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PM10 & Dust Reduction With Distance

Ian Stone

IAQM Meeting24th May 2016

London

Advance Environmental

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PM10 & Dust Reduction With Distance

Advance Environmental

Dust that has become suspended in the air will dilute, disperse and deposit from the air with the resultant airborne PM concentration decreasing rapidly as a function of distance from its source.

In general, smaller particles have the potential to be entrained within airflow for longer, thereby dispersing over a wider area.

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PM10 & Dust Reduction With Distance

Advance Environmental

The following graphs show the fall-off in dust deposition and PM10 concentrations with distance from the source on mineral sites.

The monitoring data were obtained from members of the IAQM Mineral Guidance Working Group.

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PM10 & Dust Reduction With Distance

Advance Environmental

It must be emphasised that these graphs are generic, have been provided in the absence of robust published data and are not intended to be used in isolation from the source-pathway receptor assessment approach for each distinct site and its receptors.

Note that distances are from potentially ‘dust generating activities’ rather than the site boundary.

Examples of activities include extraction and processing areas, stocking areas or haul roads.

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Dust Deposition

Advance Environmental

The following graphs are a generic illustration of dust deposition rates as a function of distance for a range of granitic quarries in the UK.

The dust deposition data were collected monthly using Frisbee dust deposit gauges over a period of several years.

The data were derived from monitoring undertaken in the vicinity of a number of quarries, and do not take into consideration individual topographic and directional factors.

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Long-term Mean Rates of Dust Deposition - Reduction With

Distance

Advance Environmental

0 100 200 300 400 500 600 700 8000

50

100

150

200

250

300

Granitic quarries: Mean rate of dust deposition as a function of distance from quarry operations

Distance from nearest source (m)

Mea

n ra

te o

f dep

ositi

on (m

g/m

2/da

y)

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Maximum Monthly Rates of Dust Deposition - Reduction

With Distance

Advance Environmental

0 100 200 300 400 500 600 700 8000

100

200

300

400

500

600

700

800

Granitic quarries: Maximum monthly rate of dust deposition as a function of distance from quarry operations

Distance from nearest source (m)

Mea

n ra

te o

f dep

ositi

on (m

g/m

2/da

y)

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PM10 Reduction With Distance

Advance Environmental

The following graph represents gravimetric and equivalent PM10 measurements undertaken at a variety of distances from assorted mineral site categories (granitic, sand and gravel, limestone, opencast coal and clay).

Each data point represents the PM10 values for monitoring periods ranging from 4 months to annual means. These generic values show dispersion of PM10 concentrations as a function of distance from nearest potential sources.

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PM10 Reduction With Distance

Advance Environmental

0 100 200 300 400 500 600 7000

5

10

15

20

25

30

35

40

45

50

Mean gravimetric PM10 during periods of assessments vs distance from potential sources - various mineral types

Distance from nearest source (m)

Mea

n PM

10 (µ

g/m

3)

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PM10 Reduction With Distance

Advance Environmental

0 100 200 300 400 500 600 7000

5

10

15

20

25

30

Mean additional PM10 above nearest AURN urban / rural background during assessment periods vs distance from potential sources - various

mineral types

Distance from nearest source (m)

Addi

tiona

l mea

n PM

10 (µ

g/m

3)

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PM10 Reduction With Distance

Advance Environmental

0 100 200 300 400 500 600 7000

5

10

15

20

25

30

Mean additional PM10 above nearest AURN urban / rural background during assessment periods vs distance from potential sources - various

mineral types

Clay granitic limestone opencast coal sand & gravel Secondary aggregatesilica sand

Distance from nearest source (m)

Addi

tiona

l mea

n PM

10 (µ

g/m

3)

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PM10 & Dust Reduction With Distance

Advance Environmental

Typical Impacts with Distance

From the experience of the Working Group, adverse dust impacts from sand and gravel sites are uncommon beyond 250m, and beyond 400m from hard rock quarries, measured from the nearest dust generating activities

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PM10 & Dust Reduction With Distance

Advance Environmental

In the absence of other information it is commonly accepted that the greatest impacts will be within 100m of a source and this can include both large (>30µm) and small dust particles.

The greatest potential for high rates of dust deposition and elevated PM10 concentrations occurs within this distance.

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PM10 & Dust Reduction With Distance

Advance Environmental

Intermediate-sized particles (10 to 30µm) may travel up to 400m, with occasional elevated levels of dust deposition and PM10 possible.

Particles less than 10µm have the potential to persist beyond 400m but with minimal significance due to dispersion.