

concentration of 90 g/m3. It should be noted that diffusion tubes do have an accuracy of

+/- 25%, however, the 8 month mean concentration using the automatic analyser will have been

strongly influenced by the abnormally high concentrations achieved during September and

October 1999. In Westbury these issues need to be considered further.

West Wiltshire shall be moving to a Stage Three Review & Assessment process for the

following areas due to the fact that it cannot be ruled out that significant emissions of NO2 are

being released:-


County Way, Trowbridge Traffic related

Masons Lane, Bradford on Avon

Blue Circle Cement - Industrial Source


ENVR44.TEC 38

6 Second Stage Review & Assessment of Sulphur Dioxide

6.1 Introduction

The Authority will need to carry out a Third Stage Review & Assessment of sulphur dioxide

(SO2) if the Second Stage Review & Assessment indicates that there is significant risk of the

objectives being exceeded by the end of 2004 for the 1 hour and 24 hour means and by the end

of 2005 for the 15 minute mean objective.


quantities of SO2 being released via the following sources:-


Premiere Environmental Ltd, Chemical Road, West Wilts Trading Estate, Westbury, (an oil

and solvent recovery process).

Novacast Ltd, Station Approach, Melksham.

Additionally, a planned development to carry out a solvent recovery process had been notified to

this Authority. This process is called Western Solvents Ltd, Brook Lane Industrial Estate,

Westbury, and was authorised by the Environment Agency in December 1999.


The Review & Assessment: Pollutant Specific Guidance (LAQM - TG 4 (00)) states that to

assess for emissions of SO2 from industrial sources, predictive modelling studies should be

carried out using the Environment Agency's “Guidance for Estimating the Air Quality Impact of

Stationary Sources (GN24)”.

West Wiltshire District Council has contacted the Environment Agency, who authorise all the

processes except for Novacast Ltd, in order to gain information about SO2 emissions from the

The Government has adopted a 15 minute mean of 266 g/m3

(100ppb) as an air quality

standard for sulphur dioxide. The objective is that the standard is to be achieved as a 99.9th

percentile (this is equivalent to no more than 35 exceedances in a year) by the end of 2005. A

new 1 hour mean objective of 350 g/m3

(132ppb) to be exceeded no more than 24 times a

year (99.7th

percentile) and a new 24 hour mean objective of 125 g/m3

(47ppb) to be no more

than three times per year (99th

percentile) have been adopted as additional objectives to be

achieved by the end of 2004.

The focus of the Authority's Review and Assessment for the 24 hour objective for sulphur

dioxide should be at non-occupational, near ground level, outdoor locations where the public

might reasonably be exposed for a substantial part of the day. This would include such

locations as schools, housing and hospitals.

For the 1 hour and 15 minute objectives, the focus should include any non-occupational, near

ground level, outdoor locations where a member of the public might be exposed over the

relevant averaging period. This could include a playing field downwind of a point source

(industrial source).


ENVR44.TEC 39

processes. We have been informed that Premiere Environmental Ltd and Western Solvents Ltd

operate only solvent recovery processes, no oil recovery is carried out at either site.

Each site does, however, have gas oil fired heating systems, but the throughput of each is

considered to be negligible in terms of SO2 emissions. A Third Stage Review & Assessment

will, therefore, not be considered for these two processes.

Blue Circle Cement carried out a tyre burning trial in 1999. Modelling of the impact that the

process has on SO2 emissions is being carried out by Blue Circle Cement at the request of the

Environment Agency. This report is expected in March 2000 and the results will be forwarded

to this Authority for our consideration.

An assessment has not been carried out in accordance with the GN24 methodology. The impact

of SO2 emissions from Blue Circle Cement will be assessed as part of the Third Stage Review &

Assessment process.

With regard to Novacast Ltd, the First Stage Review & Assessment report indicated that SO2

emissions could be released via the oil fired furnaces at the site. After careful consideration, the

SO2 emissions are considered trivial and unlikely to give rise to significant SO2 releases due to

their very low throughputs.

6.3 Monitoring Data

In February 1999 a real time UV fluorescent SO2 analyser was installed in a roadside enclosure

in Warminster and Westbury to assess SO2 concentrations in the area. Unfortunately, the

analyser has not been working correctly due to various faults. It has now been removed for

repair and a replacement was installed in January 2000.

The data obtained from the analyser throughout 1999 cannot be relied upon and, therefore, no

data has been included in this report.

The data obtained since January 2000 will, however, be included in the Third Stage Review &

Assessment report.

6.4 Conclusion

West Wiltshire District Council will move to a Third Stage Review & Assessment for SO2 to

assess the impact that Blue Circle Cement might have on the population of Westbury and nearby

surrounding areas.

SO2 concentrations from the other industrial sources highlighted in the First Stage Review &

Assessment are considered negligible in view of their small boiler throughputs and site locations.


ENVR44.TEC 40

7.0 Second Stage Review & Assessment of PM10

The Government has adopted two air quality standards for fine particles

less than 10 microns in size (PM10). The objectives are 40 g/m3 as an

annual mean and 50 g/m3

as a fixed 24 hour mean to be exceeded no

more than 35 days per year (90th percentile). It is important to note that

these measurements are based on measurements which were carried out

using the European gravimetric transfer reference sampler or equivalent.

The objective is that the standards should be achieved by end 2004.

The focus of the Authority's Review & Assessment for PM10 should be

any non occupational, near ground level outdoor locations also the public

might be exposed for a substantial part of the day. Such locations

include background locations, roadside locations and other locations

where potentially significant groups might be exposed such as schools or

hospitals.

7.1 Introduction

The Authority will need to carry out a Third Stage Review & Assessment of PM10 if the Second

Stage Review & Assessment indicates that there is significant risk of the objectives being

exceeded by the end of 2004.


quantities of PM10 being released via the following sources:-


Cooper Avon Tyres, Bath Road, Melksham, (a rubber process).

Avon Rubber plc, Bath Road, Melksham, (a rubber process).

Wessex Incineration, West Woodlands, Frome, (an animal carcass incinerator).

10 mineral processes in the district of Mendip District Council.

County Way, Trowbridge.

7.1.1 Important Sources of PM10 on a National Level

Over the last two years a number of studies have been made on a national level into

determining the sources of PM10 emissions. In the UK there is a wide range of emission

sources that contribute to PM10 concentrations. The main source categories are as

follows:-

Primary Combustion Particles

Combustion processes such as from road traffic, industrial combustion processes and

power generation can emit particles directly into the atmosphere. These particles

tend to be less than 2.5 m and often well below 1 m in diameter.


ENVR44.TEC 41

Secondary Particles

These consist of particles formed in the atmosphere following their initial release in

the gaseous phase. These include sulphates and nitrates formed from emissions of

SO2 and NOx. These particles tend to be less than 2.5 m in diameter.

Course and Other Particles

These components comprise of emissions from a wide range of non-combustion

sources. They include resuspended dust from road traffic, construction and mineral

extraction processes, wind blown dust and soil and sea salt. These particles tend to

be less than 2.5 m in diameter.

Table 8 shows the approximate contributions to PM10 concentrations in 1998. This

information has been obtained from the Review & Assessment: Pollutant Specific

Guidance LAQM, TG4(00).

It is important to note the different source categories of PM10 emissions because

whilst some can be controlled at a local level, others such as SO2 and NOx emissions

which contribute to PM10 concentrations but come from other UK and overseas

sources may go largely uncontrolled and their impacts on PM10 at a local level will be

very meteorological dependent.

The focus of Local Air Quality Management should, therefore, be towards the control

of emissions at a local level. It is, therefore, important to ensure that the contribution

of local emission sources is correctly identified.


ENVR44.TEC 42

TABLE 8

Approximate Contributions to PM10 Concentrations 1998

Particle Type Source Location Main Source

Category

Main Source

Types

Typical

Contribution to

Annual Mean

Concentration

( g/m3

Gravimetric)

Course 2.5 -

10 m/m3

Immediate local

(very close)

Traffic

Resuspended dusts

and tyre wear

1-6

Industry

Fugitive dusts

Stock piles

Quarries

Construction

Variable

Urban background

Traffic

Resuspended dusts

and tyre wear

1-4

Industry

Fugitive dusts

Stock piles

Quarries

Construction

0.5-2

Regional

(including distant

sources)

Natural

Resuspended

dust/soil

Sea Salt

Biological

2-3

1-2

1

Fine

< 2.5 m

Immediate local

(very close)

Traffic

Vehicle exhaust

1-6

Industry

Combustion

Industrial processes

Variable

Domestic

Coal combustion

Variable

Urban background

Traffic

Vehicle exhaust

1-4

Industry

Combustion

Industrial processes

0.5-2

Domestic

Coal combustion

Variable

Regional

(including distant

sources)

Secondary

Power stations

6-16

Primary

(Europe)

Vehicles

Combustion

processes

1-2

Natural Sea Salt 0.5-1


ENVR44.TEC 43



The Review & Assessment: Pollutant Specific Guidance (LAQM: TG4(00)) states that

to assess for emissions of PM10 from industrial sources, predictive modelling studies

should be carried out. Predictions of PM10 concentrations should be carried out using the

Environment Agency's “Guidance for Estimating the Air Quality Impact of Stationary

Sources (GN24)”.


The Review & Assessment: Pollutant Specific Guidance (LAQM TG4(00)) states that to

assess for significant emissions of PM10 from traffic the Design Manual for Roads and

Bridges (DMRB) should be used. This is a screening model and more detailed

information is contained in paragraph 2.2.1 of this report.

7.3 Results with regard to Industrial Emissions

Currently we have targeted via the First Stage Review & Assessment that Blue Circle Cement,

Cooper Avon Tyres, Avon Rubber plc, Wessex Incineration and ten mineral processes in

Mendip District Council have the potential to emit significant quantities of PM10. Each process

is discussed in more detail.

7.3.1 Blue Circle Cement, Westbury

The Environment Agency who regulate this process have been contacted with a view to

predicting PM10 concentrations from the operations at the site. Recently the site

underwent a trial using tyres as a source of fuel. The results of this trial are still awaited.

As part of the trial, Blue Circle Cement have been required to carry out a modelling

study of emissions and their impacts on the environment both with and without tyres.

This information is likely to be available in March 2000. No further work can be carried

out until this information is received. It is possible that PM10 emissions from Blue Circle

could be significant. A further assessment of this process shall be carried out as part of

the Third Stage Review & Assessment.

7.3.2 Cooper Avon Tyres, Melksham

This is a rubber process which is regulated by West Wiltshire District Council. As a

rubber process it has the potential to emit significant amounts of PM10 from its

operations.

It is likely that the main potential releases of PM10 from this process would be from

fugitive sources. Modelling using the Environment Agency GN24 guidance has not

been used due to the problems in accurately modelling fugitive emissions.

This matter shall be assessed further as part of the Stage Three Review & Assessment.


ENVR44.TEC 44

7.3.3 Avon Rubber plc

In late 1999 this process moved its operations from Bath Road, Melksham, to two sites,

one on the West Wilts Trading Estate, Westbury, and the other at Hampton Park West,

Semington Road, Melksham. These premises have been purposely built for Avon

Rubber plc and incorporate “state of the art” technology.

Both processes are authorised by West Wiltshire District Council under LAPC, but only

the Westbury site is a rubber process.

It is believed that no significant fugitive releases of PM10 will arise from either of these

premises.

As part of their commissioning, the company will be required to carry out monitoring of

emissions. Once this information is obtained, then we will be in a position to predict

whether PM10 emissions are significant. This information will be contained in the Third

Stage Review & Assessment.

7.3.4 Wessex Incineration, West Woodlands, Nr Frome

The Environment Agency who regulate this animal carcass incineration process have

been contacted with a view to determining whether emissions from this process will give

rise to significant releases of PM10 to residents of West Wiltshire. No modelling work

has been carried out by them. It is their belief that significant releases of PM10 will not

be produced or give rise to emissions of PM10 that will significantly affect residents in

West Wiltshire.

To back up this argument, the Environment Agency have carried out modelling, using

the ADMS urban model, of a similar process at Dimmer near Castle Carey, Somerset,

and they predicted little PM10 releases.

The Environment Agency GN24 model has not been used because the flues of the

process are less than 20 metres in height.

In the light of this information this process shall not be subject to any further assessment

of air quality.

7.3.5 Ten Mineral Process in Mendip District Council's Area

All of these processes are regulated by Mendip District Council. Any PM10 emissions

released are likely to be from fugitive sources. The Review & Assessment: Pollutant

Specific Guidance (LAQM TG4 (00)) states that dust emissions from these types of

processes are likely to be within the larger particle size fractions and will, therefore, fall

out from the atmosphere rapidly. Therefore, properties further than 400 metres away

from the source are not likely to be significantly affected by PM10 emissions.

Additionally, the DETR “Assistance with Review & Assessment of PM10 concentrations

in relation to the proposed EU stage 1 limit values” report states that local authorities

should not consider sources which lie a distance of 5 km or greater from the nearest

sensitive receptor.

In the light of this information and the fact that the nearest West Wiltshire receptor is 6

kilometres away from the nearest quarry. No further assessment shall be made and PM10

emission can be deemed to be insignificant with regard to receptors in West Wiltshire.


ENVR44.TEC 45


7.4.1 DMRB

Estimations of the annual mean PM10 concentrations for the end of 2004 were prepared

using the DMRB methodology. A DMRB spreadsheet provided by Stanger Science and

Environment was used for the assessment. The results are shown in Table 9. Appendix

1 provides the results in full. It should be noted that only County Way, Trowbridge, was

thought to possibly create significant PM10 emissions in the First Stage Review &

Assessment. However, in the light of new PM10 advice both produced in the Review &

Assessment: Pollutant Specific Guidance (LAQM TG4(00)) and the DETR” Assistance

with Review & Assessment of PM10 concentrations in relation to the proposed EU Stage

1 Limit Values” report, other roads have been considered.

Bearing in mind the importance of distinguishing between the primary component and other PM10 components,

the overall annual mean figure in the DMRB model incorporates a background PM10 concentration in 2004 of

21.3 g/m3. This figure has been obtained from the Internet (http: //www.aeat.co.uk/netcen/airqual/). To

determine the primary component (ie the predicted PM10 emission directly from road traffic), the background

concentration should be subtracted from the total annual mean concentration.

TABLE 9

Results of DMRB Model

Site Annual Mean PM10

2004 ( g/m3)

90th

percentile PM10

2004 ( g/m3)

A361 County Way, Trowbridge

24.35

44

A350 Warminster Road, Westbury

23.67

42

A350 High Street, Semington

23.75

43

Town Bridge, Bradford on Avon

(5% HDV)

21.16

38

For the purpose of the DMRB model, the 90th

percentile (equivalent to 35 exceedances per year) is determined

by multiplying the estimated annual mean by 1.79.

The Town Bridge, Bradford on Avon, has a weight limit of 17 tonnes. In reality this means that there is a very

low percentage of HDV's passing through the town. In view of the fact that no HDV data was available for the

Town Bridge from Wiltshire County Council, a 5% HDV mix has been used.

All traffic count data has been derived from the Travel Report Wiltshire 1998. In the case of Warminster Road,

Westbury, no data was contained within the Travel Report Wiltshire 1998, and so count data from 1996 has

been used.

For the purposes of all the calculations a high growth factor has been used, in view of the fact that West

Wiltshire is recognised as experiencing high growth.


ENVR44.TEC 46

7.4.2 AEOLIUS

The town of Bradford on Avon is made up of very narrow canyon streets. To make a

more accurate assessment of PM10 emission the AEOLIUS model was used. In

determining predictions of the PM10 concentrations using AEOLIUS model, the

information contained in table 4 has been used. It should be noted that a proposed major

development of a currently redundant factory in the heart of the town of Bradford on

Avon is being considered by this authority's development control section. If permission

is granted then traffic flows through the town may be affected.

Average hour speeds have been determined by using a moving car observer method..

Average hourly flow data has been estimated by multiplying the peak hour flow

information by a factor of 10. This provides a conservative estimate on which to base

our information.

Estimations of the annual mean in canyon streets for 2004 were prepared using

AEOLIUS. The results are shown in Table 10. Appendix 2 provides the results in full.

TABLE 10 Results of AEOLIUS Model for PM10

Site

1998 Annual Mean

PM10 ( g/m3)

1998 90th

Percentile

PM10 ( g/m3)

2004 Annual Mean

PM10 ( g/m3)

2004 90th

Percentile

PM10 ( g/m3)

Masons Lane

1998 traffic data

36.26

64.9

Market Street

1998 traffic data

39.11

70.0

Silver Street

1998 traffic data

37.14

66.48

Masons Lane using

2005 predicted traffic

data without

development*

30.97

55.44

Market street using


data without

development*

32.58

58.32


predicted traffic data

without development*

31.47

56.33

Masons Lane using


data with development*

31.14

55.74

Market Street using


data with development*

32.77

58.66


predicted traffic data

with development*

33.41

59.80

* Denotes that when determining the predicted 2004 concentrations, traffic data for 2005 has been used


ENVR44.TEC 47

7.4.3 Discussion

None of the roads modelled using the DMRB model appear likely to exceed the air

quality objectives by 2004. However, the sites studied using the AEOLIUS model do

appear to be likely to exceed the 90th

percentile of annual means, but not the annual mean

objective.

The predicted concentration of PM10 in Bradford on Avon do not appear to be

significantly affected by the proposed development. The concentrations of PM10 are in

exceedance of the 24 hour mean objective in either case.

It should be noted that when determining the predicted 2004 concentrations, traffic data

for 2005 has been used. This may have influence on the outcome of the model, but

bearing in mind that traffic growth is likely to be higher in 2005 than 2004, this

represents a worst case situation.

7.4.4 Conclusion

From the traffic emission modelling carried out using DMRB and AEOLIUS models, it

appears that the sites in Trowbridge, Westbury and Semington are unlikely to be in

exceedance of the air quality objective by the end of 2004. However, the canyon effect

of the streets in Bradford on Avon, does appear to have an influence on dispersion of

PM10. The predicted concentrations of PM10 in Masons Lane, Market Street and Silver

Street indicate that exceedance of the 24 hour mean objective will be exceeded at the end

of 2004.

More work needs to be carried out in this area.

7.5 Results of Automatic Monitoring for PM10 Warminster Road, Westbury

Since 6 February 1999 we have been monitoring for PM10 using a BAM 1020 PM10 analyser.

Information about this analyser can be found in paragraph 2.2.2.1.1 of this report.

Monitoring over twelve months has provided us with a suitable amount of data on which to base

our conclusions. We have obtained a 91% data capture. The Review & Assessment: Pollutant

Specific Guidance (LAQM TG4(00)) states that a minimum of 90% data capture should be

achieved.

Graphs showing the 24 hour mean PM10 concentrations for February 1999 to January 2000 are

contained in Appendix 14 of this report. Table 11 shows a summary of the PM10 monitoring

data.

The data for 1999 has shown that the annual mean objective of 40 g/m3 is not being exceeded.

With regard to the 24 hour mean objective, the site exceeded the 50 g/m3 limit on 34 days.

This is just below the 35 day limit.

In accordance with the Review and Assessment: Pollutant Specific Guidance (LAQM TG4 (00))

a prediction of the 2004 PM10 concentrations has been determined. When using the

methodology the data has to be divided into the separate source categories of primary, secondary


ENVR44.TEC 49

TABLE 11

Summary of PM10 Monitoring Data (Westbury)

Feb

99

March

99

April

99

May

99

June

99

July

99

Aug

99

Sept

99

Oct

99

Nov

99

Dec

99

Jan

00

Total Standard

Monthly Mean

( g/m3) gravimetric

24

34

33

44

27

25

29

34

30

27

19

31

30

40

Number of Exceedances

2

5

3

8

0

0

3

5

4

0

0

4

34

35


ENVR44.TEC 50

and course particulate. Each must be treated separately. As far as local emissions are

concerned, it is only the primary component that is of significance.

The complete methodology is shown in Appendix 15 of this report.

In summary, the predicted total PM10 for 2004 is 27.28 g/m3(gravimetric). The primary

contribution is predicted to be 6 g/m3 (gravimetric).

7.5.1 Conclusion

In 1999 the PM10 concentrations in Warminster Road, Westbury, were below the

annual mean objective. However, on 34 days out of the year the PM10 concentration

exceeded the 24 hour mean objective concentration. The new standard allows 35

exceedances therefore in 1999 we were within the objective level. In order to

clarify the PM10 concentrations further we shall continue to monitor PM10 at this site.

Appendix 15 shows the calculation methodology used to correct the monitoring

data to 2004. The calculation predicts that in 2004 the annual mean PM10 concentration

will be 27.28 g/m3

(gravimetric), the primary contribution being 6 g/m3 (gravimetric).

This is well below the Air Quality objective concentration.


West Wiltshire District Council shall be moving to a Stage Three Review &

Assessment process for the following areas:-

Blue Circle Cement

Cooper Avon Tyres

Avon Rubber plc

Additionally, we shall continue monitoring PM10 in Warminster Road, Westbury

and an indicative survey of PM10 shall be carried out in Masons Lane,

Bradford on Avon, to assess the PM10 concentrations along this road.


ENVR44.TEC 51

8.0 Second Stage Review & Assessment of Lead

The Government has adopted an annual mean of 0.5 g as an air quality

standard for lead, with an objective for the standard to be achieved by the

end of 2005. This standard and objective is expected to change when the

new Air Quality (England) Regulations 2000 are in force. There will be

two new standards and objectives, the first is an annual mean of 0.5

g/m3

to be achieved by the end of 2004, and the second is a lower air

quality objective of 0.25 g/m3 to be achieved by the end of 2008.

The focus of the Authority's Review and Assessment for lead should be

at non-occupational, near ground level outdoor locations where the

public might reasonably be expected to be exposed. This would include

background locations, roadside locations and schools or hospitals.

8.1 Introduction

This Authority will need to carry out a Third Stage Review & Assessment of lead if the Second

Stage Review & Assessment indicates that there is significant risk of the objectives being

exceeded by the end of 2004 or 2008 for the lower standard.


quantities of lead being released from an aluminium and aluminium alloy process carried out at

Novacast Ltd, Station Approach, Melksham.


The Review & Assessment: Pollutant Specific Guidance (LAQM - TG4(00)) states that to

assess for emissions of lead from industrial sources monitoring or modelling can be carried out.

The model used should be the Environment Agency G24 guidance.

In this particular case the stacks are less than 20m in height and, therefore, the G24 model could

not be used.

The process is regulated by West Wiltshire District Council as a Part B aluminium and

aluminium alloy process. The only lead used in the process is that contained in the gun metal,

this represents a very small percentage of lead. The type of gun metal used is LG1 and LG4.

LG1 contains a maximum of 6% lead and LG4 a maximum of 3.5% lead. The annual use of gun

metal used in the process is considered trivial.

It is, therefore, appropriate to assume that emissions of lead will be insignificant from this

process due to the trivial amount of lead used.

8.3 Conclusion

West Wiltshire District Council are satisfied that emissions of lead are insignificant. Therefore,

no further Stage 3 Review & Assessment will be required.


ENVR44.TEC 52

9.0 Summary of Assessments

This report has highlighted the comprehensive information on predicted concentrations of carbon

monoxide. 1,3 - Butadiene, nitrogen dioxide, sulphur dioxide, PM10 and lead. This information has been

based on automatic monitoring data, diffusion tube monitoring data and predictive modelling studies.

As a result of the second stage review and assessment we have confirmed that releases of carbon

monoxide or lead are not present in significant quantities within the West Wiltshire district.

However, significant releases that could affect a person over the relevant exposure period can not be

ruled out for 1,3 - Butadiene, nitrogen dioxide, sulphur dioxide and PM10.

West Wiltshire District Council shall therefore be moving onto a stage 3 review and assessment for

these pollutants. This will involve automatic monitoring and more complex modelling of these

pollutants.

9.1 Recommendations for the third stage review and assessment

Continue automatic monitoring for PM10 and SO2 in Warminster Road, Westbury

Undertake automatic monitoring for NO2 and PM10 at relevant locations in Masons Lane

Bradford on Avon and County Way Trowbridge

Undertake a detailed study of 1,3 - Butadiene emissions in Melksham

Continue the NO2 diffusion tube survey in Westbury and Semington

Extend the NO2 diffusion tube survey in Westbury to account for more relative locations

Undertake sophisticated modelling of emissions from Blue Circle Cement, Cooper Avon

Tyres, Avon Rubber Plc, County Way Trowbridge and Masons Lane, Silver Street and

Market Street Bradford on Avon.


ENVR44.TEC 53

Glossary of Terms and Abbreviations

Term Description

1,3 - Butadiene A volatile aliphatic compound

AADT Annual average daily traffic flow

Accuracy A statistical method for measuring how well a set of data fits the

true value

ADMS Atmospheric Dispersion Modelling System

AEA Atomic Energy Authority

AEOLIUS An atmospheric dispersion model developed by the meteorological

office

AQMA Air Quality Management Area

AUN Automatic Urban Network

Background level The level of a substance (in this case gases and particulates) which

is normally present in an environment and which should be taken

into account when monitoring or measuring pollution

Calibration Determining the accuracy of an instrument and, if necessary,

correcting the reading of an instrument with a standard

Carbon Monoxide (CO) A gaseous pollutant formed during incomplete combustion of

carbonaceous fuel

Chemiluminescence The emission of absorbed energy as light during a chemical

reaction. The measurement of the light emitted can give a measure

of the concentration of one of the reactants if the other one is

known.

Chromatography A method of separating mixtures. The process is based on the

principle of adsorption, different chemicals adsorb at different

rates. From this a particular chemical can be isolated.

Concentration A method of defining an amount of a substance in a volume. In

this case air.

DETR Department of the Environment, Transport and the Regions

Diffusion Tube An adsorption tube used to measure specific pollutants

Dispersion Describes the way in which a pollutant spreads from its point of

emission and becomes diluted in atmosphere

DMRB Design Manuel for Roads and Bridges


ENVR44.TEC 54

EPAQS Expert Panel on Air Quality Standards

Gas Oil A liquid petroleum distillate having a viscosity and distillation

range between paraffin and light lubricating oil. It is in the same

boiling point range as diesel oil. It is often used for heating

purposes and has a relatively low sulphur content.

Gravimetric Method An analytical method based on weighing particulate matter

collected on a filter. Gravimetric methods are capable of high

accuracy, but are more time-consuming and require greater skill

than volumetric methods

Mean The average of a data set

mg/m3 Milligrammes per cubic metre

Model An air pollution mathematical model is a numerical simulation of

the emission, dispersion and chemical processes controlling

ambient pollutant concentrations.

NAMAS National Auditing Service

Nanogram (ng) A unit of mass equal to one thousandth of one millionth of a gram

(10-9

g)

NETCEN National Environment Technical Centre

Nitric Oxide (NO) The main oxide of nitrogen. It arises from the combination of

atmospheric nitrogen with oxygen which is created during high

temperature combustion and from industrial processes.

Nitrogen Dioxide (NO2) A pollutant which is created during high temperature combustion

and as a result of oxidation of nitric oxide in the presence of ozone

NOx Generic name for oxides of nitrogen and in air pollution terms

NOx implies NO and NO2

PM10 Particulate matter with a mean effective atmospheric diameter of

10 microns or less in size. The concern here is that it is these

particles that can penetrate deep into the lungs.

ppb Parts per billion

PPM Parts per million (ie the number of parts of the gaseous pollutant in

one million parts of air)

Rolling Average An average set of data over a consecutive time period where the

average moves in a continuous step

Sulphur Dioxide (SO2) A colourless gas mainly produced from the burning of sulphur

contained in fuels (ie coal and oil).

TEOM Tapered Element Oscillating Microbalance, a method of

monitoring for particulate matter


ENVR44.TEC 55

TSP Total suspended particulate

g/m3 Microgrammes per cubic metre

VOC Volatile Organic Compounds these are organic compounds that

evaporate easily


ENVR44.TEC 56

References

AEA Technology. (May 1999). UK Nitrogen Dioxide Network 1997. Prepared by NETCEN as part of the

DETR Air Quality Research Programme. Abingdon: AEA Technology.

Airborne Particulates Expert Group (APEG). (January 1999). Source Apportionment of Airborne Particulate

Matter in the United Kingdom. Prepared on behalf of the DETR, the Welsh Office, the Scottish Office and the

DoE Northern Ireland. ISBN 0-7058-1771-7.

Babb, C. (9 February 2000). Personal Communication.

Department of the Environment, Transport and the Regions (DETR). (1997). LAQM.G1(97) Framework for

the review and assessment of air quality. London: The London Stationary Office.

DETR. (1997). LAQM.G2 (97) - Developing local air quality action plans and strategies: the principal

considerations. London: The London Stationary Office.

DETR. (1997). LAQM. G3 (97) - Air quality and traffic management. London: The London Stationary Office.

DETR. (1997). LAQM. G4 (97) - Air Quality and Land Use Planning. London: The London Stationary

Office.

DETR. (1998). LAQM. TG1 (98) - Monitoring for air quality review and assessments. London: The London

Stationary Office.

DETR. (1998). LAQM. TG3 (98) - Selection and use of dispersion models. London: The London Stationary

Office.

DETR. (1998). LAQM. TG4 (98) - Review and assessment: Pollutant specific guidance. London: The

London Stationary Office.

DETR. (5 November 1999). LAQM.G1 (00) - Draft Revised Guidance, Framework For Review and

Assessment of Air Quality.

DETR. (5 November 1999). LAQM.G3 (00) - Draft Revised Guidance, Air Quality and Transport.

DETR. (5 November 1999). LAQM. G4 (00) - Draft Revised Guidance, Air Quality and Land Use Planning.

DETR. (10 December 1999). LAQM. TG1 (00) - Draft Revised Guidance, Review and Assessment:

Monitoring Air Quality.

DETR. (16 December 1999). LAQM. TG2 (00) - Draft Revised Guidance, Review and Assessment:

Estimating Emissions.

DETR. (December 1999). LAQM. TG3 (00) - Review and assessment: Selection and use of dispersion models,

Consultation Draft.

DETR. (December 1999). LAQM. TG4 (00) - Review and assessment: Pollutant Specific Guidance,

Consultation Draft.

DETR. (January 2000). The Air Quality Strategy for England, Scotland, Wales and Northern Ireland. Cm

4548. United Kingdom: HMSO.


ENVR44.TEC 57

Environment Agency. (November 1998). National Centre for Risk Analysis & Options Appraisal, Guidance

for Estimating the Air Quality Impact of Stationary Sources. GN4.

Environment Act 1995 Chapter 25 (Part IV). London: HMSO

Highways Agency. (May 1999). Design Manuel for Roads and Bridges, Volume 11 section 3 Part 1 - Air

Quality - Annex 1 Localised Air Quality Assessment. London: The Stationary Office.

Loveday, T. J. (20 December 1999). Personal Communication.

Stanger Science and the Environment, Air Quality Consultants and NETCEN. (March 1999). Assistance with

the review and assessment of PM10 concentrations in relation to the proposed EU Stage 1 limit values.

Croydon: Stanger Science and Environment.

Wiltshire County Council. (1996). Travel Report 1996.

Wiltshire County Council. (1997). Travel Report 1997.

Wiltshire County Council. (1998). The Travel Report Wiltshire 1998.

LOCAL AIR QUALITY MANAGEMENT - Wiltshire · 2012-08-03 · LOCAL AIR QUALITY MANAGEMENT SECOND...

Documents

Transcript of LOCAL AIR QUALITY MANAGEMENT - Wiltshire · 2012-08-03 · LOCAL AIR QUALITY MANAGEMENT SECOND...