document history chapter 9 - agile energy

Thainstone Energy Park

9-1 Environmental Impact Assessment Report

Chapter 9: Air Quality

Document history Author Mervyn Keegan 22/05/2020

Checked Oliva Maguire 22/05/2020

Approved Andy Yuill 30/06/2020

Client Details

Contact Alf Robertson

Client Name Agile Energy Recovery (Inverurie) Ltd

Address 1 Marischal Square, Broad Street, Aberdeen, AB10 1BL

Issue Date Revision Details

B 10/07/2020 Final

Chapter 9 Air Quality

Contents Executive Summary 3

9.1 INTRODUCTION 4

Air Quality Impact Assessment Methodology 4

Relevant Legislation 5

Relevant Air Quality Limit Values 5

Air Dispersion Modelling Software 6

Air Dispersion Modelling Inputs 7

Overview 7

Proposed EfW Development Emission Rates 7

Building Downwash Effects 7

Receiver Locations 8

Time Averaging and Percentiles 10

Terrain Data 10

Surface Roughness & Land Use Characteristics 10

NOx to NO2 Chemistry 10

Proposed EfW Development Stack 11

Meteorological Data 12

9.2 ASSESSMENT OF SIGNIFICANCE OF POTENTIAL ENVIRONMENTAL EFFECTS 13

Describing the Impact: 13

Assessing Significance 13

9.3 EXISTING ENVIRONMENT 14

Air Quality Management Areas 14

Baseline Air Quality 14

Nitrogen Dioxide (NO2) 14

Particulate Matter (PM10 and PM2.5) 14

Sulphur Dioxide, Carbon Monoxide, Lead and 1,3-Butadiene 15

Ammonia 15

Metals 15

PCDD/Fs 15

Polycyclic Aromatic Hydrocarbons (PAH) 15

Background Maps 15

Background Concentrations used in the Air Quality Impact Assessment 15

NO2 15

PM10 15

9.4 AIR DISPERSION MODELLING RESULTS 16




Predicted Impacts on Human Receivers 16

9.5 DISCUSSION OF AIR DISPERSION MODELLING RESULTS HUMAN RECEIVERS 21

Nitrogen Dioxide (NO2) 21

Carbon Monoxide (CO) 21

Particulates (PM10 & PM2.5) 21

Sulphur Dioxide (SO2) 21

Volatile Organic Compounds (VOCs) as Benzene 22

Hydrogen Chloride (HCl) 22

Hydrogen Fluoride (HF) 22

Ammonia (NH3) 22

Metals 22

Dioxins, Furans and Dioxin-like PCBs 23

9.6 PREDICTED IMPACTS AT ECOLOGICAL RECEIVERS 23

9.7 ODOUR CONTROL MEASURES 28

Odour Guidelines 28

9.8 PROPOSED ODOUR CONTROLS 29

9.9 CUMULATIVE IMPACT ASSESSMENT 30

9.10 SIGNIFICANCE OF IMPACT 31

List of Abbreviations Abbreviation Description

AQAL Air Quality Assessment Level

AQMA Air Quality Management Area

AQSR Air Quality Sensitive Receiver

AQS Air Quality Standard

AC Ambient Concentration

BATC Best Applicable Techniques Conclusion

BAT-AEL Best Applicable Techniques Atmospheric Emission Levels

BREF Best Available Techniques Reference

CERC Cambridge Environmental Research Consultants

DEFRA Department for Environment, Food and Rural Affairs

ESR Ecologically Sensitive Receiver

ELV Emission Limit Values

EfW Energy from Waste

EPUK Environmental Protection United Kingdom

GLC Ground Level Concentrations

HHRA Human Health Risk Assessment

IED Industrial Emissions Directive

IAQM Institute of Air Quality Management

IPPC Integrated Pollution Prevention and Control

Abbreviation Description

LAQM.TG Local Air Quality Management Technical Guidance

OMP Odour Management Plan

OEE Office of Environmental Enforcement

PCDD/F Polychlorinated Dibenzo-p-dioxins and Dibenzofurans

PEC Predicted Environmental Concentration

PC Process Contribution

SEPA Scottish Environmental Protection Agency

SSSI Sites of Special Scientific Interest

SPA Special Protection Areas

TVOC Total Volatile Organic Compounds

TOMPS Toxic Organic Micropollutants Survey

UK HPA United Kingdom Health Protection Agency

US EPA United States Environmental Protection Agency

WI Waste Incineration




Executive Summary

An assessment of air quality impacts arising from the Proposed Energy from Waste (EfW) Development has been

carried out following recommended methodologies for the determination of significance of impact arising from the

emissions associated with the construction and operation of the Proposed EfW Development.

The findings of this assessment are detailed in the following document and summarised below.

Table 9.1: Results of assessment

Receiver Sensitivity

Description

of Impact

Magnitude of

Cumulative Impacts Probability

Significance

of Effects

Significant

- Yes/No?

Human

Health

High Operational

emissions from

EfW stack to

atmosphere at

human

receiver

locations

In terms of annual

mean pollutant

concentrations, there

will be a negligible

change due to the

Process

Contribution.

High Negligible No

Human

Amenity

High Odour

Emissions

from Waste

Acceptance

Hall

Very low potential for

odorous emissions

Highly

unlikely

Negligible No

Ecologically

Sensitive

Receivers

High Operational

emissions from

EfW stack to

atmosphere at

sensitive sites

The predicted

Process

Contributions to

critical loads and

deposition rates on

ecologically sensitive

for relevant

pollutants is

negligible.

High Negligible No

Human

Health and

Ecologically

Sensitive

Receivers

Low Construction

dust emissions

The sensitivity of the

construction site in

relation to human

and ecological

receivers is low and

appropriate

mitigation measures

for dust on a low risk

site is recommended

High Negligible No




9.1 INTRODUCTION

9.1.1 This air quality impact assessment outlines and assesses the potential air quality impacts arising from the

Proposed EfW Development comprising an Energy from Waste (EfW) Plant for the Production of Electricity and

Heat up to 35MW (electric) at Kirkwood Commercial Park, Inverurie, AB51 5NR

9.1.2 A detailed air quality assessment has been undertaken to support the planning application and considers potential

effects on human and ecological receivers due to combustion emissions during operation. In addition, a detailed

construction dust assessment has been undertaken to evaluate the potential effects on public amenity from

emissions of dust during the construction phase of the Proposed EfW Development.

9.1.3 The proposed site is located on Mill Road approximately 0.8km south of Port Elphinstone, and 1.75km south of

Inverurie. The nearest human receiver is located approximately 290m to the east from the stack location on the

Proposed EfW Development site. The nearest ecologically sensitive receiver, the Hill of Barra SSSI, is located

approximately 6.5Km to the north of the Proposed EfW Development. No Special Area of Conservation is located

within 15 Km of the Proposed EfW Development. Other air pollutant sources in proximity to the Proposed EfW

Development include industrial and commercial sites as well as road traffic sources. Industrial and commercial

development is located in close proximity immediately to the west of the site.

9.1.4 The predicted pollutant emissions from the Proposed EfW Development are based on information supplied by

Natural Power to AONA Environmental. This report describes the data used in the modelling, including the

methodology adopted, stack dimensions, stack emission flow rates, emission temperatures, pollutant emission

rates, any assumptions made and the results generated by the air dispersion modelling.

9.1.5 The detailed air quality assessment has outlined the following:

• An evaluation of the existing air quality in the vicinity of the Proposed EfW Development site in order to define

current baseline air quality conditions in the area;

• A quantitative assessment, by means of air dispersion modelling using AERMOD and ADMS, to assess the

potential impact on ambient air quality due to combustion emissions from the Proposed EfW Development

during normal operation;

• A detailed ‘Meteorological Data sensitivity analysis’ and ‘Stack Height Sensitivity Analysis’ has been

undertaken to allow for optimum stack height design.

• A qualitative assessment of the construction dust impacts, risk assessment and mitigation recommendations

during the construction phase of the Proposed EfW Development (See Appendix B);

• A cumulative impact assessment on local air quality due to other existing and proposed sources of air

pollutants in proximity to the Proposed EfW Development site;

• A description of the proposed methods of control of potential odour emissions from the Proposed EfW

Development during normal and abnormal operations; and

• A description of the mitigation measures to minimise potential impact of the Proposed EfW Development on

local air quality.Methodology.

Air Quality Impact Assessment Methodology

9.1.6 In order to determine the potential impact on air quality, and its significance, arising from the operation of the

Proposed EfW Development, the following has been undertaken;

• an assessment of relevant background air pollutant concentrations,

• air dispersion modelling (including both Aermod and ADMS), and

• a comparison of the results obtained against the relevant Ambient Air Quality Standards.

9.1.7 The air dispersion modelling and air quality impact assessment has been carried out in accordance with the

following reference documentation:

• Institute of Air Quality Management (IAQM) – Land-Use Planning & Development Control: Planning For Air

Quality (January 2017)

• Institute of Air Quality Management (IAQM) – A guide to the assessment of air quality impacts on designated

nature conservation sites (June 2019)

• Institute of Air Quality Management (IAQM) – Guidance on the assessment of dust from demolition and

construction (2014)

• Institute of Air Quality Management (IAQM) – Guidance on the assessment of odour for planning (June 2018)

• Local Air Quality Management Technical Guidance LAQM.TG(16) (April 2016).

• Delivering Cleaner Air for Scotland, Development Planning & Development Management Guidance from

Environmental Protection Scotland and the Royal Town Planning Institute Scotland January 2017 & Cleaner

Air for Scotland strategy; Independent Review.

• Environment Agency, Choice of Air Dispersion Models, Policy 522_09 (issued 10/12/09).

• Guidelines for the Preparation of Dispersion Modelling Assessments for Compliance with Regulatory

Requirements – an Update to the 1995 Royal Meteorological Society Guidance UK Atmospheric Dispersion

Modelling Liaison Committee (2004)

• Environmental Protection Agency, Ireland, Office of Environmental Enforcement (OEE), Air Dispersion

Modelling from Industrial Installations Guidance Note (AG4) (2020).

• How to comply with your environmental permit: Additional guidance for: Horizontal Guidance Note H1 - Annex

(f), Environment Agency.




Relevant Legislation

Table 9.2: Relevant Legislation

Industrial

Emissions

Pollution Prevention and Control (Industrial Emissions) Regulations (Scotland)

2012

Industrial

Emissions Directive

Directive 2010/75/EU of the European Parliament and the Council on industrial

emissions is the main EU instrument regulating pollutant emissions from industrial

installations. It recasts seven previously existing directives, including the Integrated

Pollution Prevention and Control (IPPC) Directive and directives concerning large

combustion plants, waste incineration, solvent emissions and waste from the titanium

dioxide industry. The 2012 Regulations transpose Directive 2010/75/EU

Air Quality

Standards

The objectives adopted in Scotland for the purpose of Local Air Quality Management

are set out in the Air Quality (Scotland) Regulations 2000, the Air Quality (Scotland)

Amendment Regulations 2002 and the Air Quality (Scotland) Amendment Regulations

2016. Similar targets are set at EU level, where there are called limit or target values.

These are set out in the European 2008 Ambient Air Quality Directive (2008/50/EC)

and transposed into Scottish legislation by the Air Quality Standards (Scotland)

Regulations 2010.

Emission Limits /

BREF Notes

For EfW plants, the Pollution Prevention and Control (Scotland) Regulations 2012

reference the emission limit values (ELV) stipulated in Annex VI, part 3 of the Industrial

Emissions Directive (IED) (2010/75/EU) form the current legal maximum ELV for

emissions to air from the flue stack of the proposed development.

The Waste Incineration Best Available Techniques reference (BREF) document and

Best Applicable Technique Conclusions (BATC) have recently been updated and

released in December 2019. The ELVs defined in this update are more onerous than

those defined in Annex VI of IED, the Air Quality Assessment will therefore use the

more stringent ELVs from the Waste Incineration BREF as the maximum emissions

from the stack of the proposed development.

Relevant Air Quality Limit Values

9.1.8 Emissions to atmosphere from the Proposed EfW Development will be governed by the Industrial Emissions

Directive (IED), which requires adherence to emission limits for a range of air quality pollutants. The pollutants

addressed in the air quality impact assessment include the following;

• Oxides of Nitrogen (NOx),

• Nitrogen Dioxide (NO2),

• Particulates (PM10 & PM2.5),

• Sulphur Dioxide (SO2),

• Carbon Monoxide (CO),

• Hydrogen chloride (HCl),

• Hydrogen fluoride (HF),

• Cadmium (Cd),

• Mercury (Hg),

• Arsenic (As), Antimony (Sb), Antimony (Sb), Chromium (Cr III), Chromium (Cr VI), Cobalt (Co), Copper (Cu),

Manganese (Mn), Nickel (Ni) & Vanadium (V)

• Dioxins and Furans.

9.1.9 The relevant limit values used in the assessment of the air quality impact of the Proposed EfW Development are

based on the following;

• The Air Quality Standards (Scotland) Regulations 2010 (and amendments)

• Directive 2008/50/EC on ambient air quality and cleaner air for Europe

• Air Quality Guidelines for Europe, the World Health Organisation (WHO)

• Horizontal Guidance Note H1 Environmental Assessment Levels (long and short-term limits).

Table 9.3: Air quality objectives for the production of human health

Pollutant

Air Quality Objective

Concentration Measured as

Benzene (C6H6) 3.25 µg/m3 Running annual mean

1,3-Butadiene 2.25 µg/m3 Running annual mean

Carbon Monoxide (CO) 10.0 mg/m3 Running 8-hour mean

Lead (Pb) 0.25 µg/m3 Annual mean

Nitrogen Dioxide (NO2) 200 µg/m3 not to be exceeded more than 18

times a year

1-hour mean

40 µg/m3 Annual mean

Particles (PM10) 50 µg/m3, not to be exceeded more than 7

times a year

24-hour mean


Particles (PM2.5) 10 µg/m3 Annual mean

Sulphur Dioxide (SO2) 350 µg/m3, not to be exceeded more than 24

times a year

1-hour mean

125 µg/m3, not to be exceeded more than 3

times a year

24-hour mean

266 µg/m3, not to be exceeded more than 35

times a year

15-minute mean

PAH (Polycyclic Aromatic

Hydrocarbons)

0.25 ng/m3 Annual mean

VOCs (Volatile Organic

Compounds as Benzene)


Hydrogen Chloride (HCl) 750 µg/m3 1-hour mean

Hydrogen Fluoride (HF) 16 µg/m3 Annual mean

160 µg/m3 1-hour mean

Ammonia (NH3) 180 µg/m3 Annual mean


Cadmium (Cd) 0.005 µg/m3 Annual mean




Pollutant



1.5 µg/m3 1-hour mean

Mercury (Hg) 0.25 µg/m3 Annual mean


Arsenic (As) 0.003 µg/m3 Annual mean


Antimony (Sb) 5 µg/m3 Annual mean


Chromium (Cr III) 5 µg/m3 Annual mean


Chromium (Cr VI) 0.0002 µg/m3 Annual mean

Cobalt (Co) 0.2 µg/m3 Annual mean


Copper (Cu) 2 µg/m3 Annual mean


Manganese (Mn) 1 µg/m3 Annual mean


Nickel (Ni) 0.02 µg/m3 Annual mean


Vanadium (V) 1 µg/m3 Annual mean


Group 1 Metals - Cadmium (Cd)

Group 2 Metals - Mercury (Hg)

Group 3 Metals - Arsenic (As), Antimony (Sb), Antimony (Sb), Chromium (Cr III), Chromium (Cr VI), Cobalt (Co),

Copper (Cu), Manganese (Mn), Nickel (Ni) & Vanadium (V)

Table 9.4: Air quality objectives for the protection of vegetation and ecosystems.

Pollutant



Oxides of Nitrogen (NOx) 30 µg/m3 Annual mean

75 µg/m3 Daily mean

Sulphur dioxide (SO2) 20 µg/m3

20 µg/m3

Annual mean

Winter Average (Oct - Mar)

Hydrogen Fluoride (HF) 5 µg/m3 Weekly mean


Ammonia (NH3) 3 µg/m3 Annual mean

Pollutant



1 µg/m3 Annual mean for lichens &

bryophytes

9.1.10 According to the UK Health Protection Agency (UK HPA), the regulatory limit for dioxins (and furans) derived from

municipal waste incineration is set at 0.1 ng/m3 of gas emissions. The UK HPA is of the view that since the total

amount of dioxin released by incineration is very small (less than 1%), then for the average person, the proportion

of total dioxin exposure associated with direct inhalation from incineration emissions, is likely to be negligible.

However, in terms of gaseous emissions from incineration, dioxins tend to give rise to the greatest community

concern due to their links to carcinogenic potential and potential adverse effects on reproduction and development.

However, the vast majority of human exposure to dioxins is via the diet. A very small proportion of dioxin exposure

occurs via airborne transmission and incineration of waste accounts for a very small proportion of the total dioxin

emissions to air (UK HPA).

Air Dispersion Modelling Software

9.1.11 The potential ground level concentrations (GLC) of gaseous pollutants at human and ecological receivers in the

vicinity of the Proposed EfW Development has been predicted using both Aermod and ADMS atmospheric

dispersion models, as requested by SEPA.

9.1.12 Atmospheric dispersion and the resultant downwind concentrations of pollutants has been predicted using Aermod

and ADMS atmospheric dispersion models to assess the impacts from airborne releases based on the following

parameters:

• Source emission characteristics including emission rate of pollutant, velocity of discharge, height of discharge

and temperature of the release,

• Prevailing atmospheric conditions including wind speed, direction, cloud cover, precipitation, ambient

temperature and the depth of the mixing layer, and

• Topography and local surface conditions

9.1.13 AERMOD is the US EPA regulatory model used to predict pollutant concentrations from a wide range of sources

that are present at typical industrial facilities. The model accepts hourly meteorological data to define the

conditions for plume rise, transport, diffusion and deposition. It estimates the concentration or deposition value

for each source and receiver combination for each hour of input meteorology and calculates user-selected short-

term averages. Since most air quality standards are stipulated as averages or percentiles, AERMOD allows further

analysis of the results for comparison purposes. Percentile analysis for emissions is calculated for the maximum

averages using the AERMOD-percent post-processing utility. This utility calculates the maximum concentration

of a pollutant from all receivers at a specific percentile, for a specific period. Employing the percentile method

facilitates the omission of unusual short-term meteorological events that may cause elevated pollutant

concentrations and hence a more accurate representation of the likely average pollutant concentrations over an

averaging period.

9.1.14 ADMS-5 has been developed by Cambridge Environmental Research Consultants (CERC) Ltd and is a short-

range dispersion modelling software package that simulates a wide range of buoyant and passive releases to

atmosphere. It is a new generation model utilising boundary layer height and Monin-Obukhov length to describe

the atmospheric boundary layer and a skewed Gaussian concentration distribution to calculate dispersion under

convective conditions.

9.1.15 The main limitations of AERMOD and ADMS are as follows:

• Steady State – does not deal with transient conditions well, limited to a 50km radius.




• Homogeneous meteorological field – not well suited to areas where the meteorological conditions change

quickly.

• Does not model atmospheric chemistry.

9.1.16 It should be noted that none of these limitations will affect the output of the dispersion modelling regarding the

assessment of the proposed development. SEPA widely uses and approves AERMOD and ADMS dispersion

models submitted as part of the Industrial Licencing and Planning Applications. The use of AERMOD and ADMS

dispersion models in the assessment will allow for any potential uncertainty in the results of the model findings to

be dealt with.

Air Dispersion Modelling Inputs

Overview

9.1.17 AERMOD and ADMS dispersion modelling software have been used to model the emissions from the Proposed

EfW Development. In order to model the emissions, data is required in relation to the emission point location,

stack height and diameter, exit velocity, volume flow rate, temperature and pollutant emission rate in grams per

second. Information related to stack diameter, emission velocity, emission temperature and site layout was

provided to AONA Environmental by Natural Power and Agile Energy.

9.1.18 The emission rates used in the modelling of emissions from the Proposed EfW Development were based on a

review of the limits set out in the Industrial Emissions Directive1 and the Best Available Techniques (BAT)

Reference Document for Waste Incineration: Industrial Emissions Directive 2010/75/EU (Integrated Pollution

Prevention and Control)2 (2019). Based on the fact that the recommendations of the BREF are enforceable

through Environmental Permits issued by the Scottish Environmental Protection Agency (SEPA) the specific

emission limits that will be applicable to the Proposed EfW Development are based on the BAT-associated

emission levels (BAT-AELs).

Proposed EfW Development Emission Rates

9.1.19 The emission rates input into the AERMOD and ADMS dispersion models for the Proposed EfW Development are

outlined in Table 9.5.

9.1.20 The Proposed EfW Development contains a number of embedded mitigation factors in the design of the plant.

• The plant design has been screened against the IED BAT Conclusions for Waste Incineration (2019) and had

been determined to comply with all the Best Applicable Techniques categories.

• The furnace type is a fluidised bed which allows for control over combustion temperatures to ensure complete

combustion of organic pollutants and minimises the formation of thermal nitrogen oxides.

• Selective addition of calcium oxide into the fluidised bed, to control Sulphur Dioxide.

• The flue gas treatment includes a bag filter to remove fine particulates.

• Selective injection of ozone is used to further oxidise Nitrogen Oxides and metals to a water-soluble form,

minimising release to air and diverting potential pollutants to the water treatment plant. The injection of ozone

is fully modulated to prevent release of unreacted ozone.

• The flue gas is then fully condensed, the washdown phase allowing further removal of particulates and soluble

pollutants.

9.1.21 In order to ensure a worst-case scenario has been investigated, the point sources have been modelled assuming

continuous operations for 8,760 hours/annum. When calculating the mass emission (in g/s) from a stack, the

volume flow and emission concentration should be at the same temperature, oxygen content and moisture content

1 https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32010L0075&from=EN

(typically both normalised to 273K, dry and the reference oxygen content). When modelling, the actual stack exit

velocity should be input to the model without correction for moisture, oxygen content or temperature (rather than

normalised conditions).

9.1.22 The design of the plant includes embedded mitigation which results in the designed emission levels being

significantly lower than the BAT-AEL. This headroom means that the BAT-AEL limit values represent the worst-

case scenario including start-up, shutdown, and transient other than normal operating conditions.

9.1.23 The stack exit velocity (m/s) is based on the proposed actual rate of release. An emission rate (g/s) which has

been normalised for temperature, moisture and oxygen content has been used in the dispersion model.

Table 9.5: Emission Concentrations (mg/m3) and Mass Emission Rates (g/s) used in the air dispersion model.

Pollutant

Stack

Diameter

(m)

Stack

Exit

Velocity

(m/s)

Volume

Flow

(m3/s)

Temp

(Kelvin)

Normalised

Volume

Flow

(Nm3/s)

BAT AEL

Emission

Conc.

(mg/Nm3)

Normalised

Mass

Emission

Rate (g/s)

NOx (NO and NO2 expressed as

NO2)

1.75 11.1 26.7 330 33 120 3.95977

Carbon monoxide (CO) 1.75 11.1 26.7 330 33 50 1.64991

Dust / PM 1.75 11.1 26.7 330 33 5 0.16499

Sulphur dioxide SO2 1.75 11.1 26.7 330 33 30 0.98994

TVOC 1.75 11.1 26.7 330 33 10 0.32998

Hydrogen chloride (HCl) 1.75 11.1 26.7 330 33 6 0.19799

Hydrogen fluoride (HF) 1.75 11.1 26.7 330 33 1 0.033

Ammonia (NH3) 1.75 11.1 26.7 330 33 10 0.32998

Mercury (Hg) 1.75 11.1 26.7 330 33 0.02 0.00066

Cd & Tl 1.75 11.1 26.7 330 33 0.02 0.00066

Sb&As&Pb&Cr&Co&Cu&Mn&Ni&V 1.75 11.1 26.7 330 33 0.3 0.0099

PCDD/F 1.75 11.1 26.7 330 33 6.00E-08 2E-09

PCDD/F & dioxin-like PCBs 1.75 11.1 26.7 330 33 8.00E-08 2.6E-09

1. The point source modelled at concentration limit assuming continuous operations for 8760 hours/annum.

2. When modelling, the actual stack exit velocity should be input to the model without correction for moisture, oxygen content or

temperature (rather than normalised conditions).

3. When calculating the mass emission (in g/s) from a stack, the volume flow and emission concentration should be at the same

temperature, oxygen content and moisture content (normalised to 273K, dry & reference oxygen)

4. Model Input Data highlighted in Green.

5. Worst-case emission concentrations based relevant BREF BAT AELs.

Building Downwash Effects

9.1.24 Buildings can affect the local mechanical turbulence around the point of release. Air moving over buildings

increases in velocity and can cause downwash downwind of the source. Releases can be partly or wholly

entrained into the building slip-stream leading to occasional elevated local ground level concentrations when wind

direction increases the influence of nearby buildings on dispersion of the plume. Due to this fact, stack heights as

well as building dimensions, shape and orientations have been incorporated into the model. AERMOD and ADMS

include algorithms to model the effects of building downwash on emissions from nearby or adjacent point sources.

2 https://ec.europa.eu/jrc/en/publication/eur-scientific-and-technical-research-reports/best-available-techniques-bat-reference-

document-waste-incineration-industrial-emissions

https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32010L0075&from=EN

https://ec.europa.eu/jrc/en/publication/eur-scientific-and-technical-research-reports/best-available-techniques-bat-reference-document-waste-incineration-industrial-emissions

https://ec.europa.eu/jrc/en/publication/eur-scientific-and-technical-research-reports/best-available-techniques-bat-reference-document-waste-incineration-industrial-emissions




The proposed building dimensions i.e. plans and elevations of the proposed site layout have been provided to

AONA Environmental. Figure 9.1 below indicates a 3D model of the Proposed EfW Development buildings and

stack as taken from the Google Earth export from the AERMOD dispersion model.

Figure 9.1: 3D model of the Proposed EfW Development buildings and stack as taken from the Google Earth export from the AERMOD dispersion model.

Source Google Earth

Receiver Locations

9.1.25 The AERMOD and ADMS models calculate pollutant concentrations at receiver points in the vicinity of the

modelled emission point. Pollutant concentrations were predicted at a selection of the nearest human properties

in proximity to the Proposed EfW Development site as outlined in Table 9.6. These 20 sensitive human health

receiver locations are representative of sensitive human health receivers located to the north, south, east and west

of the Proposed EfW Development site. A detailed air quality impact assessment at each of these locations allows

for a thorough assessment at all sensitive human health receiver locations in proximity to the Proposed EfW

Development site. Pollutant concentrations at locations further from the Proposed EfW Development site can be

taken to be lower than at any of these 20 sensitive human health receiver locations.




Table 9.6: Location of air quality sensitive receivers (AQSR) in the area of the proposed site.

Description Grid Reference Address

AQSR 1 378491 819165 Uryside, Port Elphinstone, Aberdeenshire, Scotland, AB51 0LS



AQSR 4 378605 819071 Kinkell Churchyard, Mill Road, Uryside, Port Elphinstone,

Aberdeenshire, Scotland, AB51 5NR


AQSR 6 378818 820129 B993, Pittrichie, Whiterashes, Aberdeenshire, Scotland, AB51 0LU

AQSR 7 378067 819803 Crichie Circle, Uryside, Port Elphinstone, Aberdeenshire, Scotland,

AB51 3XG


AB51 3XG


AB51 3XG


AB51 3XG

AQSR 11 377981 819465 Standing Stone, Mill Lane, Uryside, Port Elphinstone,

Aberdeenshire, Scotland, AB51 5UA

AQSR 12 377858 819485 Mill Lane, Uryside, Port Elphinstone, Aberdeenshire, Scotland,

AB51 5UA

AQSR 13 377843 819530 Mill Lane, Uryside, Port Elphinstone, Aberdeenshire, Scotland,

AB51 5UA

AQSR 14 377748 819542 Mill Road, Uryside, Port Elphinstone, Aberdeenshire, Scotland,

AB51 5UD

AQSR 15 377871 819318 Mill Road, Uryside, Port Elphinstone, Aberdeenshire, Scotland,

AB51 5NQ

AQSR 16 377575 818596 Thainstone Court, Uryside, Port Elphinstone, Aberdeenshire,

Scotland, AB51 5YA

AQSR 17 377345 818774 Thainstone House, Thainstone, Uryside, Port Elphinstone,

Aberdeenshire, Scotland, AB51 5NT

AQSR 18 377178 818666 Thainstone House, Thainstone, Uryside, Port Elphinstone,

Aberdeenshire, Scotland, AB51 5NT

AQSR 19 378099 818289 Inverurie - Kintore Shared Use Path, Uryside, Port Elphinstone,

Aberdeenshire, Scotland, AB51 0YR

AQSR 20 378141 818293 Inverurie - Kintore Shared Use Path, Uryside, Port Elphinstone,

Aberdeenshire, Scotland, AB51 0YR

Figure 9.2: Location of air quality sensitive receivers (AQSR) in the area of the proposed site.

Source Google Earth

9.1.26 Ground level pollutant concentrations were also predicted at every node on Cartesian grids, with centre

coordinates of 378200, 819230, as follows;

• Cartesian Grid 1 – 500m x 500m @ 25m spacing,

• Cartesian Grid 2 – 1,000m x 1,000m @ 50m spacing,



• Cartesian Grid 5 – 8,000m x 8,000m @ 200m spacing.

9.1.27 Ecologically designated sites within 15 km of the Proposed EfW Development including RAMSAR, Special

Protection Areas (SPA) & Sites of Special Scientific Interest (SSSI) have been included in the air dispersion model.

The locations of the sensitive ecological receivers considered in the study are shown in Table 9.7.




Table 9.7: Ecologically sensitive receiver sites (ESR) within 20 km of the development.

Site No. Name Distance (km) Designation Easting Northing

1 Hill of Barra 6.685 SSSI 380262 825481

2 Pitcaple and Legatsden

Quarries

8.327 SSSI 373783 826161

3 Paradise Wood 10.302 SSSI 367941 818434

4 Pittodrie 10.33 SSSI 369371 824445

5 Loch of Skene 11.009 SSSI 378242 808107

6 Loch of Skene 11.009 SPA 378242 808107

7 Tilliefoure Wood 11.159 SSSI 367062 819060

8 Red Moss, Oldtown 13.258 SSSI 382827 831547

9 Corby, Lily and Bishops

Lochs

13.656 SSSI 390983 814257

10 Wartle Moss 13.82 SSSI 372717 831793

Figure 9.3: Designated sites within 15 Km of the proposed EfW Plant.

Time Averaging and Percentiles

9.1.28 The time averaging and percentiles have been calculated in terms of the pollutant concentration limit values criteria

detailed in the air quality objectives. For example, the time averaging and percentiles have been calculated in

terms of the concentration limit values criteria detailed in the relevant Air Quality Standard limits outlined in Table

1. For example, NO2 has been calculated as a 99.79th percentile of 1-hour mean concentrations and PM10 has

been calculated as a 98.08th percentile of 24-hour mean concentrations.

Terrain Data

9.1.29 Terrain Data for the area surrounding the Proposed EfW Development has been incorporated in the AERMOD

and ADMS dispersion models. 50m x 50m terrain data has been sourced from Ordnance Survey. Using a

convertor the Digital Terrain Model data has been converted to Digital Elevation Model (DEM) format to allow for

use of the AERMOD terrain pre-processor (AERMAP).

Surface Roughness & Land Use Characteristics

9.1.30 The local area around the Proposed EfW Development site is a mix of suburban and rural lands with a combination

of open fields and some woodland areas surrounding the site.

9.1.31 Surface roughness is a measure of the aerodynamic roughness of the surface and is related to the height of the

roughness element. The input requirements for the AERMET Meteorological Pre-processor include surface

characteristics (such as surface roughness, Bowen ratio, and albedo) and hourly meteorological data (wind speed,

wind direction, cloud cover, and temperature). In relation to AERMOD, the most pertinent features for calculating

the relevant surface parameters are that the surface characteristics should be those of the meteorological site

rather than the installation. The surface roughness should use a default 1Km radius upwind of the meteorological

tower and should be based on an inverse-distance weighted geometric mean. The land use around the site should

be sub-divided by sectors with a minimum sector size of 30º and the Bowen ratio and albedo should be based on

a 10km grid. The ‘dispersion coefficient’ has been set for rural surroundings in the AERMOD model for the area

in the vicinity of the Proposed EfW Development site. The ‘land use type’ for the surrounding area has been

selected to be ‘grassland’. The following Albedo, Bowen ratio and Surface Roughness Lengths (m) have been

input to the AERMOD model.

Table 9.8: Albedo, Bowen ratio and Surface Roughness Lengths (m)

Winter Spring Summer Autumn Annual Average

Albedo Note 1 0.6 0.18 0.18 0.2 0.29

Bowen Ratio Note 2 1.5 0.4 0.8 1 0.925

Surface Roughness Length (m) Note 3 0.001 0.05 0.1 0.01 0.04

9.1.32 A roughness length (z0) of 0.5m was used within the ADMS model to describe the dispersion extents. This value

of z0 is considered appropriate for the morphology of the area and is suggested within ADMS-5 as being suitable

for 'parkland, open suburbia'. A z0 of 0.3 m was used within the ADMS model to describe the meteorological site.

This value of z0 is considered appropriate for the morphology of the area and is suggested within ADMS-5 as being

suitable for 'agricultural areas (max)'. The Monin-Obukhov length provides a measure of the stability of the

atmosphere. A minimum Monin-Obukhov length of 10m was used within the model to describe the dispersion

extents and meteorological site. This value is considered appropriate for the nature of the area and is suggested

within ADMS-5 as being suitable for a 'small towns <50,000'.

NOx to NO2 Chemistry

9.1.33 In the atmosphere, nitric oxide emissions from combustion sources are oxidised to nitrogen dioxide. The rate of

oxidation is dependent on the relative concentrations of nitric oxide and ozone in the ambient air. Emissions of




nitrogen oxides from industrial point sources are dominated by nitric oxide (NO), with emissions from combustion

sources typically in the ratio of 9:1 for nitric oxide to nitrogen dioxide. Therefore, as it is nitrogen dioxide that has

a specific limit value for the protection of human health, in accordance with Environment Agency technical

guidance, it is assumed that 70% of nitric oxide emitted from the stack is oxidised to nitrogen dioxide in the long

term and 35% of the emitted nitric oxide is oxidised to nitrogen dioxide in the local vicinity of the site in the short-

term. ‘Long term’ and ‘short-term’ refer to the annual mean and 1-hour mean concentrations of nitrogen dioxide.

Proposed EfW Development Stack

9.1.34 The location of the proposed stack and adjacent buildings has been extracted from the CAD drawings provided to

AONA Environmental and scaled accordingly within the air dispersion models. The Proposed EfW Development

stack will be located at UK Grid Reference 378199, 819228. The highest proposed building on the site is 46.5m

with small adjoining sections of the main building reaching a height of 50.5m. A range of stack heights from 55m

to 90m have been assessed using the AERMOD and ADMS dispersion modelling software to assess the potential

impact of the Proposed EfW Development emissions. The purpose of the stack height assessment is to determine

an appropriate stack height for the emission point in order to ensure effective dispersion of combustion gases.

The selection of an appropriate stack height is open to interpretation of dispersion model output data and decided

upon based on professional judgement and other specific project criteria such as visual impact.

9.1.35 For direct comparison of the Aermod and ADMS models, NO2 emissions have been assessed in accordance with

Environment Agency technical guidance, i.e. 70% of nitric oxide emitted from the stack is oxidised to nitrogen

dioxide in the long term and 35% of the emitted nitric oxide is oxidised to nitrogen dioxide in the local vicinity of the

site in the short-term.

9.1.36 The optimum stack height, from the perspective of applying Best Available Technique (BAT), occurs at the point

where the incremental decrease in ground level concentration becomes disproportionate to the incremental

increase in stack height. Based on the data presented in Table 6 and Charts 1 & 2, the ‘knee-point’ of the ground

level concentration versus stack height occurs at 70m. Based on model output data, professional judgement,

specific project criteria such as visual impact and discussion with Natural Power and Agile Energy, it is determined

that a 70m stack (at least) is recommended for the Proposed EfW Development. This is 23.5m above the main

building height on the site.

Table 9.9: Stack Height Sensitivity Analysis - Maximum Ground Level Concentrations.

Stack

Height

AERMOD

99.79th %ile

of 1-Hour

NO2 GLC

(µg/m3)

%age

of

Limit

Value

AERMOD

Annual

Mean NO2

GLC

(µg/m3)

%age

of

Limit

Value

ADMS

99.79th %ile

of 1-Hour

NO2 conc. at

Receivers

(µg/m3)

%age

of

Limit

Value

ADMS

Annual

Mean NO2

conc. at

Receivers

(µg/m3)

%age

of

Limit

Value

55 28.85 14.4% 1.84 0.9%

60 24.51 12.3% 1.15 0.6%

65 23.14 11.6% 0.78 0.4% 7.47 3.7% 1.14 0.6%

70 22.36 11.2% 0.55 0.3% 6.45 3.2% 0.86 0.4%

75 20.49 10.2% 0.42 0.2% 5.50 2.7% 0.67 0.3%

80 20.20 10.1% 0.41 0.2% 4.80 2.4% 0.55 0.3%

85 18.46 9.2% 0.35 0.2% 4.29 2.1% 0.44 0.2%

90 15.15 7.6% 0.30 0.2%

Limit

Value

200 40 200 40

Chart 1: AERMOD Model – Stack Height Sensitivity Analysis




Chart 1: ADMS Model – Stack Height Sensitivity Analysis

9.1.37 The predicted annual mean and 99.79th percentile of 1 hour ground level NO2 concentrations will decrease

significantly with increasing stack heights from 55m to 90m and the potential for building downwash effects to

occur decrease.

Meteorological Data

9.1.38 Hourly sequential meteorological data from Aberdeen (Dyce) Airport for the years 2015 to 2019 was used in the

air dispersion modelling. The Aberdeen (Dyce) Airport is the closet synoptic station to the Proposed EfW

Development that offers data in a suitable format and it is representative of meteorological conditions in the

immediate area of the Proposed EfW Development. The meteorological station located at Aberdeen (Dyce) Airport

is located 11.5 Km to the south-east of the Proposed EfW Development.

Chart 3: Aberdeen (Dyce) Airport meteorological data for the years 2015 to 2019.

2015 2016

2017 2018

2019




9.2 ASSESSMENT OF SIGNIFICANCE OF POTENTIAL ENVIRONMENTAL

EFFECTS

9.2.1 In terms of the ‘Significance of Potential Environmental Effects’ the magnitude (scale of change) has been

determined by considering the impacts of the Proposed EfW Development on air quality with reference to the

baseline conditions and environmental assessment criteria.

Describing the Impact:

9.2.2 The rationale for describing the impact of the Proposed EfW Development is derived from the Environmental

Protection UK (EPUK) and Institute of Air Quality Management (IAQM) guidance (EPUK & IAQM) “Land-Use

Planning & Development Control: Planning for Air Quality (January 2017).

9.2.3 There is a two-stage process to be followed in the assessment of air quality impacts

• a qualitative or quantitative description of the impacts on local air quality arising from the development; and

• a judgement on the overall significance of the effects of any impacts

9.2.4 The suggested framework for describing the impacts is set out in Table 6.3 of the EPUK & IAQM guidance

document and is shown in Table 7. The term Air Quality Assessment Level (AQAL) has been adopted as it covers

all pollutants, i.e. those with and without formal standards. AQAL is used to include air quality objectives or limit

values where these exist. The Environment Agency uses a threshold criterion of 10% of the short term AQAL as

a screening criterion for the maximum short-term impact. The EPUK & IAQM guidance adopts this as a basis for

defining an impact that is sufficiently small in magnitude to be regarded as having an insignificant effect.

Table 9.10: Impact descriptors for individual receivers

Long term average

Concentration at Receiver in

assessment year

% Change in concentration relative to Air Quality Assessment Level

(AQAL)

1 2-5 6-10 >10

75% or less of AQAL Negligible Negligible Slight Moderate

76-94% of AQAL Negligible Slight Moderate Moderate

95-102% of AQAL Slight Moderate Moderate Moderate

103-109% f AQAL Moderate Moderate Substantial Substantial

110% or more of AQAL Moderate Substantial Substantial Substantial

Explanation

1. AQAL = Air Quality Assessment Level, which may be an air quality objective, EU limit or target value, or an

Environment Agency ‘Environmental Assessment Level (EAL)’.

2. The Table is intended to be used by rounding the change in percentage pollutant concentration to whole

numbers, which then makes it clearer which cell the impact falls within. The user is encouraged to treat the

numbers with recognition of their likely accuracy and not assume a false level of precision. Changes of 0%,

i.e. less than 0.5% will be described as Negligible.

3. The Table is only designed to be used with annual mean concentrations.

4. Descriptors for individual Receivers only; the overall significance is determined using professional

judgement (see Chapter 7). For example, a ‘moderate’ adverse impact at one Receiver may not mean that the

overall impact has a significant effect. Other factors need to be considered.

Long term average

Concentration at Receiver in

assessment year

% Change in concentration relative to Air Quality Assessment Level

(AQAL)

1 2-5 6-10 >10

5. When defining the concentration as a percentage of the AQAL, use the ‘without scheme’ concentration

where there is a decrease in pollutant concentration and the ‘with scheme;’ concentration for an increase.

6. The total concentration categories reflect the degree of potential harm by reference to the AQAL value. At

exposure less than 75% of this value, i.e. well below, the degree of harm is likely to be small. As the exposure

approaches and exceeds the AQAL, the degree of harm increases. This change naturally becomes more

important when the result is an exposure that is approximately equal to, or greater than the AQAL.

7. It is unwise to ascribe too much accuracy to incremental changes or background concentrations, and this is

especially important when total concentrations are close to the AQAL. For a given year in the future, it is

impossible to define the new total concentration without recognising the inherent uncertainty, which is why

there is a category that has a range around the AQAL, rather than being exactly equal to it.

Assessing Significance

9.2.5 The rationale for the assessment of significance is derived from the EPUK & IAQM Guidance (paragraphs 7.1-

7.12 referring to Table 6.3) and relates to Table 9.10.

9.2.6 Impacts on air quality, whether adverse or beneficial, will have an effect on human health that can be judged as

‘significant’ or ‘not significant’. An ‘impact’ is the change in the concentration of an air pollutant, as experienced by

a Receiver. This may have an ‘effect’ on the health of a human Receiver, depending on the severity of the impact

and other factors that may need to be taken into account. The impact descriptors set out in Table 7 are not, of

themselves, a clear and unambiguous guide to reaching a conclusion on significance. These impact descriptors

are intended for application at a series of individual Receivers. Whilst it may be that there are ‘slight’, ‘moderate’

or ‘substantial’ impacts at one or more Receivers, the overall effect may not necessarily be judged as being

significant in some circumstances.

Any judgement on the overall significance of effect of a development will need to take into account such factors

as:

• the existing and future air quality in the absence of the development;

• the extent of current and future population exposure to the impacts; and

• the influence and validity of any assumptions adopted when undertaking the prediction of impacts.

• Other factors may be relevant in individual cases.




9.3 EXISTING ENVIRONMENT

Air Quality Management Areas

9.3.1 The Environment Act 1995 and the Air Quality Strategy for England Scotland Wales and Northern Ireland 2007

establish the principle of Local Air Quality Management, which places an obligation upon the Local Authority to

review and assess air quality in their area and determine whether Air Quality Objectives are likely to be achieved.

If there is evidence that Objectives are not being, or might not be, achieved the Act places an obligation upon the

Local Authority to declare Local Air Quality Management Areas and develop Action Plans to reduce pollutant levels

to below the objectives. It is important therefore the Local Authority ensure that new development does not result

in a failure to meet the Air Quality Objectives. The Proposed EfW Development site does not lie within or near to

an AQMA. Aberdeenshire Council has not declared any AQMA.

Baseline Air Quality

9.3.2 Baseline air quality information has been obtained from the following sources

• 2019 Air Quality Annual Progress Report for Aberdeenshire Council as part of its obligation under Part IV of

the Environment Act 1995,

• data produced by Air Quality in Scotland, and

• data produced by DEFRA.

9.3.3 A range of information sources have been considered to enable baseline air quality in the local area to be

characterised. Details of any automatic monitoring station and non-automatic diffusion tube monitoring sites in

proximity to the Proposed EfW Development site have been referenced and relevant monitoring data for LAQM

pollutants at the nearest monitoring stations to the Proposed EfW Development is outlined below.

Nitrogen Dioxide (NO2)

9.3.4 Aberdeenshire Council does not operate any automatic analysers or monitors in respect of NOx and / or NO2.

Aberdeenshire Council operates 14 non-automatic monitoring locations across its jurisdictional area. The Annual

Mean NO2 concentrations in Table 8 are referenced from the Aberdeenshire Council APR for 2019 for the non-

automatic diffusion tube monitoring locations located within Inverurie. The nearest to the Proposed EfW

Development site is Inverurie MC and Inverurie 21HS, both of which are roadside monitoring locations situated

approximately 2Km north-north-west of the Proposed EfW Development site.

Table 9.11: Aberdeenshire Council Monitoring Results –Non-Automatic Monitoring Locations in proximity to site location– Site Location Grid Reference, 378219, 819059

Site I.D. Grid Coordinate Site Type

Distance from

Proposed EfW

Dev. (km)

Annual Mean NO2

Concentrations (µg/m3)

2016 2017 2018

Inverurie MC 377624, 821295 Roadside ~2 31.0 24.3 24

Inverurie 21HS 377602, 821323 Roadside ~2 28.2 21.6 23.1

Inverurie 1 (West

High Street)

376622, 821476 Roadside ~2.6 31.5 27.7 26.4

Inverurie 2 (Gordon

House)

377624, 821295 Backgroun

d

~2.4 10.5 8.8 10.3

Limit Value 40

9.3.5 The annual mean NO2 concentrations at the roadside monitoring locations in Inverurie are approximately 75% of

the relevant air quality objective limit value and the annual mean NO2 concentration at the background monitoring

location in Inverurie is approximately 25% of the relevant air quality objective limit value. This monitoring data

indicates that the air quality in proximity to the development site is in compliance with The Air Quality Standards

Regulations 2010.

9.3.6 NO2 concentrations are routinely measured at sites across the UK as part of the Acid Gas and Aerosol Network .

The closest monitoring site at Glensaugh is situated approximately 41km to the south-west of the to the Proposed

EfW Development site. This is a rural background monitoring location (upland moorland site). The annual mean

NO2 concentration monitored at this location in 2019 was 2.53 μg/m3.

Particulate Matter (PM10 and PM2.5)

9.3.7 Aberdeenshire Council does not carry out any monitoring in respect of PM10 or PM2.5 within the council area.

The air quality objective for PM10 particulates is unlikely to be exceeded within Aberdeenshire Council’s area

based on the fact that Aberdeenshire Council currently does not have any AQMAs.

9.3.8 Simple Calculation of Atmospheric Impact Limits from Agricultural Sources (SCAIL-Agriculture) is a screening tool

for assessing the impact from pig and poultry farms on human health and on semi-natural areas like SSSIs and

SACs. SCAIL Agriculture outlines the following background PM10 concentrations at the designated ecological

sites within 15 Km of the Proposed EfW Development site.

Table 9.12: SCAIL-Agriculture background PM10 concentrations at the designated ecological sites within 15 Km of the Proposed EfW Development site.

Receiver Name PM10 Background (µg/m3)

1 Hill Of Barra 11.01

2 Pitcaple and Legatsden Quarries 12.39

3 Pittodrie 8.87

4 Paradise Wood 9.1

5 Loch Of Skene SPA 11

6 Loch of Skene SSSI 11

7 Tilliefoure Wood 8.35

8 Red Moss, Oldtown 10.8

9 Wartle Moss 12.47

10 Corby, Lily and Bishops Lochs 14.21

9.3.9 On the basis of the above, a worst-case background PM10 concentration of 14 µg/m3 has been assumed in

proximity to the Proposed EfW Development site.




Sulphur Dioxide, Carbon Monoxide, Lead and 1,3-Butadiene

9.3.10 Aberdeenshire Council does not carry out any monitoring in respect of Sulphur Dioxide, Carbon Monoxide, Lead

and 1,3-Butadiene and has no current plans to do so. SO2 concentrations are routinely measured at Glensaugh.

The annual mean SO2 concentration monitored at this rural background monitoring location in 2019 was 0.148

μg/m3.

Ammonia

9.3.11 Ammonia (NH3) is measured at sites across the UK under the National Ammonia Monitoring Network. The nearest

monitoring location to the Proposed EfW Development site is situated at Oldmeldrum ~9.5km to the north-east.

The annual mean NH3 concentration monitored at this location in 2019 was 1.19 μg/m3.

Metals

9.3.12 Metal concentrations are measured in the UK by Defra under the Rural Heavy Metals Network and the Urban

Heavy Metals Network. The nearest monitoring location to the Development Site is situated at Auchencorth Moss,

approximately 165 km to the south-west, which is a rural monitoring location. Table 10 summarises the 2018

monitored data of individual metals at Auchencorth Moss.

Table 9.13: Monitored metal concentrations at Auchencorth Moss

Metal Annual Mean Concentration (ng/m3)

Arsenic 0.2

Cadmium 0.026

Chromium Note 1 1.528

Cobalt 0.073

Copper 0.884

Lead 1.031

Manganese 1.137

Nickel 0.247

Vanadium 0.320

Note 1: The ratio of total Cr to Cr(VI) in ambient air depends on local emission sources. A review of

information by the UK’s Expert Panel on Air Quality Standards (EPAQS) indicates that Cr(VI) constitutes

between 3% and 33% of airborne Chromium , while the US Department of Health suggests the ratio is

between 10% and 20%. EPAQS report that ambient Cr(VI) concentrations may typically constitute 3-8% of

total Cr. Therefore, as a worst case Cr VI taken to be 20% of Cr III value.

PCDD/Fs

9.3.13 In the UK, Defra’s Toxic Organic Micropollutants Survey (TOMPS) is the principal source of data on the measured

concentrations of PCDD/Fs, dioxin-like PCBs and PAHs in ambient air at six locations (two urban background

sites, and four rural background sites). The closest monitoring station to the Proposed EfW Development site is

the rural background station at Auchencorth Moss. The most recent (2010) annual mean PCDD/F data measured

at the Auchencorth Moss monitoring location is 15.8 fgTEQ/m3.

9.3.14 The nearest urban background monitoring location is in Manchester. The annual mean dioxin PCDD/F data

measured at the Manchester monitoring location for 2010 is 48.7 fgTEQ/m3. In line with decreasing PCDD/F

emissions since 1990, data from the TOMPS survey has shown corresponding decreases in ambient

concentrations of PCDD/Fs in urban locations since the early 1990s.

Polycyclic Aromatic Hydrocarbons (PAH)

9.3.15 PAHs are measured at sites across the UK. The nearest urban background monitoring station to the Proposed

EfW Development site which has recent data (post 2006) is Glasgow Townhead. The 2018 monitored PAH

concentration (as B(a)P) was 0.092 ng/m3.

Background Maps

9.3.16 Background maps have been provided to assist Scottish local authorities in support of the Review and Assessment

of local air quality. Mapped background concentrations for use in LAQM Review and Assessments are available

on the Scottish Air Quality Website. These maps differ from the Defra UK model maps and are created from a

Scotland-specific model using Scottish monitoring data and Scottish meteorological data. Scotland specific maps

are not currently available for PM2.5. The Scottish Government advise that for this pollutant, Defra UK wide

background maps are used in the review and assessment of local air quality.

Table 9.14: Published background concentrations (µg/m3) in proximity to the Proposed EfW Development site

Year

Grid Coordinate Annual Mean Concentration (µg/m3)

Easting Northing NO2 NOx PM10 PM2.5

2020 334500 374500 3.699 5.192 11.562 5.436

Background Concentrations used in the Air Quality Impact Assessment

9.3.17 As outlined in LAQM TG(16), the following approach to adding industrial installation contributions to the

background NO2 and PM10 concentrations should be adopted.

NO2

9.3.18 Where this approach suggests that the predicted increase in the 99.79th percentile above the background is more

than 75% of the available headroom (the difference between the objective and background), then a more detailed

approach will be required.

The 99.79th percentile of total NO2 is equal to the minimum of either equation a or b:

a) 99.79th percentile hourly background total oxidant + 0.05 × (99.79th percentile process contribution NOx); or

b) the maximum of either:

b1) 99.79th percentile process contribution of NOx + (2 × annual mean background NO2); or

b2) 99.79th percentile hourly background NO2 + (2 × annual mean process contribution of NOx).

Note: In equation a, the total oxidant is the sum of O3 and NO2 (as NO2 equivalents) and should be based on

summing the hour by hour concentrations from a suitable background monitoring site in order to derive the 99.79th

percentile.

PM10

9.3.19 Where this approach suggests that the predicted increase in the 98.08th percentile above the background is more

than 50% of the available headroom (the difference between the objective and background), then a more detailed

approach will be required.

The 98.08th percentile total 24-hour mean is equal to the maximum of either equation a or b;




a) 98.08th percentile 24-hour mean background + annual mean process contribution; or

b) 98.08th percentile 24-hour mean process contribution + annual mean background.

Note: for the 98.08th percentile for 24-hour mean, the method does not incorporate twice the annual mean

contribution of the process or background.

9.3.20 A representative baseline air quality level has been identified for the area in proximity to the nearest human

receivers to the Proposed EfW Development to provide a realistic worst-case estimate of baseline air quality levels

in the study area, based on the representative available background data, as set out in Table 9.15.

Table 9.15: Baseline data summary of background air quality concentrations in the study area.

Pollutant

Averaging

time

AQ

Objective

Baseline conc.

used in

Assessment

(μg/m3) Notes

NO2 99.79th %ile of

hourly means

200 20 μg/m3 2x Annual Mean. Background annual mean

NO2 measured in Inverurie = 10 μg/m3.

Realistic worst-case background

concentration.

Annual mean 40 10 μg/m3 Annual mean NO2 measured in Inverurie at

Background Location = 10.5 μg/m3. Air

Quality in Scotland Bkg. Maps NO2 Bkg.

Conc. at 378500, 819500 = 3.7 μg/m3.

NOx Annual mean 30 15 μg/m3 Air Quality in Scotland Bkg. Maps NO2 Bkg.

Conc. at 378500, 819500 = 5.2 μg/m3.

Realistic worst-case background

concentration.

PM10 98.08th %ile of

24 hour means

50 14 μg/m3 1 x Annual Mean. Realistic worst-case

background concentration.

Annual mean 18 14 μg/m3 Air Quality in Scotland Bkg. Maps PM10

Conc. at 378500, 819500 = 11.56 μg/m3.

SCAIL Agriculture outlines a Bkg. PM10

Conc. of 14 μg/m3. Realistic worst-case


PM2.5 Annual mean 10 8 μg/m3 Air Quality in Scotland advises that for

PM2.5, Defra UK background maps are

used. PM2.5 Bkg. Conc. at 378500,

819500 = 5.4 μg/m3. Realistic worst-case


CO Running 8-

hour mean

10,000 500 μg/m3 Realistic worst-case background

concentration.

Pollutant

Averaging

time

AQ

Objective

Baseline conc.

used in

Assessment

(μg/m3) Notes

Benzene Annual mean 5 0.8 μg/m3 Realistic worst-case background

concentration.

SO2 99.7th %ile of

hourly means

350 25 μg/m3 Realistic worst-case background

concentration.

99.2th %ile of

24 hour means

125 10 μg/m3 Realistic worst-case background

concentration.

Annual mean 20 5 μg/m3 Realistic worst-case background

concentration.

9.4 AIR DISPERSION MODELLING RESULTS

Predicted Impacts on Human Receivers

9.4.1 The outputs from the air quality pollutant dispersion modelling study indicate worst-case predicted ground level

concentrations in the vicinity of the Proposed EfW Development.

9.4.2 The results of the air dispersion modelling study when added to the relevant background air pollutant

concentrations as outlined in LAQM TG(16), have been compared against the relevant Air Quality limit values.

The approach to the assessment of the potential impact on ambient air quality of the emissions from the stack of

the Proposed EfW Development has involved the following:

• Quantification of the local Ambient Concentration (AC) from consideration of DEFRA estimated background

air pollutant concentrations in the vicinity of the Proposed EfW Development (Annual Mean Concentrations),

• Quantitative assessment of the impact of operational emissions on local air quality and a quantification of the

Process Contributions (PC).

• Assessment of the resultant Predicted Environmental Concentrations (PEC) through addition of the Ambient

Concentration (AC) and the Process Contributions (PC) emissions. In order to obtain the Predicted

Environmental Concentrations (PEC), a realistic worst-case estimate of background concentrations as outlined

in Table 9.15 were added directly to the predicted process concentrations.

The ground level concentrations presented in Tables 9.16 – 9.19 are based on the BAT-AEL emission

concentration limits.

No background concentrations have been input onto the air dispersion models. The results of the dispersion

modelling study indicate the predicted process contribution emissions from the Proposed EfW Development

presented as concentration isopleths (See Appendix A, Figures A1 – A13). The concentration isopleths have been

presented on Google Earth background mapping.

https://uk-air.defra.gov.uk/data/laqm-background-home




Table 9.16: Baseline data summary of background air quality concentrations in the study area.

Pollutant Period Average Ambient

Conc.

(AC)

(μg/m3)

Predicted

Process

Contribution

(PC)

(μg/m3)

Predicted

Env.

Conc.

(PEC)

(μg/m3)

AQS /

EAL

Value

µg/m³

PC

%age

of limit

value

PEC

%age

of limit

value


Conc.

(AC)

(μg/m3)

Predicted

Process

Contribution

(PC)

(μg/m3)

Predicted

Env.

Conc.

(PEC)

(μg/m3)

AQS /

EAL

Value

µg/m³

PC

%age

of limit

value

PEC

%age

of limit

value

16

0.6%

Annual Mean

Conc.

0.007 0.0

Hydrogen

Chloride (HCl)

1 Hour Conc. 5.359 5.4

1.3%

3.5%

0.7%0.7%

0.6%

0.0%0.0%

125 1.7%

750

5

0.033

17.3%

10 0.3% 80.3%

9.7%

200

Annual Mean

Conc.

10.0 0.550 10.6

Sulphur Dioxide

(SO2)99.7th %ile of Max.

1 Hour Conc.

25.0 12.290 37.3

20.0 22.300 42.3

Hydrogen

Flouride (HF)

1 Hour Conc.

14.0 0.033 14.0

99.2th %ile of Max.

24 Hour Conc.

10.0

0.4%2500

0.893 0.9 160

11.2% 21.2%

5.1%

0.4%

Volatile Organic

Compounds

PM10

40 1.4%

14.2

Nitrogen Dioxide

(NO2)99.79th %ile of

Max. 1 Hour Conc.

500.0 6.238

Annual Mean

Conc.

0.8 0.9

2.072 12.1

AERMOD RESULTS - Predicted maximum ground level concentration

0.06%

PM2.5 Annual Mean

Conc.

8.0

Annual Mean

Conc.

26.4%

10000506.2

98.08th %ile of

Max. 24 Hour

Conc.

14.0 0.201

Carbon

Monoxide (CO)

0.065

8.0

Running 8 - Hour

Mean

99.7th %ile of Max.

1 Hour Conc.

25.0 4.269

0.2% 78.0%

50 0.4% 28.4%

18

10.7%

26.4 200 3.2%

350 Sulphur Dioxide

(SO2)

40 2.2% 27.2%

ADMS RESULTS - Predicted maximum ground level concentration

Nitrogen Dioxide

(NO2)99.79th %ile of

Max. 1 Hour Conc.

20.0 6.448

Running 8 - Hour

Mean

500.0 5.797 505.8 10000

13.2%

Annual Mean

Conc.

10.0 0.864 10.9

5.1%


Max. 24 Hour

Conc.

14.0 0.306 14.3 50 0.6% 28.6%

Carbon

Monoxide (CO)

14.0 0.051 14.1 18 0.3%

0.06%

78.1%

PM2.5 Annual Mean

Conc.

8.0 0.051 8.1 10 0.5% 80.5%

Annual Mean

Conc.

29.3 350 1.2% 8.4%

99.2th %ile of Max.

24 Hour Conc.

10.0 2.057 12.1 125 1.6% 9.6%

0.9 5 2.1% 18.1%Volatile Organic

Compounds

Annual Mean

Conc.

0.8 0.103

Hydrogen

Chloride (HCl)

1 Hour Conc. 2.482 2.5 750 0.3% 0.3%

Hydrogen

Flouride (HF)

1 Hour Conc. 0.414 0.4 160 0.3% 0.3%

Annual Mean

Conc.

0.010 0.0 16 0.1% 0.1%

0.2%

0.1%

0.2%

0.06%

2500

180180 0.04% 0.0%Annual Mean

Conc.

0.065

4.136

Annual Mean

Conc.

0.103

4.1

0.1

1 Hour Conc.

0.1

Ammonia (NH3) 1 Hour Conc. 8.932 8.9 Ammonia (NH3)




Table 9.17: Dispersion Modelling Results - Predicted maximum concentrations at human receiver based on BAT-AEL Emission Concentration Limits (mg/Nm3) – (See Appendix A for predicted concentrations at all Air Quality Sensitive

Receivers and concentration isopleths).


Conc.

(AC)

(μg/m3)

Predicted

Process

Contribution

(PC)

(μg/m3)

Predicted

Env.

Conc.

(PEC)

(μg/m3)

AQS /

EAL

Value

µg/m³

PC

%age

of limit

value

PEC

%age

of limit

value


Conc.

(AC)

(μg/m3)

Predicted

Process

Contribution

(PC)

(μg/m3)

Predicted

Env.

Conc.

(PEC)

(μg/m3)

AQS /

EAL

Value

µg/m³

PC

%age

of limit

value

PEC

%age

of limit

value

0.2%1 Hour Conc. 0.287 0.3 160

10

1 Hour Conc. 1.7

0.052 0.90.8

0.2%

4.130 29.1

99.2th %ile of Max.

24 Hour Conc.

10.0 1.039

1.723

1.2%

0.8%

80.3%

350

0.3%

99.7th %ile of Max.

1 Hour Conc.

25.0

Annual Mean

Conc.

8.0 8.0

13.4%

AERMOD RESULTS - Predicted maximum concentration at human receiver

Nitrogen Dioxide

(NO2)

0.2%

5 1.0% 17.0%

0.1% 77.9%

10000 0.05% 5.1%

PM10

Annual Mean

Conc.

PM2.5 0.026

0.0 16

14.0 0.026

Hydrogen

Chloride (HCl)

750

0.0% 0.0%

8.3%

12511.0

14.0 18

Annual Mean

Conc.

Annual Mean

Conc.

0.005

98.08th %ile of

Max. 24 Hour

Conc.

Carbon

Monoxide (CO)

Running 8 - Hour

Mean

0.2%

28.3%14.0 0.155 14.2 50

500.0 5.271 505.3

Sulphur Dioxide

(SO2)

8.8%

Annual Mean

Conc.

0.1 180 0.1% 0.1%Annual Mean

Conc.

0.052 0.1 0.0%

ADMS RESULTS - Predicted maximum concentration at human receiver

99.79th %ile of

Max. 1 Hour Conc.

20.0 5.912 25.9 200 3.0%

0.3%

13.0%

Carbon

Monoxide (CO)

Running 8 - Hour

Mean

500.0 4.569 504.6 10000 0.05% 5.0%


Max. 24 Hour

Conc.

14.0 0.286 14.3 50 0.6% 28.6%

Annual Mean

Conc.

14.0 0.048 14.0 18 0.3% 78.0%

PM2.5 Annual Mean

Conc.

8.0 0.048 8.0 10 80.5%

99.7th %ile of Max.

1 Hour Conc.

25.0 4.078 29.1 350 1.2% 8.3%

10.0 1.901 11.9 125 1.5%

0.5%

9.5%

0.2% 0.2%

Annual Mean

Conc.

0.8 0.096 0.9 5 1.9%

99.2th %ile of Max.

24 Hour Conc.

0.1%

17.9%

Hydrogen

Chloride (HCl)

1 Hour Conc. 1.378 1.4 750

0.1%0.230 0.2 160Hydrogen

Flouride (HF)

Ammonia (NH3)

0.096

0.1%0.010 0.1%Annual Mean

Conc.

0.0 16

0.1%

0.0%

2.3 2500 0.1%0.1% 2.2962.872 2.9 2500 0.1% 1 Hour Conc.

1 Hour Conc.

2.0%

3.4% Nitrogen Dioxide

(NO2)

Annual Mean

Conc.

10.0

Sulphur Dioxide

(SO2)

Volatile Organic

Compounds

99.79th %ile of

Max. 1 Hour Conc.

20.0 6.798 26.8 200

Volatile Organic

Compounds

Hydrogen

Flouride (HF)

180

400.440 10.4 40 1.1% 26.1%

Ammonia (NH3) 1 Hour Conc.

Annual Mean

Conc.

27.0%10.0 0.805 10.8




Table 9.18: Dispersion Modelling Results - Predicted maximum ground level Group 1, 2 & 3 Metals concentrations based on BAT-AEL Emission Concentration Limits (mg/Nm3) – (See Appendix A for predicted concentrations at all

Air Quality Sensitive Receivers and concentration isopleths).


Conc.

(AC)

(μg/m3)

Predicted

Process

Contribution

(PC)

(μg/m3)

Predicted

Env.

Conc.

(PEC)

(μg/m3)

AQS /

EAL

Value

µg/m³

PC

%age

of limit

value

PEC

%age

of limit

value


Conc.

(AC)

(μg/m3)

Predicted

Process

Contribution

(PC)

(μg/m3)

Predicted

Env.

Conc.

(PEC)

(μg/m3)

AQS /

EAL

Value

µg/m³

PC

%age

of limit

value

PEC

%age

of limit

value

Annual Mean Conc 0.00003 0.00013 0.00016 0.005 2.6% 3.1% Annual Mean

Conc.

0.00003 0.00021 0.00023 0.005 4.1% 4.6%

1-Hour Conc. 0.00003 0.01787 0.01790 1.5 1.2% 1.2% 1-Hour Conc. 0.00003 0.00827 0.00830 1.5 0.6% 0.6%

Annual Mean Conc 0.00013 0.00013 0.25 0.1% 0.1% Annual Mean

Conc.

0.00021 0.00021 0.25 0.1% 0.1%

1-Hour Conc. 0.01787 0.01787 7.5 0.2% 0.2% 1-Hour Conc. 0.00827 0.00827 7.5 0.1% 0.1%


Conc.

0.00020 0.00309 0.00329 0.003 102.9% 109.6%

1-Hour Conc. 0.00020 0.26798 0.26818 15 1.8% 1.8% 1-Hour Conc. 0.00020 0.12409 0.12429 15 0.8% 0.8%

Annual Mean Conc 0.00196 0.00196 5 0.0% 0.0% Annual Mean

Conc.

0.00309 0.00309 5 0.1% 0.1%

1-Hour Conc. 0.26798 0.26798 150 0.2% 0.2% 1-Hour Conc. 0.12409 0.12409 150 0.1% 0.1%

Annual Mean Conc 0.00153 0.00196 0.00349 5 0.0% 0.1% Annual Mean

Conc.

0.00153 0.00309 0.00462 5 0.1% 0.1%


Chromium Cr VI Annual Mean Conc 0.00015 0.00020 0.00035 0.0002 98.0% 174.4% Chromium Cr VI Annual Mean

Conc.

0.00015 0.00031 0.00046 0.0002 154.4% 230.8%


Conc.

0.00007 0.00309 0.00316 0.2 1.5% 1.6%



Conc.

0.00088 0.00309 0.00397 2 0.2% 0.2%


Lead (Pb) Annual Mean Conc 0.00103 0.00196 0.00299 0.25 0.8% 1.2% Lead (Pb) Annual Mean

Conc.

0.00103 0.00309 0.00412 0.25 1.2% 1.6%


Conc.

0.00114 0.00309 0.00422 1 0.3% 0.4%



Conc.

0.00025 0.00309 0.00333 0.02 15.4% 16.7%



Conc.

0.00032 0.00309 0.00341 1 0.3% 0.3%


Vanadium (V)Vanadium (V)

Nickel (Ni)

Manganese (Mn)

Nickel (Ni)

Manganese (Mn)

Antimony (Sb)

Chromium Cr III

Copper (Cu)

Cobalt (Co)

Copper (Cu)

AERMOD RESULTS - Predicted maximum ground level concentration - Group 1, 2 & 3 Metals ADMS RESULTS - Predicted maximum ground level concentration - Group 1, 2 & 3 Metals

Arsenic (As)

Cadmium (Cd)Cadmium (Cd)

Mercury (Hg) Mercury (Hg)

Antimony (Sb)

Chromium Cr III

Cobalt (Co)

Arsenic (As)




Table 9.19 Dispersion Modelling Results - Predicted maximum Group 1, 2 & 3 Metals concentrations at human receivers based on BAT-AEL Emission Concentration Limits (mg/Nm3) – (See Appendix A for predicted concentrations

at all Air Quality Sensitive Receivers and concentration isopleths).


Conc.

(AC)

(μg/m3)

Predicted

Process

Contribution

(PC)

(μg/m3)

Predicted

Env.

Conc.

(PEC)

(μg/m3)

AQS /

EAL

Value

µg/m³

PC

%age

of limit

value

PEC

%age

of limit

value


Conc.

(AC)

(μg/m3)

Predicted

Process

Contribution

(PC)

(μg/m3)

Predicted

Env.

Conc.

(PEC)

(μg/m3)

AQS /

EAL

Value

µg/m³

PC

%age

of limit

value

PEC

%age

of limit

value

Annual Mean Conc 0.00003 0.00010 0.00013 0.005 2.0% 2.5% Annual Mean Conc 0.00003 0.00019 0.00022 0.005 3.8% 4.4%

1-Hour Conc. 0.00003 0.00574 0.00577 1.5 0.4% 0.4% 1-Hour Conc. 0.00003 0.00459 0.00462 1.5 0.3% 0.3%

Annual Mean Conc 0.00010 0.00010 0.25 0.0% 0.0% Annual Mean Conc 0.00019 0.00019 0.25 0.1% 0.1%

1-Hour Conc. 0.00574 0.00574 7.5 0.1% 0.1% 1-Hour Conc. 0.00459 0.00459 7.5 0.1% 0.1%



Annual Mean Conc 0.00157 0.00157 5 0.0% 0.0% Annual Mean Conc 0.00287 0.00287 5 0.1% 0.1%

1-Hour Conc. 0.08616 0.08616 150 0.1% 0.1% 1-Hour Conc. 0.06889 0.06889 150 0.0% 0.0%

Annual Mean Conc 0.00153 0.00157 0.00310 5 0.0% 0.1% Annual Mean Conc 0.00153 0.00287 0.00440 5 0.1% 0.1%


Chromium Cr VI Annual Mean Conc 0.00015 0.00016 0.00031 0 78.5% 154.9% Chromium Cr VI Annual Mean Conc 0.00015 0.00029 0.00044 0 143.7% 220.1%





Lead (Pb) Annual Mean Conc 0.00103 0.00157 0.00260 0.25 0.6% 1.0% Lead (Pb) Annual Mean Conc 0.00103 0.00287 0.00390 0.25 1.1% 1.6%







AERMOD RESULTS - Predicted max concentration (Group 1, 2 & 3 Metals) at human receivers ADMS RESULTS - Predicted max concentration (Group 1, 2 & 3 Metals) at human receivers

Cadmium (Cd) Cadmium (Cd)

Nickel (Ni) Nickel (Ni)

Chromium Cr III Chromium Cr III

Mercury (Hg) Mercury (Hg)

Arsenic (As) Arsenic (As)

Antimony (Sb) Antimony (Sb)

Cobalt (Co) Cobalt (Co)

Copper (Cu) Copper (Cu)

Manganese (Mn) Manganese (Mn)

Vanadium (V) Vanadium (V)




9.5 DISCUSSION OF AIR DISPERSION MODELLING RESULTS HUMAN

RECEIVERS

9.5.1 The worst-case dispersion modelling results from the Aermod dispersion models as presented in Tables 9.16 -

9.19 indicate the maximum short term and annual mean ground level pollutant concentrations. The predicted

ground level concentrations at the nearest human receivers are lower than the maximum ground level

concentrations as presented in Tables 13 - 16 (See Appendix A for predicted concentrations at all Air Quality

Sensitive Receivers and concentration isopleths). As shown in Appendix A, the worst-case ground level

concentrations are in close proximity to Proposed EfW Development.

9.5.2 In terms of the ‘Significance of Potential Environmental Effects’ the magnitude (scale of change) has been

determined by considering the impacts of the Proposed EfW Development on air quality at the worst-affected

sensitive receiver with reference to the baseline conditions and environmental assessment criteria. The worst-

case values have been used in the assessment depending on the predicted values from the AERMOD and ADMS

models.

9.5.3 A Human Health Risk Assessment (HHRA) has been produced to assess the potential health impacts due to

changes in concentrations of organic compounds for which there are no statutory air quality limit values (dioxins,

furans and dioxin-like PCBs) due to emissions from the Proposed EfW Development.

Nitrogen Dioxide (NO2)

9.5.4 The predicted NO2 emissions equate to a predicted process contribution (PC) of 6.8 μg/m3 as a 99.79th %ile of

the 1-hour NO2 concentrations at the worst affected human receiver, i.e. 3.4% of the limit value. The predicted

NO2 emissions equate to a predicted environmental concentration (PEC) of 26.8 μg/m3 as a 99.79th %ile of the

1-hour NO2 concentrations at the worst affected human receiver, i.e. 13.4% of the limit value.

9.5.5 The PC of Annual Mean NO2 concentrations of 0.81 µg/m3 is 2% of the annual mean limit value of 40 μg/m3 at

the worst affected human receiver. The PEC of Annual Mean NO2 concentrations of 10.8 µg/m3 is 27% of the

annual mean limit value of 40 μg/m3 at the worst affected human receiver (See Appendix A, Figures A1 & A2).

9.5.6 The predicted maximum ground level NO2 process contribution (PC) value of 22.3 μg/m3 as a 99.79th %ile of the

1-hour limit value is 11.2% of the limit value of 200 μg/m3. This does not occur at a sensitive human receiver

location. The maximum ground level Annual Mean NO2 PC concentration of 0.86 µg/m3 is 2.2% of the annual

mean limit value of 40 μg/m3.

9.5.7 In terms of annual mean NO2 concentrations, as impact descriptors for individual receivers as outlined in Table 1,

there will be a negligible impact on NO2 concentrations due to the Process Contribution (PC) from the

Proposed EfW Development. The long-term average concentration at receivers will be less than 75% of the

relevant Air Quality Assessment Level (AQAL) and the percentage change in concentration will be 2% of the AQAL.

Carbon Monoxide (CO)

9.5.8 The predicted CO emissions equate to a PC of <0.1% and a PEC of 5.1% of the running 8-hour mean limit value

at the worst affected human receiver. The predicted maximum ground level running 8-hour mean CO process

contribution (PC) of 6.24 μg/m3 is <0.1% of the limit value of 10,000 μg/m3. This does not occur at a sensitive

human receiver location (See Appendix A, Figure A3).

9.5.9 There will be a negligible impact on CO2 concentrations due to the Process Contribution (PC) from the

Proposed EfW Development.

Particulates (PM10 & PM2.5)

9.5.10 The predicted PM10 emissions equate to a PC of 0.29 μg/m3 as a 98.08th %ile of the 24-hour PM10 concentrations

at the worst affected human receiver, i.e. 0.6% of the limit value of 50 µg/m3. The PEC of 98.08th %ile of the 24-

hour PM10 concentrations of 14.3 µg/m3, as a maximum ground level concentration, is 28.6% of the limit value of

50 µg/m3.

9.5.11 The PC of Annual Mean PM10 concentrations of 0.05 μg/m3 is 0.3% of the annual mean limit value of 18 μg/m3

at the worst affected human receiver. The PEC of Annual Mean PM10 concentrations of 14.1 μg/m3, as a

maximum ground level concentration, is 78.1% of the annual mean limit value of 18 μg/m3 (See Appendix A,

Figures A4 & A5).

9.5.12 In terms of annual mean PM10 concentrations, as impact descriptors for individual receivers as outlined in Table

1, there will be a negligible impact on PM10 concentrations due to the Process Contribution (PC) from the

Proposed EfW Development. The long-term average concentration at receivers will be 78% of the relevant Air

Quality Assessment Level (AQAL) and the percentage change in concentration will be less than 1% of the AQAL.

9.5.13 The PC of Annual Mean PM2.5 concentrations of 0.05 μg/m3 is 0.5% of the annual mean limit value of 10 μg/m3

at the worst affected human receiver. The PEC of Annual Mean PM10 concentrations of 8 μg/m3, as a maximum

ground level concentration, is 80.5% of the annual mean limit value of 10 μg/m3.

9.5.14 There will be a negligible impact on PM2.5 concentrations due to the Process Contribution (PC) from the


Sulphur Dioxide (SO2)

9.5.15 The predicted SO2 emissions equate to a predicted process contribution (PC) of 4.13 μg/m3 as a 99.7th %ile of

the 1-hour SO2 concentrations at the worst affected human receiver, i.e. 1.2% of the limit value. The predicted

SO2 emissions equate to a predicted environmental concentration (PEC) of 29.1 μg/m3 as a 99.7th %ile of the 1-

hour SO2 concentrations at the worst affected human receiver, i.e. 8.3% of the limit value.

9.5.16 The predicted SO2 emissions equate to a predicted process contribution (PC) of 1.9 μg/m3 as a 99.2th %ile of the

24-hour SO2 concentrations at the worst affected human receiver, i.e. 1.5% of the limit value. The predicted SO2

emissions equate to a predicted environmental concentration (PEC) of 11.9 μg/m3 as a 99.2th %ile of the 24-hour

SO2 concentrations at the worst affected human receiver, i.e. 9.5% of the limit value.

9.5.17 The predicted maximum ground level SO2 predicted environmental concentration (PEC) value of 12.3 μg/m3 as

a 99.7th %ile of the 1-hour limit value is 3.5% of the limit value of 350 μg/m3. The predicted maximum ground

level SO2 predicted environmental concentration (PEC) value of 2.1 μg/m3 as a 99.2th %ile of the 24-hour limit

value is 1.7% of the limit value of 125 μg/m3. These concentrations do not occur at a sensitive human receiver

location (See Appendix A, Figures A6 & A7).

9.5.18 There will be a negligible impact on SO2 concentrations due to the Process Contribution (PC) from the





Volatile Organic Compounds (VOCs) as Benzene

9.5.19 There are no assessment levels for volatile organic compounds (VOC) emissions as they comprise a mixture of

volatile organic compounds. Furthermore, there is no information available about the proportion of benzene, or

other harmful hydrocarbon species, that may be present in the total VOC emission from the Proposed EfW

Development, although, it is likely to be a small percentage of the total. The maximum predicted annual mean

VOC ground level concentration of 0.1 µg/m3 due to emissions from the Proposed EfW Development, does not

occur at a sensitive human receiver location and this equates to 2.1% of the annual mean limit value for Benzene

of 5 µg/m3 (See Appendix A, Figure A8).

9.5.20 There will be a negligible impact on VOC concentrations due to the Process Contribution (PC) from the


Hydrogen Chloride (HCl)

9.5.21 The predicted maximum ground level hourly mean HCl process contribution (PC) of 5.4 μg/m3 is 0.7% of the limit

value of 750 μg/m3. The predicted maximum hourly mean HCl process contribution (PC) at a sensitive human

receiver location of 1.7 μg/m3 is 0.2% of the limit value of 750 μg/m3 and therefore, of negligible significance (See

Appendix A, Figure A9).

9.5.22 There will be a negligible impact on HCL concentrations due to the Process Contribution (PC) from the


Hydrogen Fluoride (HF)

9.5.23 The predicted maximum ground level hourly mean HF process contribution (PC) of 0.89 μg/m3 is 0.6% of the limit

value of 160 μg/m3. The predicted maximum hourly mean HF process contribution (PC) at a sensitive human

receiver location of 0.29 μg/m3 is 0.2% of the limit value of 160 μg/m3 and therefore, of negligible significance.

9.5.24 The predicted maximum ground level annual mean HF process contribution (PC) of 0.01 μg/m3 is 0.1% of the limit

value of 16 μg/m3. The predicted maximum annual mean HF process contribution (PC) at a sensitive human

receiver location of 0.01 μg/m3 is 0.1% of the limit value of 16 μg/m3 and therefore, of negligible significance (See

Appendix A, Figures A10 & A11).

9.5.25 There will be a negligible impact on HF concentrations due to the Process Contribution (PC) from the


Ammonia (NH3)

9.5.26 The predicted maximum ground level hourly mean NH3 process contribution (PC) of 8.9 μg/m3 is 0.4% of the limit

value of 2,500 μg/m3. The predicted maximum hourly mean NH3 process contribution (PC) at a sensitive

human receiver location of 2.87 μg/m3 is 0.1% of the limit value of 2,500 μg/m3 and therefore, of negligible

significance.

9.5.27 The predicted maximum ground level annual mean NH3 process contribution (PC) of 0.1 μg/m3 is 0.06% of the

limit value of 180 μg/m3. The predicted maximum annual mean NH3 process contribution (PC) at a sensitive

human receiver location of 0.096 μg/m3 is 0.1% of the limit value of 180 μg/m3 and therefore, of negligible

significance (See Appendix A, Figures A12 & A13).

9.5.28 There will be a negligible impact on NH3 concentrations due to the Process Contribution (PC) from the


Metals

9.5.29 Tables 9.18 & 9.19 present the results of the dispersion modelling of metal emissions as maximum ground level

concentrations and at the specific human receiver locations. The concentrations of Cadmium (Cd) & its

compounds, Mercury (Hg) & its compounds and a suite of metals including Arsenic (As), Antimony (Sb), Chromium

(Cr), Cobalt (Co), Copper (Cu), Lead (Pb), Manganese (Mn), Nickel (Ni) and Vanadium (V) have been predicted

based on the relevant BAT-AEL Emission Concentration Limits for Group 1, 2 and 3 metals.

9.5.30 A worst-case screening assessment has been carried out, with all metals (except Cadmium (Cd) and Mercury

(Hg)) modelled at a BAT-AEL emission limit value (ELV) of 0.3 mg/m3. Cadmium (Cd) and Mercury (Hg) have

modelled at a BAT-AEL emission limit value (ELV) of 0.02 mg/m3. Actual metal emission rates at comparable

facilities are normally significantly below the BAT-AEL, and as such the worst-case screening assessment is very

conservative.

9.5.31 Very low ground level concentrations have been predicted for all metals when referenced against the relevant

Environmental Assessment Level, with the exception of Arsenic (As) and Chromium (Cr VI).

9.5.32 In 2010, the Environment Agency published stringent Environmental Standards for arsenic, nickel and chromium

(VI) and the use of such stringent standards for the assessment of Group 3 metal emissions at a BAT-AEL emission

limit value (ELV) of 0.3 mg/m3 make it possible that the assessment could identify a theoretical risk that the

Environmental Standard value could be exceeded in the case of arsenic, nickel and chromium (VI). The

Environment Agency has therefore provided guidance on the assessment of Group 3 metal releases from waste

combustion processes

9.5.33 (https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/532474/LIT_

7349.pdf). Appendix A Table A1 of the guidance note outlines a summary of 34 measured values for each metal

recorded at 18 MWI and Waste Wood Co-incinerators between 2007 and 2015.




9.5.34 This document outlines the following mean emission concentrations for Arsenic (As) and Chromium (Cr VI);

• Arsenic (As) - mean emission concentration for of 0.001 mg/Nm3 (which is 300 times lower than the BAT-AEL

emission limit value (ELV) of 0.3 mg/m3)

• Chromium (Cr VI) - mean emission concentration for of 0.000035 mg/Nm3 (which is >8,500 times lower than

the BAT-AEL emission limit value (ELV) of 0.3 mg/m3)

9.5.35 On the basis of the above, the maximum ground level concentration for Arsenic (As) and Chromium (Cr VI) are

outlined in Table 9.20. Very low process contribution Arsenic (As) and Chromium (Cr VI) ground level

concentrations have been predicted when referenced against the Environment Agency guidance for typical Arsenic

(As) and Chromium (Cr VI) releases.

9.5.36 Table 9.20: Predicted maximum ground level Arsenic (As) and Chromium (Cr VI) concentrations and

concentrations at human receivers based on measured values for each metal recorded at 18 MWI and Waste

Wood Co-incinerators between 2007 and 2015.

Table 9.20: Predicted maximum ground level Arsenic (As) and Chromium (Cr VI) concentrations and concentrations at human receivers based on measured values for each metal recorded at 18 MWI and Waste Wood Co-incinerators between 2007 and 2015.

Pollutant

Period

Average

Ambient

Conc. (AC)

(μg/m3)

Predicted

Process

Contribution

(PC) (μg/m3)

Predicted

Env. Conc.

(PEC)

(μg/m3)

AQS /

EAL

Value

µg/m³

PC

%age

of limit

value

PEC

%age of

limit

value

Predicted maximum ground level concentration -

Chromium

Cr VI

Annual

Mean

0.00015 3.63E-07 0.00015 0.0002 0.2% 76.6%

Arsenic

(As)

Annual

Mean

0.00020 1.03E-05 0.00021 0.003 0.3% 7.0%

Predicted maximum concentration at human receivers

Chromium

Cr VI

Annual

Mean

0.00015 3.38E-07 0.00015 0.0002 0.2% 76.6%

Arsenic

(As)

Annual

Mean

0.00020 9.58E-06 0.00021 0.003 0.3% 7.0%

Note: The ratio of total Cr to Cr(VI) in ambient air varies, depending on local emission sources. A review of

information by the UK’s Expert Panel on Air Quality Standards (EPAQS) indicates that Cr(VI) constitutes between

3% and 33% of airborne Chromium , while the US Department of Health suggests the ratio is between 10% and

20%. EPAQS report that ambient Cr(VI) concentrations may typically constitute 3-8% of total Cr. Therefore, Cr VI

taken to be 10% of Cr III value.

9.5.37 Based on the guidance from DEFRA on the assessment of Group 3 metal releases from waste combustion

processes, there will be a negligible impact on Metals concentrations due to the Process Contribution

(PC) from the Proposed EfW Development.

Dioxins, Furans and Dioxin-like PCBs

9.5.38 Table 9.21 presents the results of the dispersion modelling of Dioxins, Furans and Dioxin-like PCB emissions as

maximum ground level concentrations and at the specific human receiver locations. The impact of the predicted

concentrations of Dioxins, Furans and Dioxin-like PCBs has been assessed in detail in the Human Health Risk

Assessment (HHRA).

Table 9.21: Predicted Dioxins, Furans and Dioxin-like PCB maximum ground level concentrations and concentrations at the specific human receiver locations.

Pollutant

Annual Mean PCDD Conc

ug/m3

Annual Mean PCB Conc

ug/m3

Maximum GLC 6.24E-10 8.11E-10

Maximum at Human Receiver Location 5.81E-10 7.55E-10

9.6 PREDICTED IMPACTS AT ECOLOGICAL RECEIVERS

9.6.1 The Environment Agency’s risk assessment guidance states that the impact of air pollutants on vegetation and

ecosystems should be assessed at the designated habitat sites within 10 km of the source. An assessment of the

impacts on designated ecological receivers within 15 Km of the Proposed EfW Development has been undertaken.

9.6.2 Table 9.22 outlines the predicted worst-case pollutant concentrations at designated ecological receivers in closest

proximity to the Proposed EfW Development. See Appendix A for predicted concentrations at all designated

ecological receivers and concentration isopleths).




Table 9.22: Predicted worst-case pollutant concentrations at designated ecological receivers in closest proximity to the Proposed EfW Development.

9.6.3 As outlined in Table 9.22, the maximum process contribution ground level annual mean NOx concentration of

0.047 µg/m3 is 0.1% of the annual mean limit value of 30 μg/m3 for the protection of vegetation. The maximum

process contribution ground level annual mean SO2 concentration of 0.012 µg/m3 is 0.1% of the annual mean limit

value of 20 μg/m3 for the protection of vegetation. The maximum process contribution ground level annual mean

NH3 concentration of 0.004 µg/m3 is 0.4% of the annual mean limit value of 1 μg/m3 for the protection of vegetation.

These maximum pollutant concentrations occur at the Hill of Barra SSSI.

9.6.4 The tables below outline the predicted ammonia concentrations, nitrogen deposition rate and acid deposition rate

at designated ecological receivers in closest proximity to the Proposed EfW Development.


Conc.

(AC)

(μg/m3)

Predicted

Process

Contribution

(PC)

(μg/m3)

Predicted

Env.

Conc.

(PEC)

(μg/m3)

AQS /

EAL

Value

µg/m³

PC

%age

of limit

value

PEC

%age

of limit

value


Conc.

(AC)

(μg/m3)

Predicted

Process

Contribution

(PC)

(μg/m3)

Predicted

Env.

Conc.

(PEC)

(μg/m3)

AQS /

EAL

Value

µg/m³

PC

%age

of limit

value

PEC

%age

of limit

value

0.010Sulphur Dioxide

(SO2)

25.1% Sulphur Dioxide

(SO2)

0.0% 25.0%

0.1%

Annual Mean

Conc.

5.0 0.012 5.01 20 0.1% 20Annual Mean

Conc.

Weekly Mean

Conc.

0.001 0.001

Hydrogen

Flouride (HF)

24-Hour Mean

Conc.

0.005 0.005 5 0.1%

0.3% 0.3%

1

24-Hour Mean

Conc.

Weekly Mean

Conc.

1.194 1

5

0.001 0.001 0.5

0.3% 119.3%0.4% 119.4% Ammonia (NH3) Annual Mean

Conc.

1.19 0.003 1.193

0.004 0.004

5.015.0

0.5 0.2%

0.1% 0.1% Hydrogen

Flouride (HF)

Nitrogen oxides

(NOx)

Annual Mean

Conc.

15.0 0.047 15.05

Ammonia (NH3) Annual Mean

Conc.

1.2 0.004

37.6%0.1% 37.6% Nitrogen oxides

(NOx)

Annual Mean

Conc.

15.0 0.04040 40 0.1%

AERMOD RESULTS - Predicted maximum concentration at ecological receiver ADMS RESULTS - Predicted maximum concentration at ecological receiver

15.04

0.2%




Table 9.23: Predicted ammonia concentrations at designated ecological receivers in closest proximity to the Proposed EfW Development.

RECEIVER NAME

Process Contribution

NH3 (µg/m3)

NH3 Background

(µg/m3)

NH3 Predicted Env.

Conc. (µg/m3)

NH3 Env. Assessment

Level (µg/m3)

%PC of NH3

Background

%PC of NH3

Assessment Level NITROGEN HABITAT

ECO 1 Hill of Barra 0.0209 1.43 1.4509 1 1.439% 2.088% No sensitive habitat or species at this

site

ECO 2 Pitcaple and

Legatsden Quarries

0.0030 1.64 1.6430 1 0.185% 0.304% No sensitive habitat or species at this

site

ECO 3 Paradise Wood 0.0007 0.79 0.7907 1 0.083% 0.066% No sensitive habitat or species at this

site

ECO 4 Pittodrie 0.0079 0.72 0.7279 1 1.083% 0.788% Broad-leaved

ECO 5 Loch of Skene SSSI 0.0020 0.91 0.9120 1 0.220% 0.200% No sensitive habitat or species at this

site

ECO 6 Loch of Skene SPA 0.0020 0.91 0.9120 1 0.220% 0.200% Bucephala clangula (North-

western/Central Europe)

ECO 7 Tilliefoure Wood 0.0007 0.72 0.7207 1 0.095% 0.068% Broad-leaved

ECO 8 Red Moss, Oldtown 0.0019 1.5 1.5019 1 0.123% 0.185% Fen marsh and swamp - lowland

ECO 9 Corby, Lily and

Bishops Lochs

0.0029 1.31 1.3129 1 0.222% 0.291% Fen marsh and swamp - lowland

ECO 10 Wartle Moss 0.0024 1.13 1.1324 1 0.215% 0.244% Standing open water not incl.

oligotrophic types

Note 1: Critical Load for Acid Deposition (kEqH+/ha/yr), Nitrogen Deposition (Kg/Ha/Yr) and Ammonia Concentrations (NH3 Conc) from SCAIL Agriculture & SCAIL Combustion and dependent on habitat type present on the designated site as outlined in the

Citation Documents for the relevant ASSI’s and SACs.

Note 2 - Assumes lichens or bryophytes (mosses) form an integral part of the habitat => use the lower 1 ug/m3 value. For all other vegetation types use 3 ug/m3




Table 9.24: Predicted nitrogen deposition rate at designated ecological receivers in closest proximity to the Proposed EfW Development.

RECEIVER NAME


Nitrogen Deposition

(kg/ha/yr)

Nitrogen Deposition

Background

(kg/ha/yr)

Nitrogen Deposition

TOTAL (kg/ha/yr)

Nitrogen Deposition

Critical Load

(kg/ha/yr)

%PC of Nitrogen

Deposition

Background

%PC of Nitrogen

Deposition Critical

Load NITROGEN HABITAT

ECO 1 Hill of Barra 0.0040 14.14 14.1440 0.028%

No sensitive habitat or species at this

site

ECO 2 Pitcaple and

Legatsden Quarries

0.0037 16.52 16.5237 0.022%


site

ECO 3 Paradise Wood 0.0016 11.9 11.9016 0.013%


site

ECO 4 Pittodrie 0.0021 15.82 15.8221 5 0.013% 0.042% Broad-leaved

ECO 5 Loch of Skene SSSI 0.0024 12.74 12.7424 0.019%


site

ECO 6 Loch of Skene SPA 0.0024 18.76 18.7624 10 0.013% 0.024% Bucephala clangula (North-

western/Central Europe)

ECO 7 Tilliefoure Wood 0.0016 15.82 15.8216 5 0.010% 0.033% Broad-leaved

ECO 8 Red Moss, Oldtown 0.0019 14.56 14.5619 10 0.013% 0.019% Fen marsh and swamp - lowland


Bishops Lochs

0.0026 13.16 13.1626 10 0.020% 0.026% Fen marsh and swamp - lowland

ECO 10 Wartle Moss 0.0028 13.3 13.3028 0.021%

Standing open water not inc

oligotrophic types






Table 9.25: Predicted acid deposition rate at designated ecological receivers in closest proximity to the Proposed EfW Development (SCAIL Combustion Screening Model Results).

RECEIVER NAME


Acid Deposition

(kEqH+/ha/yr)

Acid Deposition

Background

(kEqH+/ha/yr)

Acid Deposition

TOTAL (kEqH+/ha/yr)

Acid Deposition

Critical Load

(kEqH+/ha/yr)

%PC of Acid

Deposition

Background

%PC of Acid

Deposition Critical

Load ACID_HABITAT

ECO 1 Hill of Barra 0.0028 1.12 1.1228 0.249%


site

ECO 2 Pitcaple and

Legatsden Quarries

0.0022 1.32 1.3222 0.166%


site

ECO 3 Paradise Wood 0.0017 0.98 0.9817 0.173%


site

ECO 4 Pittodrie 0.0013 1.29 1.2913 1.16 0.101% 0.112% mixed and yew woodland

ECO 5 Loch of Skene SSSI 0.0015 1.06 1.0615 0.141%


site

ECO 6 Loch of Skene SPA 0.0012 1.06 1.0612 0.113%

Anser (Iceland/UK/Ireland)

ECO 7 Tilliefoure Wood 0.0012 1.29 1.2912 1.16 0.093% 0.103% mixed and yew woodland

ECO 8 Red Moss, Oldtown 0.0013 1.16 1.1613 0.75 0.112% 0.173% Fen marsh and swamp - lowland


Bishops Lochs

0.0012 1.05 1.0512 0.57 0.114% 0.211% Fen marsh and swamp - lowland

ECO 10 Wartle Moss 0.0012 1.11 1.1112 0.108%

Standing open water not inc

oligotrophic types



9.6.5 In terms of annual mean Ammonia (NH3) concentrations at Pittodrie SSSI, the predicted annual mean NH3

concentrations of 0.0079 µg/m3 outlined in Table 20 will be 0.78% of the critical load of 1 µg/m3. This assumes

lichens or bryophytes (mosses) form an integral part of the habitat.

9.6.6 As outlined in Table 9.24, the predicted nitrogen deposition rate at Pittodrie SSSI (0.0021 Kg/Ha/Yr) is 0.042% of

the relevant Critical Load of 5 Kg/Ha/Yr for ‘Broad leaved habitat’.

9.6.7 As outlined in Table 9.25, the predicted acid deposition rate at Pittodrie SSSI (0.0013 kEqH+/ha/yr) is 0.112% of

the relevant Critical Load of 1.16 kEqH+/ha/yr for ‘Mixed & yew woodland habitat’.

9.6.8 The maximum predicted ammonia concentrations, nitrogen deposition rate and acid deposition rate at designated

ecological receivers are well below 10% of the relevant Critical Levels (Cle) / Critical Load (CL) and hence, the

Proposed EfW Development will not have a significant impact at the nearest designated ecological

receivers or on designated species.




9.7 ODOUR CONTROL MEASURES

Odour Guidelines

9.7.1 Odour is the property of a substance that activates the human sense of smell. The human olfactory system is a

sensory system used for the detection of odours. It is highly sensitive and as such is capable of detecting extremely

low concentrations of a wide range of odorous chemicals. Due to the complex nature of odour perception by the

human olfactory system, levels of sensitivity to odour within a population will vary from person to person. In

addition, the context in which the odour occurs will affect the nuisance value of the odour.

9.7.2 To put odour concentrations and odour impact assessment criteria guidelines into context, an odour threshold of

1 ouE/m3 is the level at which an odour is detectable by 50% of screened panellists. The recognition threshold is

about 5 times this concentration i.e. 5ouE/m3. Furthermore, an odour concentration of between 5 and 10 ouE/m3

above background will give rise to a faint odour and concentrations greater than 10 ouE/m3 constitute a distinct

odour and are likely to give rise to nuisance complaints. The exposure of the population to a particular odour

consists of two factors; the concentration and the length of time that the population may perceive the odour.

9.7.3 Under Part III Section 79 (1)(d) of the Environmental Protection Act 1990, odour is declared to be a potential

statutory nuisance. However, there are no statutory limits for odour concentrations which can be used to assess

whether a nuisance has occurred. In relation to typical SEPA licence conditions for the control of odours the

licensee must ensure that all operations on-site shall be carried out in a manner such that odours do not result in

significant impairment of, or significant interference with amenities or the environment beyond the site boundary

and any method used by the licensee to control any such nuisance shall not cause environmental pollution.

9.7.4 With regard to the detection of odours by the human olfactory system, and odours which would cause annoyance

or give rise to complaint, there are a number of variables involved, which are defined by the FIDOL acronym:

• Frequency of detection - the number of exposures to an odour over a specific time period;

• Intensity - the magnitude of the perception of the odour;

• Duration - the time period during which the odour exposure occurs;

• Offensiveness - a qualitative judgement to describe the odour; and

• Location – the type of receiver will determine its sensitivity to odour, e.g. residential properties, schools, parks,

industrial locations, etc.

9.7.5 When dispersion modelling of odorous emissions is used to ascertain the extent of off-site impact the following

odour impact criteria are regarded as indicative guidelines defined on the basis of research undertaken;

• C98, 1-hour 10 ouE/m3 - complaints are highly likely and odour exposure at these levels represents an

actionable nuisance;

• C98, 1-hour 5 ouE/m3 - complaints may occur and depending on the sensitivity of the locality and nature of

the odour this level may constitute a nuisance

• C98, 1-hour 1.5 – 3 ouE/m3 - complaints are unlikely to occur and exposure below this level are unlikely to

constitute significant pollution or significant detriment to amenity unless the locality is highly sensitive or the

odour unpleasant in nature.

9.7.6 UK Guidance recommends that odour standards should vary from 1.5 – 6.0 ouE/m3 as a 98th percentile of 1-hour

averaging periods at the worst-case sensitive receiver based on the offensiveness of the odour and with

adjustments for local factors such as population density. As outlined in the Technical Guidance Note IPPC H4,

Integrated Pollution Prevention and Control (IPPC) DRAFT Horizontal Guidance for Odour Part 1 – Regulation

and Permitting as published by the Northern Ireland Environment Agency in conjunction with the Environment

Agency and the Scottish Environmental Protection Agency, “annoyance potential is the likelihood that a specific

odorous mixture will give reasonable cause for annoyance in an exposed population. Not all odours have the same

potential to cause annoyance – for example odours arising from putrescible materials, are typically considered to

be more ‘offensive’ than odours from a bakery which might be better tolerated. It should be remembered however

that ANY odour has the potential to cause offence if, for example, the odour is strong and/or exposure is frequent.

The list below (Table A6.1) is based around a ranking of industrial-type odours which was carried out in the UK

recently (as described in Appendix 1). The results are consistent with those from the Netherlands and Germany.

A larger UK study is currently underway and the table below will be reviewed in line with any different outcomes.

This ranking gives some indication of relative offensiveness. These have then been categorised as ‘low’, ‘medium’

and ‘high’ offensiveness and exposure criteria have been assigned to each category. These categories are

indicative only and do not have definite cut-off points in terms of the industry types listed. Although this ranking is

based upon the views of a number of people; within this there may be individuals who respond differently, (see

Appendix 1 – “Offensiveness”)”.

Table 9.26: Indicative odour exposure criteria for ground level concentration of mixtures of odorants

(Table A6.1 from the Technical Guidance Note IPPC H4, Integrated Pollution Prevention and Control (IPPC)

DRAFT Horizontal Guidance for Odour)




The Guidance on the Assessment of Odour for Planning (Version 1.1 - July 2018), issued by the Institute of Air

Quality Management, states that “an appropriate criterion could lie somewhere in the range of 1 to 10 ouE/m3 as

a 98th percentile of hourly mean odour concentrations”. The IAQM guidance has considered odour concentration

change descriptors together with impact descriptors for odours at the ‘most offensive’ and ‘moderately offensive’

end of the spectrum, as outlined in Tables 9.27 & 9.28. These criteria are consistent in format and concept with

other guidance, adopt the C98 as the appropriate frequency metric, encompass the 1 to 10 ouE/m3 concentration

range referred to above and also consider the potential sensitivity of different receivers. Examples of receivers that

fall into the above sensitivity categories are contained in Table 9.27.

Table 9.27: Proposed odour effect descriptors for impacts predicted by modelling – “Most Offensive”

odours (Table 6 from 2018 IAQM Odour Guidance)

Table 9.28: Proposed odour effect descriptors for impacts predicted by modelling – “Moderately Offensive”

odours (Table 7 from 2018 IAQM Odour Guidance)

Table 9.29: Receiver sensitivity to odours (Table 2 from 2018 IAQM Odour Guidance)

9.8 PROPOSED ODOUR CONTROLS

9.8.1 In relation to potential odour emission during normal operations, the mitigation measures built in to the overall

project design will be effective in preventing a detectable odour beyond the Proposed EfW Development site

boundary. Therefore, the Proposed EfW Development will be operated in accordance with typical conditions

contained within the PPC Permit.

9.8.2 In order to control odour emissions during operation of the Proposed EfW Development, the following mitigation

measures have been incorporated into the plant design:

• All waste deliveries to the Proposed EfW Development will be in enclosed vehicles and all vehicles will access

and exit the buildings via fast-acting doors;

• The reception hall for vehicles will be designed to receive waste in a variety of vehicle formats. The combustion

air for the furnace will be drawn from the waste reception hall, through the fuel conveying system and into to

the boiler air system. Vehicles will enter via an access door and once inside the reception hall, the door will

be closed to maintain a slight negative pressure inside the hall thus preventing fugitive escape of material or

odour. Therefore, this will eliminate the potential for potentially odorous air escape from the waste reception

hall and associated fuel handling and conveying areas. Any odorous compounds in the reception hall and fuel

conveyor air will be destroyed at the high combustion temperatures in the furnace.

• During very infrequent abnormal operating conditions, when the combustion unit is not available, e.g. during

a shutdown for maintenance, any potentially odorous air from waste in the waste reception hall will be captured

via the negative pressure system and the potentially odorous air will be treated in a suitably designed odour

control unit before the treated air is discharged via a roof level vent. The waste reception hall will be isolated

from the remainder of the building and it will be best practise to ensure that there is no waste stored in the

waste reception hall during any pre-planned maintenance shut-down.




• The odour control units shall be sized to take the full volume of air changes needed to ensure that the

potentially odorous areas are maintained at negative pressure, during full boiler load, all part load conditions,

and full plant shut down. Redundancy shall exist in the system to allow a unit to be taken offline for

maintenance during operations without impacting on the ability of the Proposed EfW development to treat

potentially odorous air.

• An Odour Management Plan (OMP) will be developed to ensure that operation of the Proposed EfW

Development does not result in detectable odours beyond the site boundary. The OMP will establish the

personnel responsible for managing the odour control systems and maintain documented procedures for

routine monitoring of off-site odour to ensure that all design measures are effectively operational.

• The personnel responsible for managing the odour control systems will ensure that the odour control unit will

be maintained at regular intervals and as will be outlined within the procedures of the Odour Management

Plan, the odour control unit will require regular monitoring for odour breakthrough. Such monitoring procedures

may include sniff testing or monitoring using a PID monitor at multiple points across the odour control unit to

detect elevated odour concentrations.

9.9 CUMULATIVE IMPACT ASSESSMENT

9.9.1 A cumulative impact on local air quality in the area has been assessed taking into account other potentially

significant emission sources in the Inverurie area. Nearby large-scale projects / developments to the Proposed

EfW Development include the following developments;

Current infrastructure within 5km radius:

• Thainstone Business Park and industrial complex 750m southwest. Multiple large industrial buildings.

• Ardrennan House Hotel, 1km northwest.

• Tarmac Toms Forest Asphalt Plant, 3km southwest. Operational large quarry. Aggregate lorries likely to use

the A96.

• Osprey Heights (Residential Properties), 4.5km northeast. Large section still under construction (final phase).

• Kintore Business Park, 1km south. Small Business park with 7 medium sized warehouses.

• Inverurie Hospital, 2km north.

• Breedon Kemany Concrete Products, 4.5km west. Operational quarry and concrete production facility.

• Denhead industrial/business park, 3km south. Large shopping complex, Sainsburys, car sales and industrial

warehouses.

• Shopping complex (Tesco, Lidl, PC World), 3km north.

• Industrial estate, 4km north.

• Industrial estate, 3.5km northwest (near golf course).

• Various SEPA licensed sites

9.9.2 Proposed Infrastructure Erection of 737 Dwelling houses, Business and Industrial Development, Community

Facilities including Primary School and Associated Infrastructure. Located 600m West at Crichie (Port

Elphinstone). Planning Ref: APP/2019/1489 – submitted 2019, awaiting decision

9.9.3 The application site is shown below. This site is located 400m west of the Proposed EfW Development site. A

detailed air quality impact assessment was submitted with the application. The report concludes that the overall

significance of operational phase road traffic emission impacts was determined as not significant. This was based

on the predicted impacts at discrete receiver locations in the area. Impacts on annual mean NO2, PM10 and PM2.5

concentrations were predicted to be negligible at all sensitive receivers.

9.9.4 Abattoir and Meat Production Facility, located within Thainstone Business Park. Planning Ref: APP/2018/2002. In

August 2018, Scotbeef Inverurie Limited received Full Planning Approval for their proposal to construct a new

abattoir and meat production facility at Thainstone, Inverurie. No air quality impact assessment provided with

application.

• Erection of Commercial Building, 400m south of site. Planning Ref: APP/2020/0050 – Submitted Jan 2020,

awaiting decision. No air quality impact assessment provided with application.

• Railway line developments (including a new station at Kintore). No significant additional air quality impact

expected.

• Proposed dualling of the A96. No significant additional air quality impact expected.

• Scot Proteins rendering plant at Kintore. No significant additional air quality impact expected.

9.9.5 Kintore is located approximately 3Km south of the Proposed EfW Development site. Thainstone is located

approximately 1Km south-west of the Proposed EfW Development site. Crichie is located approximately 1Km

north of the Proposed EfW Development site.




Figure 9.4: SEPA Licensed sites in proximity to the Proposed Development site

Source: https://map.environment.gov.scot/sewebmap/?layers=licensedSites

9.9.6 As outlined above, there are several existing and proposed developments in the wider area surrounding the

Proposed EfW Development site. The cumulative assessment of the emissions from these projects has been

considered based a review of the relevant available planning documentation and impact assessment, where

available. The relevant air emission sources have not been modelled cumulatively with the Proposed EfW

Development using an air dispersion model as there is insufficient data available to allow all of these potential

pollutant emission sources to be specifically modelled in a single cumulative dispersion model. However, there is

an extensive air quality monitoring network in the Inverurie area which captures all existing process emissions

from infrastructure, commercial, residential and industrial sources. Also, the background mapped estimates from

the Scottish Air Quality Database include contributions from point source emissions from all Part A licensed

activities regulated by SEPA.

9.9.7 Consequently, the cumulative impact of emissions from the Proposed EfW Development and existing or proposed

residential, commercial and industrial sources has not been underestimated in this assessment by referencing the

air quality monitoring network in the Inverurie area and the mapped background data from the Scottish Air Quality

Database. Worst-case referenced background concentrations have been added to the predicted process

contribution to allow for a thorough assessment of potential impact at human and ecological receiver locations.

9.10 SIGNIFICANCE OF IMPACT

Table 9.30: Summary of Magnitude of Impacts and Significance of Effects

Receiver Sensitivity

Description of

Impact

Magnitude of Cumulative

Impacts Probability

Significance

of Effects

Significant -

Yes/No?

Human Health High Operational

emissions

from EfW

stack to

atmosphere at

human

receiver

locations

In terms of annual mean

pollutant concentrations,

as impact descriptors for

individual receivers, there

will be a negligible

change due to the

Process Contribution.

High Negligible No

Human

Amenity

High Odour

Emissions

from Waste

Acceptance

Hall

Very low potential for

odorous emissions

Highly

unlikely

Negligible No

Ecologically

Sensitive

Receivers

High Operational

emissions

from EfW

stack to

atmosphere at

sensitive sites

The predicted max. NH3

conc is 0.78% of the

critical load of 1 µg/m3.

The predicted max.

nitrogen deposition rate

is 0.042% of the relevant

Critical Load of 5

Kg/Ha/Yr for ‘Broad

leaved habitat’. The

predicted max. acid

deposition rate is 0.112%

of the relevant Critical

Load of 1.16

kEqH+/ha/yr for ‘Mixed &

yew woodland habitat’.

High Negligible No

https://map.environment.gov.scot/sewebmap/?layers=licensedSites