Insight into the guidance and further discussion on particular chapters by the authors of the guidance. Presented by: Dr James Riley, Sarah Horrocks and Phil Davidson 24th May 2017

1. Assessing air quality impacts
on habitats
CIEEM/IAQM Guidance Consultation
26 May 2017 1
Dr James Riley, AECOM
Sarah Horrocks, Atkins
Phil Davidson, WSP (ex PBA)

2. Introduction
Dr. James Riley, AECOM – ecologist, 10 year focus on
traffic-related air quality for projects and Local Plans, also
point-source permitting. PI, JR and DCO examinations.
CIEEM member.
Sarah Horrocks, Atkins – air quality specialist, industrial
permit applications and road/planning applications.
Evidence at PI and DCO examinations. IAQM member.
Philip Davidson, WSP (formerly PBA) – ecologist,
industrial permit applications. PI work. CIEEM member.
26 May 2017 2
Speakers

3. Introduction
Initial 3-person core, plus reviewers
(Dr. Caroline Chapman, DTA; Dr. Nick Betson, RPS)
Co-authorship of all chapters
CIEEM & IAQM members working group
CIEEM PSC and IAQM Committee involvement
Statutory body consultation (via AQTAG forum)
Now - IAQM/CIEEM members consultation
26 May 2017 3
Drafting process

4. What we hope to achieve
Key messages from 2015 meeting:
• Misapplication of screening criteria as significance
criteria - especially 1%
• Limited knowledge among ecologists of critical levels
and critical loads and what they imply
• Need clear and concise advice and not repeat or
contradict what is already out there!
• Roadmap for users
26 May 2017 4
Bridging the gap

5. Key Challenges
• Large differences in level of technical knowledge
between disciplines and among practitioners
• Different legislation and interpretation in England,
Wales, Scotland and NI
• The Ashdown Forest Case and implications for
screening and assessment of cumulative impacts
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Providing clear direction

6. Chapters 2 to 4
Calculating AQ impacts
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Sarah Horrocks

7. Ch2 – AQ & Ecology
• High level overview of pollutants and their effects on
ecosystems / vegetation
• Outlines key pollutants emission sources, legislation
• Ecological impacts – direct toxicity, indirect (nutrient
/acid deposition)
• NOx, SO2, NH3 (intensive farming) - critical levels
• Nitrogen and acid deposition - critical loads
• Other pollutants - HCl, HF – not in detail
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Main contents

8. Key processes
26 May 2017 8

9. Critical levels and loads
• Critical level:
• applies to atmospheric pollutant concentrations
• a level fixed on the basis of scientific knowledge, above
which direct adverse effects may occur on some receptors,
such as trees, other plants or natural ecosystems but not
on humans (EU Directive)
• Critical load:
• applies to nutrient or acid deposition rate (flux)
• a quantitative estimate of exposure to one or more
pollutants below which significant harmful effects on
specified sensitive elements of the environment
do not occur according to present knowledge (UNECE)
26 May 2017 9
Definitions

10. Ch 3 - Collaboration
• When this can and should take place – 3 stages
• Who can do what and when:
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Main contents
• Share
information
• Selection of
sites
Project
Initiation
• Receptor
locations
• Assessment
criteria
Air quality
assessment • Handover of
results
• Understand
uncertainty
Ecological
assessment

11. Chapter 3 - Collaboration
• Collaboration can help with:
• Avoiding repetition of tasks,
• Gaining additional information about the site
• Ensuring consistency across assessments
• Helping with selection of values from APIS
• Finding out early about stakeholder concerns
• Improving understanding of each others’ needs
• Cross checking/reporting of results in e.g. HRA
26 May 2017 11
Benefits

12. Ch 4 – AQ Calculations
• Different approaches for different application stages
(permitting vs planning)
• Different screening criteria for different scheme
types (industrial vs roads vs agriculture)
• Different assessment criteria for different habitat
types in different conditions and locations
• Not all guidance that is applied is publicly available
(e.g. AQTAG)
• Understanding when an AQ specialist can screen
out and where potential effects cannot be dismissed
26 May 2017 12
AQ assessment challenges

13. Ch 4 – AQ Calculations
• Approaches to assessment and available guidance
• Scoping – is an assessment required?
• Screening – simple model to determine
insignificance, rule out impacts early on
• Detailed – advanced modelling to provide robust
answer, calculate deposition from concentration
• Application of “screening” criteria
• Process contributions (PC) and predicted
environmental concentrations (PEC)
• De-myth the 1% (and 70%) thresholds
26 May 2017 13
Main contents

14. Ch4 - AQ considerations
Future air quality situation is uncertain
• should you reduce background?
• what emission rates to apply?
Common pitfalls
• inter-annual variation
• receptor location
How to address effects of other schemes?
• in combination/cumulative
• The Ashdown Forest Case
26 May 2017 14

15. The gap to be bridged…
26 May 2017 15
A road viaduct is proposed over a bog habitat

16. DMRB assessment
Distance from
SAR
Centreline
(m)
Total Nitrogen
Deposition
Rate (kg
N/Ha/year)
Road
Contribution
(kg N/Ha/year)
Road
Contribution as
% of Total
Nitrogen
Deposition Rate
Critical
Load
Critical Load
Exceedance
Range
6 10.64 0.14 1.3% 5 - 10 5.64 to 0.64
10 10.62 0.12 1.1% 5 – 10 5.62 to 0.62
20 10.59 0.09 0.8% 5 – 10 5.59 to 0.59
30 10.57 0.07 0.7% 5 – 10 5.57 to 0.57
40 10.56 0.06 0.6% 5 – 10 5.56 to 0.56
50 10.54 0.04 0.4% 5 – 10 5.54 to 0.54
60 10.53 0.03 0.3% 5 – 10 5.53 to 0.53
70 10.53 0.03 0.3% 5 – 10 5.53 to 0.53
80 10.52 0.02 0.2% 5 – 10 5.52 to 0.52
90 10.52 0.02 0.2% 5 – 10 5.52 to 0.52
100 10.51 0.01 0.1% 5 - 10 5.51 to 0.51
26 May 2017 16
Lots of numbers generated and criteria to chose from!

17. Selection of critical load
According to APIS website, modifying
factors should be considered when
selecting which part of the critical load
range (5 to 10 kg N/ha/yr) should apply.
In this case, the bog is:
• in favourable condition,
• with a high water table,
• a rainfall range of 759 to 1285 mm, so
• a critical load of 9 kg N/ha/yr can be
applied.
26 May 2017 17
Getting bogged down…

18. Chapters 5 and 6
Determine ecological effects and mitigation
26 May 2017 18
Phil Davidson

19. Ch 5- Ecology Assessment
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Purpose
• Advice to support the ecological assessment
• A framework that can be understood by both
ecologists and air quality specialists
• Helpful examples and references

20. Ch 5 – Ecology Assessment
26 May 2017 20
Main Contents
• Sets out a series of recommended steps for
assessing a potentially significant air quality impact
• Identifies factors that may increase or decrease the
ecological effects of an air quality exceedance
• Provides advice on consultation
• Refers to relevant literature and project examples

21. 26 May 2017 21
Assessment steps

22. Ch 5 – Ecology Assessment
26 May 2017 22
Opportunities and Pitfalls
• One size doesn’t fit all – but an opportunity to help
guide
• Inherent complexities in underlying science –
translate into a practical approach
• Proportionality and the precautionary approach
• Small increments and cumulative effects
• Different approaches by different regulators

23. Ch 6 – Mitigation
26 May 2017 23
Purpose
• Set out possible techniques with examples
• Consider the mitigation hierarchy
• Identify interactions with EcIA and HRA

24. Ch 6 – Mitigation
26 May 2017 24
Approach Taken
• Mitigation Hierarchy should be followed
• Avoidance/Prevention
• Mitigation
• Compensation / Off-setting
(where appropriate)
• Consideration of monitoring

25. Ch 6 – Mitigation
26 May 2017 25

26. Members consultation
Thank you for listening!
26 May 2017 26
Now for some questions…

27. Things to think about
Does it help you understand differences in
various assessment types?
Do you feel more informed about the other
discipline’s needs and assessment?
Does it clearly describe the steps you will
need to take to calculate / interpret results?
Does it increase your confidence in dealing
with air quality outputs?
Would it benefit from more information on
dose-response relationships?
26 May 2017 27
When reading the draft document:

28. You can contribute!
Do you have any good examples of
• collaboration between disciplines?
• papers on dose-response?
• mitigation of impacts?
• monitoring of effects?
• practical examples?
26 May 2017 28

29. 26 May 2017 29
Questions / Discussion