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Research and analysis

Air quality compliance results summary 2025

Published 9 October 2026

© Crown copyright 2026

This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gov.uk.

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This publication is available at https://www.gov.uk/government/publications/air-pollution-in-the-uk-2025/air-quality-compliance-results-summary-2025

The air pollutants covered in the Air Pollution in the UK report are:

  • nitrogen oxides (NOx) comprising NO and NO2
  • particulate matter as PM10 and PM2.5
  • ozone (O3)
  • sulphur dioxide (SO2)
  • carbon monoxide (CO)
  • benzene
  • metals: lead, cadmium, nickel, and the metalloid arsenic
  • benzo[a]pyrene

For the purposes of air quality monitoring and assessment of compliance with The Air Quality Standards Regulations (2010), the UK is divided into 43 zones. See the methods for 2025 Air Quality Standards Regulations (2010) compliance assessment.

This report provides an assessment of compliance for the above pollutants. Government also has obligations to monitor and report data tables for additional pollutants (but not report against legal levels). These are known as ‘monitoring obligation pollutants’.

The results and data tables are published on the air quality compliance assessment 2025: results and data tables.

Results summary

The 2025 compliance results are summarised below.

These results are based on a combination of measurements and data from a new, more advanced national model. Some of the differences between the previous 2024 compliance assessment and the results for 2025 are due to this change in modelling approach.

For this reason, caution should be exercised when comparing these results to previous assessments, as these results do not necessarily represent a real-world change in air quality.

Nitrogen oxides NOx (NO and NO2)

For NO2, there are 2 limit values:

  • the UK met the limit value for hourly mean nitrogen dioxide (NO2) in all 43 zones
  • 40 zones met the limit value for annual mean NO2, with 3 zones exceeding

All zones required to meet the critical level for annual NOx set for protection of vegetation did so.

Read the nitrogen oxides (NOx) compliance assessment 2025.

Particulate matter as PM10 and PM2.5

  For PM10, there are 2 limit values:

  • all zones met the limit value for daily mean concentration of PM10
  • all zones met the limit value for annual mean concentration of PM10

For PM2.5:

  • all zones met the limit value for annual mean concentration of PM2.5 particulate matter
  • the UK continues to meet its 2020 national exposure reduction target for PM2.5

Read the:

Ozone

For ozone, there are 2 target values and 2 long term objectives:

  • one zone out of 43 exceeded the target value for ozone set for the protection of human health
  • all zones met the ozone target value set for the protection of vegetation
  • all zones exceeded the more stringent long-term objective for ozone, set for the protection of human health
  • 32 zones out of 43 exceeded the more stringent long-term objective for ozone, set for the protection of vegetation

There were no measured exceedances of the ozone population information threshold of 180 µgm-3 in 2025

Read the ozone compliance assessment 2025.

Sulphur dioxide, carbon monoxide, lead, arsenic, cadmium

All zones met the limit values for:

  • sulphur dioxide
  • carbon monoxide
  • lead

All zones met the target values for:

  • arsenic
  • cadmium

Read the:

Benzene

One zone out of 43 exceeded the limit value for benzene.

Read the benzene compliance assessment 2025.

Benzo[a]pyrene

2025 was the second year in which all zones have been compliant with the target value for benzo[a]pyrene.

Read the benzo[a]pyrene compliance assessment 2025.

Nickel

Three zones out of 43 exceeded the target value for nickel.

Read the nickel compliance assessment 2025.

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