If your planning application needs an air quality assessment, one document decides how it is judged: the EPUK & IAQM guidance Land-Use Planning & Development Control: Planning for Air Quality. It is not statute, but it is the de facto national standard that consultants follow and local authorities expect — and understanding it tells you exactly what a planner will be looking for. This guide explains the EPUK/IAQM guidance in plain English and how it is applied in 2026.
What the EPUK/IAQM guidance is
The guidance is published jointly by Environmental Protection UK (EPUK) and the Institute of Air Quality Management (IAQM). It provides a consistent method for deciding whether a development needs an air quality assessment, how to carry one out, and — crucially — how to judge whether the resulting impact is significant. It sits underneath the NPPF and national Planning Practice Guidance on air quality, translating high-level policy into a workable, repeatable process.
Because it fills the gap between policy and practice, it is the reference point in the great majority of English planning air quality assessments, and it is regularly cited in local authority validation checklists and supplementary guidance. For the basics of when an assessment is triggered, see our explainer on what an air quality assessment is.
Step one: screening
The guidance starts with a screening step to decide whether a full assessment is even needed. Screening looks at whether a development will:
- introduce new sensitive receptors (homes, schools, care homes) into an area of existing poor air quality — for example near a busy road or within an Air Quality Management Area;
- generate additional traffic above indicative thresholds, changing pollutant concentrations at nearby receptors; or
- create significant dust or emissions during construction, such as demolition and earthworks.
If a development falls below the screening thresholds, a short air quality statement may be all that is required. If it exceeds them, a full assessment follows. Construction impacts are handled under the separate IAQM dust methodology — see our guide to construction dust assessments.
Step two: judging significance
The part of the guidance that matters most is how it decides whether an operational impact is significant. Rather than a single pass/fail line, it uses a matrix that combines two things: the magnitude of change in pollutant concentration at a receptor (as a percentage of the relevant air quality objective, or AQAL), and the absolute concentration at that receptor relative to the objective. The output is a descriptor:
| Impact descriptor | Typical planning reading |
|---|---|
| Negligible | No material air quality concern |
| Slight | Minor effect; usually acceptable, may need light mitigation |
| Moderate | Effect that needs justification and mitigation |
| Substantial | Significant effect; likely to weigh heavily against consent |
The professional then forms an overall judgement of significance across all affected receptors. This is why two schemes with similar traffic can be judged differently — a small percentage change matters far more where the background concentration is already close to the legal objective.
The pollutants that drive the assessment
The assessment focuses on the pollutants most relevant to health and planning: nitrogen dioxide (NO₂), fine particulate matter (PM2.5 and PM10) and, for emissions sources, oxides of nitrogen (NOx). Background concentrations come from Defra's mapped data and the technical guidance in LAQM.TG(22). Tightening PM2.5 targets under the Environment Act are steadily raising the bar — we cover this in our article on PM2.5 and the Environment Act targets.
Air quality neutral, exposure and mitigation
In London, the EPUK/IAQM approach works alongside London Plan Policy SI 1, which requires major development to be at least air quality neutral and, in some cases, air quality positive. Elsewhere, the guidance frames how new residents are protected from existing poor air quality (exposure) and what mitigation — from layout and ventilation strategy to low-emission measures — can bring an impact down to an acceptable level. If your site is within a designated area, see our guide to Air Quality Management Areas.
Is the guidance changing in 2026?
The core Planning for Air Quality guidance remains the current benchmark in 2026. The wider policy conversation is active — at the start of 2026 the Environmental Audit Committee opened an inquiry into air pollution in England, and the IAQM continues to update related guidance (for example on odour). But for planning air quality assessments today, the EPUK/IAQM method and LAQM.TG(22) remain what councils apply.
How Fortress Associates can help
Fortress Associates prepares automated air quality assessments for planning applications across every UK local authority. Our reports use live official datasets at the point of creation — Defra background maps, AQMA boundaries, monitoring data and DfT traffic counts — and follow the EPUK/IAQM planning criteria, IAQM dust guidance (v2.2, 2024) and Defra LAQM.TG(22). The report is free and ready in minutes. To get started, contact us or browse our full range of planning services.
Sources & further reading
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