Summary

Question 1

1.   Summary

Accepted Answer

This summary provides a selection of the key information from the full publication, 鈥楢ir quality statistics鈥�. This publication contains statistics which help describe the trends in concentrations of five air pollutants using a variety of metrics for the period 1987 to 2025. Data comes from the Automatic Urban and Rural Network (AURN), the UK鈥檚 highest quality network of air quality monitoring stations. Monitoring data is available from the new Get Air Pollution Data Service, and from the UK-AIR website which also contains information about monitoring networks for other UK air pollutants.

The full publication is available here: Air quality statistics in the UK.

Information on the trends in concentrations of specific pollutants are available from the following links:

Air quality statistics in the UK, 1987 to 2025 鈥� Nitrogen dioxide

Air quality statistics in the UK, 1987 to 2025 鈥� Particulate matter (PM10 and PM2.5)

Air quality statistics in the UK, 1987 to 2025 鈥揬nOzone

Air quality statistics in the UK, 1987 to 2025 鈥� Days with 鈥楳oderate鈥橽nor higher air pollution (includes sulphur dioxide)

The data used in this publication can be found in the accompanying tables.

Modelling is also undertaken to assess air quality across the UK, which provides estimates of concentrations across the entirety of the UK. This publication does not include modelled data and only uses data from monitoring stations.

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Question 2

2. Contact

Accepted Answer

Enquiries to: AQIE.Correspondence@defra.gov.uk

Tel: 03459 33 55 77 (Defra enquiries)

Lead analyst: Barney Dawes

Production team: Yoo-An An, Leo Blackman, George Clark, Isabel Hessey, Vanessa Liberson, Alex Mouatt, Sarah Reeves, Neil Ward

Air Quality Statistics team,

Department for Environment, Food and Rural Affairs,

Seacole Building,

2 Marsham Street,

London

SW1P 4DF

Question 3

3. Nitrogen dioxide (NO2)

Accepted Answer

Urban background and roadside nitrogen dioxide (NO2) pollution has shown long-term improvement.
In 2025, annual mean concentrations of NO2 showed an increase of 3 per cent at urban background stations and a decrease of 1 per cent at roadside stations from 2024 levels.
In 2025, there were 0 days of 鈥榤oderate鈥� or higher NO2 pollution at urban stations. Rural stations show a trend in reduction in short-term 鈥榤oderate鈥� or higher NO2 pollution since 2018, while urban stations show a trend for reduction since 2007, mainly due to reductions in this measure at monitoring stations in London.
In 2025, as in previous years, NO2 pollution tended to peak in the rush hours and during weekdays, particularly for roadside stations. Concentrations at roadside stations in 2025 were 20 per cent greater during the working week compared to the weekend. This pattern of concentrations follows the daily and hourly trends in road traffic.

Question 4

4. Particulate matter (PM10/PM2.5)

Accepted Answer

Urban background and roadside particulate pollution (PM10 and PM2.5) has shown long-term improvement despite a period of relative stability between 2015 and 2019.
In 2025, annual mean concentrations of PM2.5 showed an increase of 12 per cent at urban background stations and an increase of 14 per cent for roadside stations compared to 2024.
In 2025, annual mean concentrations of PM10 showed an increase of 12 per cent for urban background stations and an increase of 8 per cent for roadside stations compared to 2024.
The number of hours of 鈥榤oderate鈥� or higher levels of particulate matter (PM10/PM2.5) pollution has reduced in the long term. In 2025, the number of hours of 鈥楳oderate鈥� or higher pollution increased from the lowest in the time series in 2024 for both PM2.5 urban background and roadside as well as for PM10 urban background and roadside.
In 2025, the highest concentrations of PM2.5 in urban areas tended to occur during the first four months of the year.
Residential combustion of wood and coal in stoves and open fires is a large contributor to emissions of particulate matter both in the UK and across Europe and is a large contributor towards elevated concentrations in winter months and during the evenings.
PM2.5 concentrations also tend to peak in spring, which can be associated with air arriving from continental Europe, composed of fine particles (PM2.5), with nitrate playing a particularly important role. This nitrate appears to be largely associated with ammonium, derived from ammonia emissions which form secondary particulates and become Fine Particulate Matter (PM2.5) in the UK.

Question 5

5. Ozone (O3)

Accepted Answer

Urban background concentrations of O3 have shown a long-term increase, partly due to reductions in other pollutants which limit ozone concentrations (for example NOx).
In 2025, urban background concentrations showed an increase of 3 per cent from 2024 reaching 68.3 碌g/m³ which is the highest value in the time series. Rural background ozone pollution has stayed mostly constant since 2016.
There were on average more hours of 鈥楳oderate鈥� or higher ozone pollution in 2025 compared with 2024 at both rural and urban background stations. The number of hours of 鈥楳oderate鈥� or higher ozone pollution at both station types has been generally high since 2018, with the exception of 2021.
Ozone pollution is linked to hot, sunny conditions and prolonged instances of such conditions during the summers in most years since 2018 likely contributed to the higher incidences of 鈥楳oderate鈥� or higher ozone pollution observed during these periods.
In 2025, concentrations of ozone at both urban and rural background stations built up over the first few months of 2025, peaking in May then decreasing throughout the summer and autumn months.

Question 6

6. Days with 鈥楳oderate鈥� or higher air pollution (includes sulphur dioxide in addition to the pollutants reported above)

Accepted Answer

Sulphur dioxide is only included when measuring the number of days when air pollution reaches 鈥榤oderate鈥� or higher levels, please see the 鈥楳oderate鈥� or higher chapter for more detail. This is because measurements of SO2 using UK monitors are not representative of air pollution across the whole UK area since SO2 monitors are strategically placed next to point sources such as factories. Concentrations of SO2 are very low across the UK, which reduces the requirement to monitor concentrations of this pollutant.
There were on average 12 days of 鈥楳oderate鈥� or higher pollution at urban pollution monitoring stations in 2025, up from 6 in 2024.
Since reaching the highest value in the time series in 2018, the number of days of 鈥楳oderate鈥� or higher air pollution at rural monitoring stations has remained comparatively high but shows no clear trend.
Since 2015 the mean number of days of 鈥楳oderate鈥� or higher pollution has been higher at rural stations than urban stations due to ozone pollution. There were on average more days of 鈥楳oderate鈥� or higher pollution at rural pollution monitoring stations in 2025 compared with 2024 (11 days in 2024, 19 days in 2025).
In 2025, as in previous years, ozone was responsible for a large proportion of the 鈥楳oderate鈥� or higher pollution days. An increase in ozone pollution in most years since 2018 was in part due to the prolonged hot and sunny conditions experienced in the UK in the summers of these years.