Oxford’s air quality has continued to improve, with the city meeting its local air pollution target for the first time, new data from Oxford City Council has found.
Latest data from Oxford City Council has found that in 2025, all sites of relevant public exposure were below Oxford’s local annual mean target for nitrogen dioxide (NO₂) of 30 micrograms per cubic metre of air (µg/m³).
This is the first time every site where people are likely to be regularly exposed to air pollution has measured below Oxford’s local NO₂ target.
The milestone means the city has achieved the target set out in Oxford’s Air Quality Action Plan 2021–2025, which committed the Council and its partners to reducing annual mean NO₂ levels to 30 µg/m³ across the city by the end of 2025.
St Clements, historically one of Oxford’s highest NO₂ locations and the last remaining site of relevant public exposure above the local target, saw annual mean NO₂ levels fall from 34 µg/m³ in 2024 to 28 µg/m³ in 2025. This is a reduction of around 18%.
Across the city, average NO₂ levels fell by 5.6% in 2025, from 18 µg/m³ in 2024 to 17 µg/m³. Over the last decade, average NO₂ levels in Oxford have fallen by 53%.
Despite this progress, there continues to be no safe level of air pollution.
The data follows the publication of Oxford City Council’s latest Air Quality Annual Status Report for 2025, which examines air pollution levels across 118 monitoring locations in the city from January 2025 to December 2025.
Monitoring air pollution
Nitrogen dioxide (NO₂) is measured in micrograms in each cubic metre of air (µg/m³), with the legal annual mean limit set by Government at 40 µg/m³.
In Oxford, there are two annual mean targets for NO₂ air pollution:
- National legal limit: the annual mean concentration of NO₂must not exceed 40 µg/m³
- Oxford’s local annual mean target: the annual mean concentration of NO₂ should not exceed 30 µg/m³ at sites of relevant public exposure by the end of 2025
Oxford City Council has a statutory duty to report on air quality within the city and gathers data from each monitoring station, following detailed technical guidance from Defra.
|
Pollutant |
World Health Organisation (WHO) recommended annual mean |
UK Legal annual mean limit value |
Oxford’s local annual mean target (commitment to be achieved across the city by 2025) |
|
PM2.5 |
5 μg/m³ |
10 μg/m³ |
Not applicable |
|
NO2 |
10 μg/m³ |
40 μg/m³ |
30 μg/m³ |
Report highlights
Some of the highlights of the latest report are:
- Oxford has met its 2025 local annual mean NO₂ target of 30 µg/m³ at all sites considered to be of relevant public exposure
- For the first time, every site of relevant public exposure in Oxford measured below 30 µg/m³
- NO₂wasmonitored at 118 sites across the city in 2025
- None of the 118 sites were found to be in breach of the UK’s legal annual mean limit of 40 µg/m³ for NO₂
- None of the 118 sites are likely to have breached the hourly meanobjectivefor NO₂. This is the ninth consecutive year this has been achieved
- Citywide, NO₂ levels decreased by 5.6% on average in 2025
- On high bus traffic routes, including High Street and St Aldates, NO₂levels decreased by an average of 14% compared to 2024
- 2025 was the first full year in which Oxford saw the air quality benefits of the introduction of 159 electric buses
- Over the last decade, average NO₂levels in Oxford have reduced by 53%, with a 26% reduction since 2021, when the city launched itsprevious Air Quality Action Plan
Three sites were above Oxford’s local annual mean NO₂ target of 30 µg/m³. These were Headington Hill, which measured 32 µg/m³ and two sites on Oxford’s ring road (32 µg/m³ and 33 µg/m³).
These locations are not considered sites of relevant public exposure under Local Air Quality Management guidance, as they are places where people are not expected to be regularly present for long enough for the annual mean target to apply. They are monitored to help understand the potential impact of future transport interventions, including traffic filters.
Impact of electric buses
The latest report highlights the positive impact of Oxford’s electric bus programme on air pollution levels in the city.
In 2025, NO₂ levels on high bus traffic routes, including High Street and St Aldates, fell by an average of 14% compared to 2024.
This is largely due to the introduction of 159 electric buses into Oxford’s bus fleet through the Zero Emission Bus Regional Areas scheme, known as ZEBRA.
Electric buses now account for 69% of total bus mileage in the city. The rapid transition away from diesel buses on core routes has helped reduce tailpipe emissions, particularly in the city centre and along key routes where bus movements are frequent and public exposure is high.
Zero Emission Zone
The Zero Emission Zone pilot in Oxford city centre has also supported improvements in air quality.
Launched by Oxfordshire County Council and Oxford City Council in February 2022, the ZEZ pilot encourages the use of zero emission vehicles and discourages the most polluting vehicles from entering parts of the city centre.
The latest report highlights the role of the ZEZ in helping to reduce NO₂ concentrations in locations that have historically experienced higher levels of air pollution in the city centre.
The ZEZ has also helped encourage residents, businesses and visitors to consider cleaner ways to travel and move around Oxford.
Temporary congestion charge and traffic filters
Oxford City Council’s latest Air Quality Annual Status Report identifies the delivery of Oxfordshire County Council's trial traffic filters as one of the priorities for the next reporting year.
As the congestion charge was only in place for the final two months of the 2025 reporting period, there is not yet enough data to assess its impact on air quality. The council’s air quality monitoring will continue to monitor the effect of the congestion charge and subsequent traffic filters trial over time.
Particulate pollution
PM10 and PM2.5 were both monitored by automatic continuous monitors at AURN St Ebbes and Oxford High Street in 2025.
The PM10 annual means recorded at these sites were 10 µg/m³ and 17 µg/m³ respectively. These values are both below the current UK legal annual mean limit for PM10 of 40 µg/m³.
The PM2.5 annual means recorded at these sites were 7 µg/m³ and 9 µg/m³ respectively. These values are below the current UK legal annual mean limit for PM2.5 of 10 µg/m³, but remain above the World Health Organisation recommended annual mean of 5 µg/m³.
The report also notes that ozone levels measured at AURN St Ebbes exceeded legal air quality objectives during 22 days in 2025. Unlike NO₂, ozone is not emitted directly, but is formed through chemical reactions in sunlight and can be influenced by weather and wider regional air pollution.
Next steps
The Council’s report will be submitted to the Government to be ratified and approved.
The Council publishes annual air quality monitoring reports for the city every summer, these are all freely available to read on its website.
In February 2026, Oxford City Council adopted a new Air Quality Action Plan for 2026–2030, setting a new local annual mean NO₂ target of 20 µg/m³ to be achieved across the city by 2030.
This new “20 by 30” target goes beyond the UK’s legal limit of 40 µg/m³ and reflects the Council’s commitment to driving air pollution down further to protect residents’ health.
Comment
“This is a major milestone for Oxford and a really important moment for everyone who has worked so hard over many years to improve air quality in our city.
For the first time, every site of relevant public exposure is below Oxford’s local NO₂ target of 30 µg/m³. That means we have achieved the ambitious target we set ourselves in our Air Quality Action Plan, and it shows that sustained local action can make a measurable difference.
The introduction of electric buses has played a particularly important role, especially in the city centre and on busy bus routes, and we are now seeing the benefits of that investment in cleaner air. But we cannot and will not stop here. There is no safe level of air pollution, and we know it continues to harm people’s health, particularly children, older people and those with existing heart and lung conditions.
That’s why our new Air Quality Action Plan goes even further, with a new target to reduce annual mean NO₂ levels to 20 µg/m³ across the city by 2030. Cleaner air is better for everyone, and we remain committed to working with our partners and communities to make Oxford a healthier city.”
Councillor Anna Railton, Deputy Leader and Cabinet Member for Planning and a Zero Carbon Oxford
