Environment

Fine particles (PM2.5)

Modelled yearly average of fine particles (PM2.5) in the air away from busy roads, for every 1 km square of the UK.

Published by: Defra
Level of detail: 1 km grid (map point level)
Published for: Map point
Covers: All four nations
Updates: Yearly
Data period: Not recorded for this layer. The dates below are when it was published and fetched.
Published: 9 October 2026
Fetched by Open Index: 15 October 2026
Licence: Open Government Licence 3.0

Where it covers

Open Index shows the figures as Defra publishes them, for the areas they were published for: map points.

Larger areas use the publisher’s own figures, never an average of smaller areas.

These are modelled yearly averages for each 1 km square, not measurements at any one address.
They describe background air, away from busy roads. Beside a main road, levels are usually a little higher.
Part of the fine particles in the air comes from natural sources and from other countries, so levels vary from year to year with the weather.
One colour step is at 5 µg/m³, the World Health Organization's 2021 guideline for a yearly average, and another at 10, its fourth interim target and England's legal target for 2040.
From 2025 Defra uses a new model (CMAQ-Urban). Earlier years came from a different model, so don't compare years square by square.
Squares on the coast are shown where they touch land. Open Index doesn't average squares into councils, because that would need to know how many people live in each square.

Fixed breaks, held for every period, so colours mean the same over time.

Department for Environment, Food & Rural Affairs

Credit line

Source: Defra, modelled background air pollution maps. Contains public sector information licensed under the Open Government Licence v3.0.

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