Fine particles (PM2.5) averaged 8.0 µg/m³ at urban background sites in the UK in 2025, and nitrogen dioxide 20.4 µg/m³ at roadside sites in 2025
Annual mean concentration, averaged across monitoring stations of each type, UK: fine particles (PM2.5) 2009 to 2025, nitrogen dioxide (NO2) 1990 to 2025. Micrograms per cubic metre (µg/m³).
Latest figures
| Series | Period | Value |
|---|---|---|
| PM2.5, urban background | 2025 | 8.0 µg/m³ |
| NO2, roadside | 2025 | 20.4 µg/m³ |
| PM2.5, roadside | 2025 | 8.6 µg/m³ |
| NO2, urban background | 2025 | 13.5 µg/m³ |
| NO2, rural background | 2025 | 5.0 µg/m³ |
Notes
- PM2.5 is particles in the air 2.5 micrometres across or smaller. Nitrogen dioxide is a gas produced mainly when fuel is burned, much of it by road vehicles.
- Urban background stations are in towns and cities but away from busy roads and other nearby sources of pollution, so they measure the air typical of where most people live and work. Roadside stations are beside busy roads, where readings are usually higher because of emissions from traffic. Rural background stations are in the countryside, away from towns and roads.
- Each year's figure is the average of the annual means at every station of that type with measurements for at least 75% of the year. Stations open and close, so the set of stations averaged changes from year to year: for PM2.5 at urban background sites, 36 stations in 2009 and 71 in 2025; for NO2 at roadside sites, 7 stations in 1997 and 60 in 2025.
- The World Health Organization publishes guideline levels for the annual mean of each pollutant. They aren't in Defra's tables, so they aren't shown here.
Sources
- Department for Environment, Food & Rural Affairs, Air quality statistics: Particulate Matter (PM2.5) tables
- Department for Environment, Food & Rural Affairs, Air quality statistics: Nitrogen Dioxide (NO2) tables
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