Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, which (a) cities, (b) zones and (c) agglomerations in England exceeded the nitrogen dioxide annual mean limit value in 2023.

Defra uses a combination of national-scale modelling and on the ground monitoring to assess nitrogen dioxide (NO₂) concentrations in England each year. Evidence shows that NO₂ concentrations have reduced substantially in recent years, however a reporting zone is still considered to be exceeding the NO₂ limit value if a single location remains above the limit value. The cities, agglomeration and non-agglomeration zones exceeding the NO₂ limit value in 2023, and the predictions of when they will become compliant with the limit value, are based on data from Defra’s national modelling and monitoring networks, and additional local monitoring data gathered by cities and towns in England and held by the Joint Air Quality Unit.

13 cities in England exceeded the annual mean limit value for NO₂ in 2023. These were:

15 out of 31 reporting zones in England were non-compliant with the annual mean NO₂ limit value in 2023. This included 2 of the 8 non-agglomeration zones (South East and Eastern) and 13 of the 23 agglomeration zones. The 13 non-compliant agglomeration zones were:

Predicting when locations that are currently exceeding will comply with the limit value is inherently uncertain. We don’t hold up-to-date detailed modelled projections to predict the impact of all current policies on future NO₂ concentrations, however current indicative estimates suggest the majority of locations will become compliant with the limit value within the next four years. By 2029, we estimate all zones will be compliant except Bristol Urban Area, Sheffield Urban Area, The Potteries, West Midlands Urban Area and Tyneside. These correspond to Bristol, Sheffield, Stoke-on-Trent and Birmingham, all of which we estimate will become compliant by 2032, and Newcastle-upon-Tyne. We expect Newcastle-upon-Tyne will be the last city to become compliant due to a localised hotspot. There is considerable uncertainty in current estimates for when this location will become compliant, but we estimate this will be by 2045, at the latest. As the road traffic fleet continues to transition to zero emission vehicles this date is likely to come forward.