Oxford has recorded significant progress in reducing air pollution, with much of this progress attributable to the city’s growing fleet of electric buses.
In 2024, average NO₂ levels across the city fell by 10%, with even larger reductions observed in areas of high bus traffic. On High Street and St Aldate’s, for example, NO₂ levels dropped by up to 24%.
These improvements are largely attributed to the introduction of 159 electric buses funded through the government’s ZEBRA scheme, which began operating in January 2024 and now account for nearly 70% of bus mileage in Oxford.
Encouragingly, Oxford met all UK legal limits for NO₂ in areas where people are regularly exposed to air pollution. Only one location – Headington Hill – exceeded the national limit, but it is in an area with limited public exposure and showed a 19% reduction in NO₂ levels compared to 2023. Only four sites exceeded Oxford’s stricter local NO₂ target of 30 µg/m³, with three located in areas of low pedestrian activity.
Over the past decade, average NO₂ levels in Oxford have dropped by 52%, reflecting the city’s consistent efforts to improve air quality. An updated source apportionment study published earlier this year shows that transport remains the largest contributor to NOx, although emissions from buses have declined by 28% compared to the previous assessment.
The Zero Emission Zone (ZEZ) pilot, launched in 2022, continues to show positive results. NO₂ levels within the ZEZ remain well below both national and local targets, especially in pedestrianised areas (e.g. Cornmarket and New Inn Hall Street). Streets shared by pedestrians, buses, and taxis (e.g. Queen Street and New Road) also saw marked reductions in pollution.
Low Traffic Neighbourhoods (LTNs) across Oxford similarly demonstrated year-on-year improvements in NO₂ levels, with no sites breaching the UK legal limits.
On the LTNs’ boundary roads, most locations recorded small reductions of 1–2 μg/m³, but there were some notable success stories – particularly on streets with high bus traffic. St Clements, once Oxford’s most polluted street, saw levels drop by between 3-5µg/m³.
Similarly, In Between Towns Road saw a fall of 5 μg/m³.
Within the city’s LTNS the average decrease in NO2 levels ranged from 1 to 2 μg/m3. None of the NO2 levels measured both inside and on the boundary roads of Oxford’s LTNS was above the UK legal limit value.
The report also confirms that particulate pollution remains well within legal limits. Levels of PM2.5 and PM10 at monitored sites were not only below UK thresholds but also approaching the stricter World Health Organization recommendations, highlighting Oxford’s steady progress toward safer air for all.
Cllr Anna Railton, Cabinet Member for a Zero Carbon Oxford, said: ‘It is great news that air pollution levels are continuing to fall across all areas of the city, that Oxford is are legally compliant in all locations of public exposure, and that we are close to reaching our localised air pollution target. However, it is important to remember that there is ultimately no safe level of air pollution – it always causes us harm.’
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