Guidance on the Assessment of Mineral Dust Impacts for Planning

Assessment of Disamenity Dust Impactsusing S-P-R Qualitative Approach

Jon PullenRPS Planning & Development

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1. Introduction

Potential Effect Causative Impacts

Effects on people Health Exposure by inhalation to dust suspended in the air (PM10 fraction)

Disamenity Deposition of dust out of the air and accumulation on surfaces, leading to soling / staining

Effects on ecologically-sensitive habitats Deposition of dust out of the air and accumulation on flora, etc

• The guidance covers three potential effects from quarry dust:

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Terminology• Amenity: “A positive element or elements that contribute to the overall

character or enjoyment of an area. For example, open land, trees, historic buildings and the inter-relationship between them, or less tangible factors such as tranquillity.” (www.planningportal.co.uk/directory_record/101/amenity)

• Disamenity: The government Planning Portal does not define disamenity, but its literal meaning would be “impaired amenity” and from its definition of amenity could be considered to be a negative element or elements that detract from the overall character or enjoyment of an area.

• Impacts & Effects - The terms ‘impacts’ and ‘effects’ are often used interchangeably in Environmental Statements and Dust Assessments. In this document the term ‘impact’ has been used to describe a change in suspended particulate matter (PM) concentration or dust deposition and ‘effect’ to describe the consequences of any impacts such as to human health or disamenity

1. Introduction (continued)

150m 200m100m50m >1 km

PM10-30

PM10PM>30

• Transport of dust from source to receptor:o Source – release of dust at quarry.o Pathway – travels through the air in a particular direction and for a given

distance to…o Receptor

• If all three elements are present in an unbroken chain then dust exposure/impact (deposition and accumulation on surfaces) can occur• May result in an adverse effect (disamenity)

Dust suspended in air

1. Introduction (continued)

Dust deposited on surfaces

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I will cover…..2. Recommended content of the

assessment3. The qualitative S-P-R approach4. The Steps in the assessment5. Example

1. Introduction (continued)

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2. Recommended Content of the Assessment

v. A prediction, using appropriate assessment tools, of the likely PM10 and dust deposition impacts and resulting effects (on health, amenity, and/or ecology) at relevant sensitive receptors, and taking into account the following:

a) The likely magnitude of dust emissions (after control by measures incorporated into the scheme); b) the likely meteorological characteristics at the site;c) the dispersion and dilution afforded by the pathway to the receptors, taking into account distance, orientation, local terrain and features, and other relevant factors;d) the sensitivity of the receptors to disamenity, health and/or ecology effects; ande) any likely cumulative interactions.

vi. The residual PM10 and dust deposition impacts and their disamenity, health and/or ecology effects;vii. A conclusion on the significance of the overall residual air quality effect, i.e. whether “significant” or “not significant”;viii. Where the effects are assessed as significant, appropriate further mitigation (including modification of site design) and control measures that could allow the proposal to proceed without causing significant adverse effects; and....

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3. The Qualitative S-P-R Approach

• Why? – The collective view of the IAQM Working Group is

that it is currently inappropriate to use a quantitative modelling approach to predict the impact in most cases.

– This is primarily due to a lack of UK derived emission factors for minerals sites that could be used for modelling.

• How?– The guidance recommends the dust impact at

relevant receptors should be predicted using a qualitative assessment based clearly on the S-P-R concept.

For the appropriate assessment tool, the guidance recommends a qualitative risk-based approach as usually being sufficient for assessing disamenity (and also the ecological) effects of deposited dust

4. The Steps in the Assessment

Risk of Dust ImpactReceptor Sensitivity

Low Sensitivity Medium Sensitivity High Sensitivity

High Risk of Dust Impact Slight Adverse Effect Moderate Adverse Effect Substantial Adverse Effect

Medium Risk of Dust Impact

Negligible Effect Slight Adverse Effect Moderate Adverse Effect

Low Risk of Dust Impact Negligible Effect Negligible Effect Slight Adverse Effect

Negligible Risk of Dust Impact

Negligible Effect Negligible Effect Negligible Effect

• The fundamental matrix of exposure v effect similar to those in other S-P-R based guidance.

• Describes magnitude of disamenity effects for receptors of different sensitivities receiving different deposition impacts.

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4. The Steps in the Assessment (cont)

• Receptor sensitivities are categorised (Low, Medium or High) using same criteria as IAQM construction dust guidance.

• Categorising the dust deposition impact on each receptor is more challenging. This needs to be obtained by considering, together, the Residual Source Emissions term and the Pathway Effectiveness.   

Residual Source Emissions

   Small Medium Large

Pathway Effectiveness

Highly effective pathway Low Risk Medium Risk High Risk

Moderately effective pathway Negligible Risk Low Risk Medium Risk

Ineffective pathway Negligible Risk Negligible Risk Low Risk

• It is this matrix, which delivers the dust impact, that requires “calibration” for quarries.

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• The calibration of this matrix for quarries is where the IAQM document really makes a contribution .

• Gives guidance on how these two terms should be categorised, drawing on the collective experience of the Working Group. Factors covered:

4. The Steps in the Assessment (cont)

a) Magnitude of Residual Source Emissions termi. The activities being undertaken (blasting, crushing, screening, etc.);ii. The types and properties of the materials involved;iii. The size of the site / area of land worked (hence the quantities of materials involved and

the number of vehicles and plant etc.); iv. The durations and frequencies of the activities;v. The likely effectiveness of the dust control measures incorporated into the design of the

submitted development scheme; vi. Other mitigation measures applied to reduce or eliminate dust; andvii. the meteorological conditions that can promote or inhibit the raising of dust at the source

(high winds and rainfall, respectively). b) Pathway Effectiveness term

viii. The distance between dust sources and receptorsix. Orientation of receptors relative to the prevailing wind directionx. Terrain and physical features.

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4. The Steps in the Assessment (cont)

• Various schemes have been used by IAQM members to determine the Source term and the Pathway term. Appendix 3 has an illustrative example.

• The example given for determining the Pathway Effectiveness term…

a) first categorises the frequency of potentially dusty winds as follows:

Frequency Category Criteria

Infrequent Frequency of winds (>5 m /s) from the direction of the dust source on all days in the year are less than 5%

Moderately frequent The frequency of winds (>5 m/s) from the direction of the dust source on all days in the year are between 5% and 12%

Frequent The frequency of winds (>5 m/s) from the direction of the dust source on all days in the year are between 12% and 20%

Very frequent The frequency of winds (>5 m/s) from the direction of the dust source on all days in the year are greater than 20%

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4. The Steps in the Assessment (cont)

b) each receptor’s distance from the dust source is then categorised based on the criteria in the table below:

Category Criteria

Distant Receptor is between 200 and 400m from the dust source

Intermediate Receptor is between 100 and 200m from the dust source

Close Receptor is less than 100 m from the dust source

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4. The Steps in the Assessment (cont)

• The Pathway Effectiveness term then is classified using the Frequency of Potentially Dusty Winds and the Receptor Distance from Source, as follows:

Frequency of potentially dusty winds

Infrequent Moderately frequent Frequent Very frequent

1.1 Receptor Distance Category

Close Ineffective 1.2 Moderately Effective Highly Effective Highly Effective

Intermediate Ineffective 1.3 Moderately Effective

1.4 Moderately Effective Highly Effective

Distant Ineffective 1.5 Ineffective 1.6 Moderately Effective

1.7 Moderately Effective

Risk of Dust ImpactReceptor Sensitivity

Low Sensitivity Medium Sensitivity High Sensitivity

High Risk of Dust Impact Slight Adverse Effect Moderate Adverse Effect Substantial Adverse Effect

Medium Risk of Dust Impact

Negligible Effect Slight Adverse Effect Moderate Adverse Effect

Low Risk of Dust Impact Negligible Effect Negligible Effect Slight Adverse Effect

Negligible Risk of Dust Impact

Negligible Effect Negligible Effect Negligible Effect

4. The Steps in the Assessment (cont)

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5. Example

Example of Summary of Dust Disamenity Effects at Specific Receptors

Ref Receptor details and location

Location relative to

nearest dust source

Residual Source

Emissions 

Pathway Effectiveness

Dust Impact Risk

 

Receptor Sensitivity

 

Magnitude of Dust Effect

R1Rock House

Green Lane (Residential)

220m “downwind” of mineral extraction

Medium Moderately Effective Low Risk High

Slight Adverse

Effect

R2 Wood Cottage

Kings Road

(Residential)

300m “upwind” of haul road

Large Ineffective Low Risk HighSlight

Adverse Effect

R4 Village Store and Post Office

(Commercial / Retail)

170m “downwind” of mineral processing

LargeModerately Effective Medium Risk Medium

Slight Adverse

Effect

R5 The Rec

(Playing Fields)

150m “upwind” of stockpiles

Medium Moderately Effective Low Risk Low Negligible

Effect

R6

Public footpath

50m “downwind” of mineral processing

Large Highly Effective High Risk LowSlight

Adverse Effect

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Significance of Effects

• Where the overall effect is greater than “slight adverse”, the effect is likely to be considered significant.

• This is a binary judgement: either it is “significant” or it is “not significant”.

• Concluding that an effect is significant should not mean, of itself, that a development proposal is unacceptable and the planning application should be refused; rather, it should mean that careful consideration needs to be given to:– the consequences; – the scope for securing further mitigation; and – the balance with any wider environmental, social and economic

benefits that the proposal would bring.

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Questions?