This internal operational Guidance Note describes how Natural England advises competent authorities and others on the assessment of plans and projects (as required by the Conservation of Habitats and Species Regulations 2017 (‘the Habitats Regulations’) likely to generate road traffic emissions to air which are capable of affecting European Sites. It has been published for information to help competent authorities to better understand Natural England’s own approach when applying the Habitats Regulations to these matters in its role as statutory adviser.
June 2026 note: Please be aware that Natural England’s current standing advice on air pollution assessment is held on gov.uk Air pollution and development: advice for local authorities – GOV.UK. Where this document differs, the standing advice must take priority. For Nationally Significant Infrastructure Projects and Local Plans, standard advice or bespoke advice will be provided which will reflect the principles of the standing advice.
The standing advice reflects changes in Natural England’s approach to assessment, responding to emerging evidence since publication of NEA001.
Key areas of difference are:
- The standing advice applies to all sectors – not just road traffic
- The standing advice applies to all statutory protected sites – not just Habitats sites
- Ammonia emissions from road sources must be assessed, in addition to NOx and nitrogen deposition
- The approach to screening emissions from road traffic is clarified, reflecting that the proxy 1000AADT threshold is not protective of all sites for all pollutants
- Use of Decision Making Thresholds to undertake an ‘in-combination assessment in advance’ at screening or assessment stage is outlined, to streamline assessment for developments with a very small impact at a protected site
- A streamlined approach to assessment for agricultural applications resulting in emissions reduction is outlined
This document has not been fully withdrawn as it still contains technical information not held in the standing advice. However, it will be fully updated in due course to reflect and support the standing advice.