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Guidance on Decision-making Thresholds for Air Pollution 2021

Abstract

Available here are two reports, a main report and a technical report, which together provide an evidentiary basis for decision-making thresholds (DMTs), to inform the assessment of air quality impacts on designated sites. In addition, underlying data is provided for the baseline used to develop DMT as well as an explanatory video. The DMT provides evidence on when it is acceptable for a plan or project to be exempt from a bespoke in combination assessment because the assessment has been made in advance through this evidence.

These reports were commissioned by JNCC on behalf of the Inter-agency Air Pollution Group and Defra (Department for Environment, Food and Rural Affairs). The work was peer reviewed by scientific advisers from the UK’s Air Quality Technical Advisory Group (AQTAG), Inter-Agency Air Pollution Group (IAPG) and legal advisers. The contractors made changes accordingly.

The Main Report provides decision-making criteria to inform the assessment of air quality impacts on designated conservation sites. The criteria are intended to be applied to individual sources to identify those for which a decision can be taken without the need for further assessment effort.

Readers wishing to scrutinise the underlying technical evidence basis for the approach set out in the Main Report are referred to the supporting Technical Report. The Technical Report describes the setting of decision-making criteria for air quality impacts to designated nature conservation sites. The criteria are intended to be applied to changes caused by individual plans and projects, to establish whether there is a need to consider air quality effects further, including in combination with other plans and projects.

Each of the CNCBs and Regulators within AQTAG and IAPG has considered DMTs in their specific contexts. Some have decided not to explicitly incorporate them into protocols at this time. This should not be interpreted as rejection of the scientific basis for DMTs but rather a reflection of operational variation and the different remits of each agency.

Currently DMTs are mentioned externally in:

These resources may not be fully accessible for all users. If you need copies in a different format, please contact Communications@jncc.gov.uk.

Resource type Publication

Topic category Environment

Reference date 2021·12·01

Citation
Chapman, C. & Kite, B. 2021. Guidance on Decision-Making Thresholds for Air Pollution. JNCC Report No. 696 (Main Report), JNCC, Peterborough, ISSN 0963-8091. Air Quality Consultants Ltd. 2021. Decision-Making Thresholds for Air Pollution. JNCC Report No. 696 (Technical Report), JNCC, Peterborough, ISSN 0963-8091.

Lineage
These reports have been commissioned by JNCC, on behalf of the Inter-agency Air Pollution Group and the Department for Environment, Food and Rural Affairs.

Responsible organisation
Communications, JNCC publisher

Limitations on public access No limitations

Use constraints Available under the Open Government Licence 3.0

Metadata date 2026·05·15

Metadata point of contact
Communications, JNCC

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