Nitrogen Dioxide: Pollution Control

(asked on 20th March 2025) - View Source

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.


Answered by
Emma Hardy Portrait
Emma Hardy
Parliamentary Under-Secretary (Department for Environment, Food and Rural Affairs)
This question was answered on 26th March 2025

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:

Birmingham

London

Reading

Bradford

Manchester

Sheffield

Bristol

Newcastle-upon-Tyne

Stoke-on-Trent

Coventry

Nottingham

Liverpool

Portsmouth

14 out of 31 reporting zones in England were non-compliant with the annual mean NO2 limit value in 2023. This included 1 of the 8 non-agglomeration zones (South East) and 13 of the 23 agglomeration zones. The 13 non-compliant agglomeration zones were:

Bristol Urban Area

Nottingham Urban Area

Tyneside

Coventry/Bedworth

Portsmouth Urban Area

West Midlands Urban Area

Greater London Urban Area

Reading/Wokingham Urban Area

West Yorkshire Urban Area

Greater Manchester Urban Area

Sheffield Urban Area

Liverpool Urban Area

The Potteries

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.

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