There have been several High Court judgements that have considered the impacts of road traffic NOx emissions on nitrogen deposition at Ashdown Forest in Sussex; a special protection area designated under the Habitats Directive. This presentation reviews the background to Wealden District Council’s policies and discusses the application of Highway England’s DMRB scoping criterion of 1,000 AADT and the Environment Agency’s criterion of 1% of the critical load when assessing the ‘in combination’ effects. It provides insights into the approach suggested in the forthcoming guidance from CIEEM and IAQM. This document is due to be circulated to members for comment imminently.

1. Brook Cottage Consultants Ltd.: Experts in Air Quality Management
ASHDOWN FOREST:
IMPLICATIONS OF RECENT LEGAL JUDGEMENTS
Dr Claire Holman
Brook Cottage Consultants
University College London

2. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
Contents
• Ashdown Forest
• Wealden District Council’s Core Strategy
• Legal challenges
• Implications for Air Quality Practitioners
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3. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
Ashdown Forest
• A deer hunting forest in
Norman times
• Setting for the Winnie-the-
Pooh stories written by A.
A. Milne, who lived on the
northern edge of the forest
• Wealden District, East
Sussex
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4. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
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Wealden District Council East Sussex

5. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
Ashdown Forest
• Largest area with open public
access in South East England
(2,500 ha).
• One of the largest continuous
blocks of lowland heath in SE
England
• In High Weald AONB
• Conservators of Ashdown
Forest - responsible for the
management the Forest
• 2.5% of the UK's heathland
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Source: www.ashdownforest.org

6. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
SpecialArea of Conservation (SAC)
Ashdown Forest:
• Site of Special Scientific
Interest (SSSI)
• Special Protection Area
(SPA)
• SAC
o Northern Atlantic wet
heaths with Erica
tetralix
o European dry heaths
• One of the largest
continuous blocks of
lowland heath in SE
England
• SAC covers 2729 Ha
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7. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
Habitats Regulations
• Council Directive 92/43/EEC on the
conservation of natural habitats and
of wild fauna and flora (“the Habitats
Directive”)
• The Conservation of Habitats and
Species Regulations 2010 (“the
Habits Regulations”)
Reg 61.
(1) A competent authority, before
deciding to undertake, or give any
consent, permission or other
authorisation for, a plan or project
which
(a) is likely to have a significant
effect on a European site
(either alone or in
combination with other
plans or projects), and
(b) is not directly connected with
or necessary to the
management of that site,
must make an appropriate
assessment of the implications
for that site in view of that site’s
conservation objectives.
Appropriate assessment is not
defined in the Directive or
Regulation
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8. Brook Cottage Consultants Ltd.: Experts in Air Quality Management
Wealden District Council Core Strategy – HRA 2011
Conclusion :
“No adverse effects on the ecological
integrity of any European site as a result of
the Wealden District Core Strategy in
relation atmospheric pollution at Ashdown
Forest SAC”
No ‘in-combination assessment’
undertaken because nearby local
authorities’ plans were at a much earlier
stage.
Core Strategy results in up to 950
vehicles
Less than DMRB scoping criterion
(1,000 vehicles per day)
No more detailed analysis undertaken
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DMRB = Highways England’s Design Manual for Roads and Bridges

9. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
Core Strategy Inspector’s Report
“… I am satisfied that the DMRB methodology is the
correct approach to a scoping assessment of air quality
and that, as concluded in the HRA, the scale and
distribution of development proposed in the CS is
acceptable in this regard.”
“...Based on the DMRB results, one section of the A26
would have an additional AADT of 950, indicating very little
headroom for development beyond that proposed without
further assessment to determine whether there would be a
likely significant effect on the Ashdown Forest SAC.
Core Strategy Adopted in Feb 2013
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AADT = annual average daily traffic

10. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
Wealden District Council Legal Challenges
WDC Local Plan
• Ashdown Forest Economic Development LLP v SSCLG, Wealden District
Council & South Downs National Park Authority [2014] EWHC 406
(Admin)
• Ashdown Forest Economic Development LLP v Wealden District Council
& South Downs National Park Authority [2015] EWCA Civ 681
Steel Cross (103 homes in Crowborough)
• Wealden District Council v SoSCLG & Knight Developments Limited
[2016] EWHC 247 (Admin)
• SoSCLG & Knight Developments Limited v Wealden District Council
[2017] EWCA Civ 39
LDC / SDNPA Local Plan
• Wealden District Council v SoSCLG, Lewes District Council, South
Downs National Park Authority and Natural England [2017] EWHC 351
(Admin)
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11. Brook Cottage Consultants Ltd.: Experts in Air Quality Management
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12. Brook Cottage Consultants Ltd.: Experts in Air Quality Management
WDC’s Position March 2017
In practical terms this means
demonstrating that the development of
a site will provide no more
vehicle emissions than currently along
the affected roads in the SAC.
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13. Brook Cottage Consultants Ltd.: Experts in Air Quality Management
Wealden’s Position June 2017
...the Council will continue to assess the
impacts of development on the Ashdown
Forest Special Area of Conservation
(SAC) ... but until the necessary
compensation/mitigation measures are
in place, developments throughout the
District can only proceed where they
can prove that they will not damage the
SAC any further.
...In the interim, we are aware we are not
in a position to determine some live
planning applications within the District
which have potential to adversely affect
the SAC as a result of Air Quality impacts.
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14. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
Wealden’s Position September 2017
If you have such an application
awaiting decision, I am seeking
your cooperation through written
confirmation, either by e-mail or
letter, to extend the period of
determination for your application
until Friday 19th January 2018...
following this time, I would hope
to be in a position to offer some
significant updates upon the
implications of the Habitats
Regulations for your current
application(s).
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15. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
Wealden District Council v SoSCLG, Lewes District Council
(LDC), South Downs National ParkAuthority (SNNPA) and
Natural England
Mr Justice Jay
“The DMRB is not wholly clear as
to the extent to which cumulative
impacts need to be considered,
and at which stage”
DMRB
3.12 Obtain traffic data for the
Do-Minimum and
Do-Something scenarios for
the years to be assessed.
Identify which roads are
likely to be affected by the
proposals. Affected roads
are those that meet any of
the following criteria:
• ...; or
• daily traffic flows will
change by 1,000 AADT
or more; or... 16

16. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
“Simple Addition”
• Natural England advised LA
• NE expert view was that “1000 AADT was a sufficiently protection
threshold to cover in-combination effect”
A26
Wealden (950) + Lewis (190) = 1140 i.e. > 1000 AADT.
Mr Justice Jay
“It was not apparent why Natural England was advising that a
cumulative assessment did not require an aggregation of two figures”
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17. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
Natural England
• 1,000 AADT = 1% of critical load
• A “reasonable guideline threshold for determining likely
significant effects”
• It has been used for “almost 10 years as an air quality
assessment tool, having been first developed in 2004”
• “1% threshold was agreed by another expert body, the Air
Quality Technical Advisory Group (“AQTAG”)”
• 1% criterion used by Environment Agency (+ equivalent
developed regulators)
AQTAG = formed in 2000 to provide technical guidance on the
assessment of air emissions from IPC/IPPC processes
Natural England is a member 18

18. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
Implications – Draft Guidance from CIEEM/IAQM
Different approaches needed for traffic and point source
impacts.
Isolated point sources
• For installations other than intensive pig and poultry farms, AQTAG
is confident that a process contribution (PC, as predicted by H1 or
a detailed dispersion model) < 1% of the relevant critical level or
load can be considered inconsequential and does not need to be
included in an in-combination assessment
• “Experience of permitting allows us to be confident that it is unlikely
that a substantial number of plans or projects will occur in the same
area at the same time, such that their in-combination impact would
give rise to concern at the appropriate assessment stage. If such a
situation was to arise then the assessment could be determined on
a case-specific basis.” AQTAG
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19. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
Implications – Draft Guidance from CIEEM/IAQM
Isolated point sources (cont’d)
• Where the regulator’s criterion is met and there is unlikely to be an
in-combination effect (e.g. road transport or agriculture), screening
out the need for further assessment using EA1 criteria will generally
be appropriate
• Defining an ‘isolated point source’ precisely is not possible, and it is
a matter of judgement. If in doubt assume that there may be an in-
combination effect.
Non isolated point source
• In combination impacts needs to be taken into account during
screening if a point source plume overlaps with a road within 200m
of a European designated site and/or one or more point source
plumes overlaps
• Regulators do not always consider the traffic impacts 20

20. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
Draft CIEEM/IAQM Guidance
• A change of >1% does not mean that a significant effect (or adverse
effect on integrity) will occur; it simply means that the effect requires
further consideration.
• Ecologists need to consider the potential effects
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21. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
Implications – Draft Guidance from CIEEM/IAQM
Traffic
• The DMRB thresholds apply to Highway Agency1 road schemes
• In the absence of any other thresholds it has been widely applied to
projects and local development plans
• Following the High Court ruling a project or plan meeting the 1,000 AADT
criterion alone is not sufficient to screen out the need to assess the in-
combination potential impact
• More likely to be in-combination impacts for traffic than large point
sources.
• Many projects and plans can increase traffic on the same road link.
• In general it will not be possible to screen out the need for considering
the in-combination effects (there will be some exceptions e.g. where a
new road is planning)
1 and the devolved administrations
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22. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
Implications – Draft Guidance from CIEEM/IAQM
Local plans
• If when all relevant plans and
projects have been considered
the 1,000 AADT criterion is met,
the need for further assessment
can be screened out
• Judge ruled that the 1,000
AADT threshold cannot be
applied (at least not rigidly) to
growth arising from a single
district.
• But how far do we need to go?
• Consider plans where LA
boundary is 30 km away?
• Or just use TEMPRO?
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23. Brook Cottage Consultants Ltd.: Experts in Air Quality ManagementBrook Cottage Consultants Ltd.: Experts in Air Quality Management
Conclusions
• In-combination impacts will now be more difficult to screen
out
• Natural England is reconsidering its advice
• Highways England has been sent a copy of the
judgement
• Expect new guidance from Natural England in the coming
months.
• Draft guidance from CIEEM/IAQM due out imminently for
member comment.
• It is not for the air quality practitioner to assess the
ecological effect – this is the ecologist’s job.
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