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Ammonia Assessment

Falsidehill Farm, Kelso, Scotland

Client: S. Ramsey

Reference: 3303r1

Date: 13th December 2019


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Report Issue

Report Title: Ammonia Assessment - Falsidehill Farm, Kelso, Scotland

Report Reference: 3303

Field Report Version

1 2 3 4

Prepared by Ger Parry

Position Associate Director

Reviewed by Jethro Redmore

Position Director

Date of Issue 13th December 2019

Comments -

Heliport Business Park, Liverpool Road, Manchester, M30 7RU

[email protected] | 0161 706 0075 | www.red-env.co.uk

This report has been prepared by Redmore Environmental Ltd in accordance with the agreed terms and conditions of

appointment. Redmore Environmental Ltd cannot accept any responsibility for any use of or reliance on the contents of

this report by any third party.


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Executive Summary

Redmore Environmental Ltd was commissioned by S. Ramsey to undertake an Ammonia

Assessment in support of a proposed poultry unit on land associated with Falsidehill Farm, Kelso,

Scotland.

It is proposed to construct and operate a broiler breeder layer unit on land near to Falsidehill

Farm. This will comprise 4 separate buildings and provide accommodation for a total of 37,060

birds which will produce fertile eggs for broiler chick rearing.

Ammonia emissions from the proposed unit have the potential to cause impacts at ecological

designations in the surrounding area. An Ammonia Assessment was therefore undertaken to

quantify effects in the vicinity of the site.

Potential ammonia releases were defined based on the size and nature of the proposed unit.

Impacts at sensitive receptors were quantified using dispersion modelling, the results compared

with the relevant standards and assessed in accordance with the appropriate guidance.

The results of the dispersion modelling indicated impacts as a result of emissions from the

proposed unit would not significantly affect existing conditions at any designation.

Based on the assessment results, ammonia emissions are not considered a constraint to planning

consent for the proposed development.


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Table of Contents

1.0 INTRODUCTION 1

1.1 Background 1

1.2 Site Location and Context 1

2.0 AMMONIA BACKGROUND 2

2.1 Atmospheric Ammonia and Nitrogen Deposition 2

2.1 Critical Loads and Levels 2

3.0 METHODOLOGY 4

3.1 Introduction 4

3.2 Ammonia Sources 4

3.3 Ammonia Emission Rates 4

3.4 Dispersion Modelling 5

Modelling Scenarios 6

Emissions 6

Assessment Area 7

Ecological Receptors 7

Site Specific Critical Loads and Levels 9

Baseline Pollution Levels 11

Terrain Data 12

Building Effects 13

Meteorological Data 13

Roughness Length 14

Monin-Obukhov Length 14

Nitrogen Deposition 14

Acid Deposition 15

Assessment Criteria 16

Modelling Uncertainty 17

4.0 ASSESSMENT 19

4.1 Introduction 19

4.2 Ammonia 19

4.3 Nitrogen Deposition 21

4.4 Acid Deposition 24

5.0 CONCLUSION 26

6.0 ABBREVIATIONS 27


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1.0 INTRODUCTION

1.1 Background

1.1.1 Redmore Environmental Ltd was commissioned by S. Ramsey to undertake an Ammonia

Assessment in support of the proposed poultry unit on land associated with Fallsidehill

Farm, Kelso, Scotland.

1.1.1 Ammonia (NH3) emissions from the proposed unit have the potential to cause impacts at

sensitive locations. An Ammonia Assessment was therefore undertaken to quantify effects

in the vicinity of the site.

1.2 Site Location and Context

1.2.1 The proposed unit is located on land to the south-west of Falsidehill Farm, Kelso, at

National Grid Reference (NGR): 367600, 640635. Reference should be made to Figure 1

for a map of the site and surrounding area.

1.2.2 The proposals comprise the construction of a broiler breeder layer unit. This includes 4

separate buildings providing accommodation for a total of 37,060 birds which will

produce fertile eggs for broiler chick rearing. Each building will house approximately 8,500

hens and 765 cockerels.

1.2.3 The unit will operate a 48-week batch laying cycle and utilise a conventional slatted floor

system. Manure generated by the flock during occupied periods will be stored below the

slatted floors and cleaned out at the end of each cycle.

1.2.4 Each building will be ventilated by 14 uncapped ridge mounted fans in order to provide

internal temperature control and ensure that emissions are dispersed effectively to

atmosphere.

1.2.1 The proposed unit may result in NH3 emissions during normal operation. These have the

potential to cause impacts at sensitive locations within the vicinity of the site and have

therefore been assessed within this report.


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2.0 AMMONIA BACKGROUND

2.1 Atmospheric Ammonia and Nitrogen Deposition

2.1.1 NH3 is produced by the breakdown of uric acid in poultry litter. The potential for

atmospheric emissions of NH3 from poultry facilities depends largely on the type of

animals housed, the manure management system utilised during production and building

ventilation arrangements.

2.1.2 Exposure to high concentrations of NH3 can lead to direct damage to vegetation, as well

as acute toxicity in some sensitive plants. Certain species are more sensitive than others.

For example, lichens and mosses have a much lower tolerance to atmospheric NH3 than

higher plants species such as grasses and trees.

2.1.3 Atmospheric emissions of NH3 can also lead to indirect effects on vegetation. Deposition

of the nitrogen component of NH3 on to land can cause a fertilising effect which leads to

an increase in plants which thrive in a nitrogen rich environment. This may lead to

competition between species and imbalances in the natural diversity of flora within the

receiving habitat.

2.1.4 The combination of these effects can lead to changes in ecosystem structure and

function. Some of the most significant problems resulting from NH3 and nitrogen

deposition are found at nature conservation sites located in intensive agricultural areas.

2.1 Critical Loads and Levels

2.1.1 A critical load is defined by the UK Air Pollution Information System (APIS)1 as:

"A quantitative estimate of exposure to deposition of one or more pollutants,

below which significant harmful effects on sensitive elements of the environment

do not occur, according to present knowledge. The exceedance of a critical

load is defined as the atmospheric deposition of the pollutant above the critical

load."

1 UK Air Pollution Information System, www.apis.ac.uk.


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2.1.2 A critical level is defined as:

"Threshold for direct effects of pollutant concentrations according to current

knowledge. Exceedance of a critical level is defined as the atmospheric

concentration of the pollutant above the critical level."

2.1.3 A critical load refers to deposition of a pollutant, while a critical level refers to pollutant

concentrations in the atmosphere (which usually have direct effects on vegetation or

human health).

2.1.4 When pollutant loads (or concentrations) exceed the critical load or level it is considered

that there is a potential risk of harmful effects. The excess over the critical load or level is

termed the exceedence. A larger exceedence is often considered to represent a greater

risk of harm.

2.1.5 Maps of critical loads and levels and their exceedences have been used to show the

potential extent of pollution damage and aid in developing strategies for reducing

pollution. Decreasing deposition below the critical load is seen as means for preventing

the risk of damage. However, even a decrease in the exceedence may infer that less

harm will occur.

2.1.6 Table 1 presents the critical levels for the protection of vegetation for pollutants considered

within this assessment.

Table 1 Critical Levels for the Protection of Vegetation

Pollutant Critical Level

Concentration (µg/m3) Averaging Period

NH3 1 Where lichens and bryophytes are present (where they form a key part of the ecosystem integrity)

3 Other vegetation

2.1.7 Critical loads have been designated within the UK based on the sensitivity of the

receiving habitat and have been identified for the relevant designations considered

within the assessment in Section 3.4.


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3.0 METHODOLOGY

3.1 Introduction

3.1.1 The proposed poultry unit may result in NH3 emissions during normal operation. These were

assessed in accordance with the following stages:

x Identification of NH3 sources;

x Identification of NH3 emission rates;

x Dispersion modelling of NH3 emissions; and,

x Comparison of modelling results with relevant criteria.

3.1.2 The following Sections outline the methodology and inputs used for the assessment.

3.2 Ammonia Sources

3.2.1 The proposed unit will be ventilated via 56 six uncapped ridge mounted fans (14 per

building). There is the potential for releases of NH3 from the fans during normal operation

of the unit. As such, emissions from these sources have been considered throughout the

assessment.

3.3 Ammonia Emission Rates

3.3.1 NH3 emission rates for use in the assessment were obtained from the Environment Agency

(EA) Intensive Farming Guidance Note2. This indicated a maximum NH3 emission rate of

0.29kgNH3/animal place/yr for layers housed within buildings which utilise a deep pit

manure system. The total release rate for each building was calculated by multiplying this

value by the number of birds that will be housed. The NH3 emission rates for the proposed

unit are summarised in Table 2.

2 Intensive Farming Guidance Note, EA, 2012.


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Table 2 NH3 Emission Rate - Proposed Poultry Unit

Building NH3 Emission Rate (kg/bird place/yr)

Number of Birds NH3 Emission Rate (kg/yr)

NH3 Emission Rate (g/s)

1 0.29 9,265 2,686.85 0.085

2 0.29 9,265 2,686.85 0.085

3 0.29 9,265 2,686.85 0.085

4 0.29 9,265 2,686.85 0.085

Total - 37,060 10,747.40 0.341

3.4 Dispersion Modelling

3.4.1 Dispersion modelling was undertaken using ADMS-5.2 (v5.2.4.0), which is developed by

Cambridge Environmental Research Consultants (CERC) Ltd. ADMS-5 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.

3.4.2 The model utilises hourly meteorological data to define conditions for plume rise, transport

and diffusion. It estimates the concentration for each source and receptor combination

for each hour of input meteorology and calculates user-selected long-term and short-

term averages.

3.4.3 The model requires input data that details the following parameters:

x Assessment area;

x Process conditions;

x Pollutant emission rates;

x Terrain information;

x Building dimensions;

x Meteorological data;

x Roughness length (z0); and,

x Monin-Obukhov length.


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3.4.4 These are detailed in the following Sections.

Modelling Scenarios

3.4.5 The scenarios considered in the modelling assessment are summarised in Table 3.

Table 3 Assessment Scenarios

Parameter Modelled As

Long Term Short Term

NH3 Annual mean -

Nitrogen deposition Annual deposition

Acid deposition Annual deposition

3.4.6 Predicted pollutant concentrations were summarised in the following formats:

x Process contribution (PC) - Predicted pollutant level as a result of emissions from the

proposed poultry unit only; and

x Predicted environmental concentration (PEC) - Total predicted pollutant level as a

result of emissions from the proposed poultry unit and the existing baseline.

3.4.7 Predicted ground level pollutant concentrations and deposition rates were compared

with the relevant Critical Levels and Critical Loads. These criteria are collectively referred

to as Environmental Quality Standards (EQSs).

Emissions

3.4.8 The data shown in Table 2 was utilised with additional information provided by S. Ramsey

to define emissions within the dispersion model.

3.4.9 Emissions from the ridge mounted fans associated with the unit were represented by a

total of 56-point sources within the model setup (14 on each building). A summary of the

inputs is provided in Table 4.


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Table 4 Ridge Mounted Fans Model Input

Buildings Unit Value

1 to 4 Source type - Point

Positions - As shown on Figure 2

Number of sources - 56 (14 per building)

Source height (per source) m 5.6

Source diameter (per source) m 1.0

Efflux velocity (per source) m/s 11.3

Emission temperature (per source) qC 15.0

Emission rate (per source) g/s 0.00609

3.4.10 Emissions were assumed to be constant, 24-hours per day, 365-days per year. This will

overestimate impacts associated with emissions as it does not take into account periods

when the buildings are unoccupied between laying cycles. As such, use of the stated

inputs is considered to provide a robust and worst-case assessment of potential effects.

Assessment Area

3.4.11 The assessment area was defined based on the location of the proposed unit,

anticipated pollutant dispersion patterns and the positioning of sensitive receptors.

Ambient concentrations were predicted over NGR: 365440, 638320 to 369940, 642820.

One Cartesian grid with a resolution of 20m was used within the model to produce data

suitable for contour plotting using the Surfer software package.

3.4.12 Reference should be made to Figure 2 for a graphical representation of the assessment

grid extents.

Ecological Receptors

3.4.13 Atmospheric emissions of NH3 from the proposed poultry unit have the potential to impact

on receptors of ecological sensitivity within the vicinity of the site. An Environmental

Impact Assessment (EIA) Screening Opinion prepared by Scottish Borders Council in

relation to the proposals (ref: 19/01496/SCR) indicates that the following sites of


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ecological nature conservation importance are located in the vicinity of the site and

should be considered as part of the assessment:

x Hareheugh Craigs Site of Special Scientific Interest (SSSI);

x Lurgie Loch SSSI;

x Hume Craigs Local Wildlife Site (LWS); and,

x Sweethope Hill which represents a provisional Local Biodiversity Site (LBS).

3.4.14 For the purpose of the dispersion modelling, discrete receptors were placed at the closest

points of each designation to the site in order to ensure the maximum potential impact

was predicted. These are summarised in in Table 5.

Table 5 Ecological Receptor Locations

Receptor Designation NGR (m)

X Y

E1 Lurgie Loch SSSI 367302.9 639362.1






E7 Hareheugh Craigs SSSI 368658.8 639954.7





E12 Hume Craigs LWS 369721.5 641785.6

E13 Hume Craigs LWS 369743.1 641716.2

E14 Hume Craigs LWS 369764.7 641640.8

E15 Hume Craigs LWS 369812.9 641550.5

E16 Hume Craigs LWS 369807.7 641454.2


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Receptor Designation NGR (m)

X Y

E17 Sweethope Hill LBS 369637.8 639974.9



3.4.15 Reference should be made to Figure 3 for a map of the ecological receptor locations.

Site Specific Critical Loads and Levels

3.4.16 Critical loads and levels have been designated within the UK based on the sensitivity and

relevant features of the receiving habitat. A review of the APIS3 and Multi-Agency

Geographic Information for the Countryside (MAGIC)4 websites was undertaken in order

to identify the most suitable habitat description and associated critical load for the area

of each designation considered within the assessment.

3.4.17 The relevant critical levels for NH3 are summarised in Table 6.

Table 6 Receptor Sensitivity to NH3 Concentrations

Receptor Potential for Presence of Lichens and Bryophytes?

Critical Level for NH3 (µg/m3)

E1 Lurgie Loch Yes 1






E7 Hareheugh Craigs No -(a)


3 http://www.apis.ac.uk/.

4 Multi-Agency Geographic Information for the Countryside, www.magic.gov.uk.


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Receptor Potential for Presence of Lichens and Bryophytes?

Critical Level for NH3 (µg/m3)




E12 Hume Craigs Yes 1





E17 Sweethope Hill Yes 1



NOTE: (a) The site is designated due to geological interest and therefore has no qualifying ecological features

that are sensitive to NH3.

3.4.18 It should be noted that the EQSs shown in Table 6 assume that lichens and bryophytes

may be present at all designations which have qualifying ecological features. This

ensured a robust and worst-case assessment.

3.4.19 The relevant critical loads for nitrogen deposition are presented in Table 7.

Table 7 Critical Loads for Nitrogen Deposition

Receptors Feature APIS Habitat Critical Load (kgN/ha/yr)

Low High

E1 to E6 Lowland Fens (Basin Fen) Valley mires, poor fens and transition mires

10 15

E7 to E11 -(a) -(a) -(b) -(b)

E12 to E16 Acid grassland Alpine and subalpine grasslands

5 10


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Receptors Feature APIS Habitat Critical Load (kgN/ha/yr)

Low High

E17 to E19 Acid grassland Alpine and subalpine grasslands

5 10

NOTE: (a) The site is designated due to geological interest and therefore has no qualifying ecological

features.

(b) No critical loads are assigned due to the absence of qualifying ecological features and associated

habitats.

3.4.20 The relevant acid deposition critical loads are presented in Table 8.

Table 8 Critical Loads for Acid Deposition

Receptors Feature APIS Habitat Acid Critical Load (keq/ha/yr)

CLMinN CLMaxS CLMaxN

E1 to E6 Purple Moor Grass and Rush Pastures (Basin Fen)

Acid grassland 0.223 0.81 1.248

E7 to E11 -(a) -(a) -(a) -(b) -(b)

E12 to E16 Acid grassland Acid grassland 0.223 0.81 1.033

E17 to E19 Acid grassland Acid grassland 0.223 0.81 1.033

NOTE: (a) The site is designated due to geological interest and therefore has no qualifying ecological

features.

(b) No critical loads are assigned due to the absence of qualifying ecological features and associated

habitats.

Baseline Pollution Levels

3.4.21 Background NH3 concentrations and nitrogen/ acid deposition rates at each ecological

receptor location were obtained from the APIS website using the 'site relevant critical

load search' or 'search by location' function. These are summarised in Table 9.


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Table 9 Baseline NH3 Concentrations and Nitrogen/ Acid Deposition Rates

Receptor

Annual Mean NH3 Conc. (µg/m3)

Baseline Deposition Rate

Nitrogen (kgN/ha/yr)

Acid (keq/ha/yr)

Nitrogen Sulphur

E1 Lurgie Loch 1.55 14.14 1.01 0.20

E2 Lurgie Loch 1.55 14.14 1.01 0.20

E3 Lurgie Loch 1.55 14.14 1.01 0.20

E4 Lurgie Loch 1.55 14.14 1.01 0.20

E5 Lurgie Loch 1.55 14.14 1.01 0.20

E6 Lurgie Loch 1.55 14.14 1.01 0.20

E7 Hareheugh Craigs 1.55 14.14 1.01 0.20





E12 Hume Craigs 1.72 15.96 1.14 0.22

E13 Hume Craigs 1.72 15.96 1.14 0.22

E14 Hume Craigs 1.72 15.96 1.14 0.22

E15 Hume Craigs 1.72 15.96 1.14 0.22

E16 Hume Craigs 1.72 15.96 1.14 0.22

E17 Sweethope Hill 1.55 14.14 1.01 0.20

E18 Sweethope Hill 1.55 14.14 1.01 0.20

E19 Sweethope Hill 1.55 14.14 1.01 0.20

Terrain Data

3.4.22 Ordnance Survey OS Terrain 50 data was included in the model for the site and

surrounding area in order to take account of the specific flow field produced by

variations in ground height throughout the assessment extents. This was pre-processed

using the method suggested by CERC.


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Building Effects

3.4.23 The dispersion of substances released from elevated sources can be influenced by the

presence of buildings close to the emission point. Structures can interrupt the wind flows

and cause significantly higher ground-level concentrations close to the source than

would arise in the absence of the buildings.

3.4.24 The building parameters used in the dispersion model are outlined in Table 10.

Table 10 Building Parameters

Building ID NGR Height (m) Length (m) Width (m) Angle (˚)

X Y

B1 367565.8 640628.0 5.1 102.5 16.1 153.8

B2 367555.6 640674.1 3.2 10.7 6.0 153.8

B3 367584.7 640640.6 5.1 108.6 16.1 153.8

B4 367575.9 640683.5 3.2 10.7 6.0 153.8

B5 367605.9 640647.2 5.1 102.5 16.1 153.8

B6 367597.1 640690.6 3.2 4.6 6.0 153.8

B7 367627.1 640654.1 5.1 96.4 16.1 153.8

Meteorological Data

3.4.25 Meteorological data used in the assessment was taken from Edinburgh meteorological

station over the period 1st January 2013 to 31st December 2017 (inclusive). This observation

station is located at NGR: 316116, 671394, which is approximately 63km north-west of the

proposed poultry unit. It is anticipated that conditions would be reasonably similar over a

distance of this magnitude. The data was therefore considered suitable for an assessment

of this nature.

3.4.26 All meteorological records used in the assessment were provided by Atmospheric

Dispersion Modelling Ltd, which is an established distributor of data within the UK.

Reference should be made to Figure 4 for wind roses of the utilised meteorological values.


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Roughness Length

3.4.27 The z0 is a modelling parameter applied to allow consideration of surface height

roughness elements. A z0 of 0.3m was used within the model to describe the dispersion

extents and the meteorological site. This value is considered appropriate for the

morphology of both areas and is suggested within ADMS-5 as being suitable for

'agricultural areas (max)'.

Monin-Obukhov Length

3.4.28 The Monin-Obukhov length provides a measure of the stability of the atmosphere. A

minimum Monin-Obukhov length of 1m was used to describe the modelling extents. This

value is considered appropriate for the nature of the area and is suggested within ADMS-

5 as being suitable for a 'rural area'.

3.4.29 A minimum Monin-Obukhov length of 10m was used to describe the meteorological site.

This value is considered appropriate for the nature of the area and is suggested within

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

Nitrogen Deposition

3.4.30 Nitrogen deposition rates were calculated using the conversion factors provided within

Environment Agency (EA) document 'Technical Guidance on Detailed Modelling

approach for an Appropriate Assessment for Emissions to Air AQTAG 06'5. Predicted

pollutant concentrations were multiplied by the relevant deposition velocity and

conversion factor to calculate the speciated dry deposition flux. The conversion factors

used for the determination of nitrogen deposition are presented within Table 11.

5 Technical Guidance on Detailed Modelling approach for an Appropriate Assessment for Emissions to Air AQTAG

06, EA, 2014.


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Table 11 Conversion Factors to Determine Dry Deposition Flux for Nitrogen Deposition

Pollutant Deposition Velocity (m/s) Conversion Factor (μg/m2/s to kg/ha/yr of pollutant species) Grassland Forest

NH3 0.020 0.030 260

3.4.31 The relevant deposition velocity for each ecological receptor was selected from Table 11

based on the vegetation type present within the designation.

Acid Deposition

3.4.32 Predicted ground level NH3 concentrations were converted to kilo-equivalent ion

depositions (keq/ha/yr) for comparison with the critical load for acid deposition at each

of the identified ecological receptors. The conversion to units of equivalents, a measure

of the potential acidifying effect of a species, was undertaken using the standard

conversion factors shown in Table 12.

Table 12 Conversion Factors to Determine Dry Deposition Flux for Acid Deposition

Pollutant Deposition Velocity (m/s) Conversion Factor (μg/m2/s to keq/ha/yr of pollutant species) Grassland Forest

NH3 0.02 0.03 18.5

3.4.33 The following formula was used to calculate predicted PCs as a proportion of the critical

load function where PECs were identified to be greater than the CLminN value.

PC as %CL function = ((PC of S+N deposition)/CLmaxN) x 100

3.4.34 The above formula was obtained from the APIS website6.

6 http://www.apis.ac.uk/.


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Assessment Criteria

3.4.35 The Scottish Environment Protection Agency (SEPA) 'Guidance on the Assessment of

Ammonia Emissions from PPC Intensive Agricultural Installations on Designated

Conservation Sites'7 indicates that for poultry units which meet or exceed the 40,000 bird

place permitting threshold, as defined in the Pollution Prevention and Control (Scotland)

Regulations (2012), refusal of a permit would be difficult to justify where detailed

modelling demonstrates that PCs are below 10% of the critical load or level at Special

Protection Areas (SPAs), Special Areas of Conservation (SACs) and Ramsar sites. It is

recognised that the number of bird places associated with the proposed poultry unit at

Falsidehill Farm is below the stated threshold. However, the SEPA criteria is still considered

to be relevant and has been utilised as part of interpretation of the modelling results in

the context of this assessment.

3.4.36 In addition to the stated SEPA guidance, the EA document 'Intensive farming risk

assessment for your environmental permit'8 provides screening thresholds for the

assessment of predicted PCs to atmospheric NH3 concentrations and nitrogen deposition

rates at ecological designations. A summary of the relevant criteria is provided in Table

13.

Table 13 EA Screening Thresholds

Designation Lower Threshold (%) Upper Threshold (%)

SPAs, SACs and Ramsar sites 4 20

SSSIs 20 50

National Nature Reserves (NNRs), Local Nature Reserves (LNRs), Ancient Woodland (AW) and other locally designated sites

100 100

3.4.37 The guidance indicates that if predicted PCs are less than the lower threshold of the

relevant critical level or load, no further detailed assessment of potential impacts is

required.

7 Guidance on the Assessment of Ammonia Emissions from PPC Intensive Agricultural Installations on Designated

Conservation Sites

8 https://www.gov.uk/guidance/intensive-farming-risk-assessment-for-your-environmental-permit.


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3.4.38 If predicted PCs are above the upper threshold of the relevant critical level or load,

further detailed modelling is required in order to quantify potential effects.

3.4.39 If predicted PCs are above the lower threshold but less than the upper threshold of the

relevant critical level or load at a SAC, SPA, Ramsar site or SSSI, further detailed

assessment may be required in order to determine the potential for in-combination

effects due to other agricultural installations in the vicinity of the site.

3.4.40 In order to provide a robust appraisal of potential impacts, interpretation of the modelling

results has been undertaken with reference to the stated SEPA and EA criteria.

Modelling Uncertainty

3.4.41 Uncertainty in dispersion modelling predictions can be associated with a variety of

factors, including:

x Model uncertainty - due to model limitations;

x Data uncertainty - due to errors in input data, including emission estimates,

operational procedures, land use characteristics and meteorology; and,

x Variability - randomness of measurements used.

3.4.42 Potential uncertainties in the model results were minimised as far as practicable and

worst-case inputs used in order to provide a robust assessment. This included the

following:

x Choice of model - ADMS-5 is a commonly used atmospheric dispersion model and

results have been verified through a number of studies to ensure predictions are as

accurate as possible;

x Meteorological data - Modelling was undertaken using five annual meteorological

data sets from a local observation station to the site in order to take account of local

conditions;

x Surface characteristics - The z0 and Monin-Obukhov length were determined for

both the dispersion and meteorological sites based on the surrounding land uses

and guidance provided by CERC. Terrain data was included and processed using

the method outlined by CERC;


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x Proposed operating conditions - Operational parameters were supplied by the

applicant to describe the activities that will be undertaken at the unit. As such, these

are considered to be representative of likely operating conditions;

x Emission rates - Emission rates were derived from industry best practice guidance. As

such, they are considered to be representative of potential releases during normal

operation;

x Receptor locations - A Cartesian Grid was included in the model in order to provide

suitable data for contour plotting. Receptor points were also included at sensitive

locations to provide additional consideration of these areas; and,

x Variability - All model inputs are as accurate as possible and worst-case conditions

were considered as necessary in order to ensure a robust assessment of potential

pollutant concentrations.

3.4.43 Results were considered in the context of the relevant EQSs and EA criteria. It is

considered that the use of the stated measures to reduce uncertainty and the use of

worst-case assumptions when necessary has resulted in model accuracy of an

acceptable level.


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4.0 ASSESSMENT

4.1 Introduction

4.1.1 Dispersion modelling was undertaken using the input data specified previously. The results

are summarised in the following Sections.

4.2 Ammonia

4.2.1 Predicted annual mean NH3 PCs at the ecological receptor locations are summarised in

Table 14.

Table 14 Predicted Annual Mean NH3 Concentrations

Receptor Predicted Annual Mean NH3 PC (µg/m3)

2013 2014 2015 2016 2017

E1 Lurgie Loch SSSI 0.050 0.051 0.038 0.056 0.050






E7 Hareheugh Craigs SSSI 0.041 0.040 0.041 0.060 0.049





E12 Hume Craigs LWS 0.180 0.162 0.186 0.205 0.227

E13 Hume Craigs LWS 0.182 0.165 0.191 0.206 0.230

E14 Hume Craigs LWS 0.182 0.167 0.195 0.205 0.231

E15 Hume Craigs LWS 0.177 0.166 0.196 0.201 0.227


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Receptor Predicted Annual Mean NH3 PC (µg/m3)

2013 2014 2015 2016 2017

E16 Hume Craigs LWS 0.175 0.169 0.201 0.201 0.228

E17 Sweethope Hill LBS 0.030 0.032 0.040 0.045 0.038



4.2.2 Maximum predicted annual mean NH3 concentrations at the receptor locations are

summarised in Table 15. Reference should be made to Figure 5 for a graphical

representation of predicted annual mean NH3 concentrations throughout the assessment

extents using the 2017 meteorological data set, which resulted in the maximum impacts.

Table 15 Maximum Predicted Annual Mean NH3 Concentrations

Receptor Predicted Annual Mean NH3 Concentration (µg/m3)

Proportion of EQS (%)

PC PEC PC PEC

E1 Lurgie Loch SSSI 0.056 1.606 5.6 160.6






E7 Hareheugh Craigs SSSI 0.060 1.610 - -





E12 Hume Craigs LWS 0.227 1.947 22.7 194.7

E13 Hume Craigs LWS 0.230 1.950 23.0 195.0


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Receptor Predicted Annual Mean NH3 Concentration (µg/m3)


PC PEC PC PEC

E14 Hume Craigs LWS 0.231 1.951 23.1 195.1

E15 Hume Craigs LWS 0.227 1.947 22.7 194.7

E16 Hume Craigs LWS 0.228 1.948 22.8 194.8

E17 Sweethope Hill LBS 0.045 1.595 4.5 159.5



4.2.3 As shown in Table 15, the predicted PC proportion of the EQS was less than 10% at Lurgie

Loch SSSI and 100% at all local sites. As such, in accordance with the stated SEPA and EA

guidance, no further assessment of potential impacts as a result of NH3 emissions from the

unit is required.

4.2.4 It should be noted that PECs are predicted to exceed the EQSs at all receptor locations

as a base condition.

4.3 Nitrogen Deposition

4.3.1 Predicted annual nitrogen deposition at the receptor locations are summarised in Table

16.

Table 16 Predicted Annual Nitrogen PC Deposition Rates

Receptor Predicted Annual PC Nitrogen Deposition Rate (kgN/ha/yr)

2013 2014 2015 2016 2017







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Page 22

Receptor Predicted Annual PC Nitrogen Deposition Rate (kgN/ha/yr)

2013 2014 2015 2016 2017







E12 Hume Craigs LWS 0.938 0.843 0.967 1.066 1.179

E13 Hume Craigs LWS 0.945 0.856 0.992 1.070 1.194

E14 Hume Craigs LWS 0.946 0.867 1.014 1.069 1.203

E15 Hume Craigs LWS 0.919 0.863 1.019 1.043 1.182

E16 Hume Craigs LWS 0.911 0.879 1.043 1.043 1.186




4.3.2 Maximum predicted annual nitrogen deposition rates at the receptor locations are

summarised in Table 17.

Table 17 Maximum Predicted Annual Nitrogen Deposition Rates

Receptor Predicted Annual Nitrogen Deposition Rate (kgN/ha/yr)


PC PEC Low EQS High EQS

PC PEC PC PEC

E1 Lurgie Loch SSSI 0.440 14.580 4.4 145.8 2.9 97.2




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Receptor Predicted Annual Nitrogen Deposition Rate (kgN/ha/yr)


PC PEC Low EQS High EQS

PC PEC PC PEC




E7 Hareheugh Craigs SSSI 0.310 14.450 - - - -





E12 Hume Craigs LWS 1.179 17.139 23.6 342.8 11.8 171.4

E13 Hume Craigs LWS 1.194 17.154 23.9 343.1 11.9 171.5

E14 Hume Craigs LWS 1.203 17.163 24.1 343.3 12.0 171.6

E15 Hume Craigs LWS 1.182 17.142 23.6 342.8 11.8 171.4

E16 Hume Craigs LWS 1.186 17.146 23.7 342.9 11.9 171.5

E17 Sweethope Hill LBS 0.232 14.372 4.6 287.4 2.3 143.7





guidance, no further detailed assessment of potential impacts as a result of nitrogen

deposition is required.

4.3.4 It should be noted that PECs are predicted to exceed the EQS at all receptor locations as

a base condition.


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4.4 Acid Deposition

4.4.1 Predicted annual acid PC deposition rates are summarised in Table 18.

Table 18 Predicted Annual PC Acid Deposition Rates

Receptor Predicted Annual PC Acid Deposition Rate (keq/ha/yr)

2013 2014 2015 2016 2017












E12 Hume Craigs LWS 0.067 0.060 0.069 0.076 0.084

E13 Hume Craigs LWS 0.067 0.061 0.071 0.076 0.085

E14 Hume Craigs LWS 0.067 0.062 0.072 0.076 0.086

E15 Hume Craigs LWS 0.065 0.061 0.072 0.074 0.084

E16 Hume Craigs LWS 0.065 0.063 0.074 0.074 0.084




4.4.2 Maximum predicted annual acid deposition rates at the receptor locations are

summarised in Table 19.


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Table 19 Predicted Annual Acid Deposition Rates

Receptor Maximum Predicted Annual Acid PC Deposition Rate (keq/ha/yr)








E7 Hareheugh Craigs SSSI 0.022 -





E12 Hume Craigs LWS 0.084 8.1










guidance, no further detailed assessment of potential impacts as a result of acid

deposition is required.


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Page 26

5.0 CONCLUSION

5.1.1 Redmore Environmental Ltd was commissioned by S. Ramsey to undertake an Ammonia

Assessment in support of a proposed poultry unit on land associated with Fallsidehill Farm,

Kelso, Scotland.

5.1.2 It is proposed to construct and operate a broiler breeder layer unit. This will comprise 4

separate buildings and provide accommodation for 37,060 birds which will produce fertile

eggs for broiler chick rearing.

5.1.3 Emissions of NH3 from the proposed unit have the potential to cause impacts at sensitive

ecological locations. An Ammonia Assessment was therefore undertaken to quantify

effects in the vicinity of the site.

5.1.4 Potential NH3 releases were defined based on the size and nature of the proposed unit.

Impacts at sensitive receptors were quantified using dispersion modelling, the results

compared with the relevant critical levels/ loads and assessed in accordance with the

appropriate guidance.

5.1.5 The results of the dispersion modelling indicated impacts as a result of emissions from the

proposed unit would not significantly affect existing conditions at any designation.

5.1.6 Based on the assessment results, NH3 emissions are not considered a constraint to

planning consent for the proposed development.


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6.0 ABBREVIATIONS

AW Ancient Woodland

CERC Cambridge Environmental Research Consultants

DEFRA Department for Environment, Food and Rural Affairs

EA Environment Agency

EC European Commission

LBS Local Biodiversity Site

LNR Local Nature Reserve

LWS Local Wildlife Site

MAGIC Multi-Agency Geographic Information for the Countryside

NNR National Nature Reserve

NGR National Grid Reference

NH3 Ammonia

PC Process Contribution

PEC Predicted Environmental Concentration

SAC Special Areas of Conservation

SPA Special Protection Area

SSSI Site of Special Scientific Interest

z0 Roughness length

%ile Percentile


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Figures

ammonia assessment falsidehill farm, kelso,...

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