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Clean Air Zones and Air Quality Assessments: what you need to know

Air Quality and Odour By Jenny Carrington, Associate, Air Quality – 25 January 2023

Low emission zone sign in front of a red bus


Jenny in a blue dress and acoustics feature background

Jenny Carrington

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Clean Air Zones (CAZ) and Low Emission Zones (LEZ) are areas where targeted action is being taken to improve air quality associated with vehicle emissions by introducing fees to discourage the most polluting vehicles from entering the zone.

To inform our Air Quality Assessments we always consider any CAZ or LEZ, existing or planned, and how this might change our recommendations for design mitigation, specifically including the proposed ventilation strategy. As this is constantly evolving, we need to remain informed on any proposed changes and consider how this would impact future schemes. Whether this will have a positive or adverse impact needs to be carefully considered based on the proposed development and its setting in relation to the zone boundary.

Since the first zone was introduced in Sweden in 1996, there are now over 250 LEZs across 15 European countries that are either planned or in operation. Zones already in operation have demonstrated good potential for improving ambient air quality by reducing nitrogen dioxide (NO2) concentrations. There is more limited potential for improving particulate matter (PM2.5) as these are also related to brake and tyre wear as well as tailpipe emissions.

Introduction of CAZs will deliver substantial health and economic benefits. Reductions in pollutant emissions will reduce associated impacts on premature death rates and other health outcomes, including low birth weight or preterm births, cardiorespiratory disease, lung and non-lung cancer, cognitive development and neurological disorders. The costs of dealing with illness related to air quality by the NHS between 2015 and 2035 is estimated to be £5.4 billion, with the wider economic cost to society estimated to be £20 billion/year. Further information of the economic benefits of CAZ schemes in the UK can be found on the Clean Air Fund website.

With the imminent introduction of a new zone for Tyneside this month, please see the latest information below.

  • Tyneside - Newcastle and Gateshead CAZ is due to start charging on 30th January 2023. This follows the implementation of other CAZs in England, such as Bath, Birmingham, Bradford, Brighton, Bristol, Portsmouth and York.
  • Sheffield CAZ is due to follow shortly after, with charging to commence on 27th February 2023.
  • Greater Manchester is still under consideration following the combined authority’s submission of an alternative proposal for a new investment led Clean Air Plan.
  • The London Ultra Low Emission Zone (ULEZ) currently covers all areas within the North and South Circular Roads and is due to expand in August 2023 to encompass all London Boroughs. Information on proposed charging rates can be found on the TFL website.
  • Scotland has introduced LEZ in Aberdeen, Dundee, Edinburgh and Glasgow in May 2022. Enforcement of fees is to be implemented in June 2023 in Glasgow and Spring/Summer 2024 in Aberdeen, Dundee and Edinburgh. Further information can be found on the Low Emission Zone Scotland website.

Further information on CAZs such as applicable fees can be found on the website.

Please note that the charging fees and the vehicles affected differ for each zone and are usually based on the age/Euro class of the vehicle. Take a look at the gov website on the links above to check your vehicle. To see how your vehicle performs or to inform purchase of a new vehicle, real world emission testing data is available at Air Index.

It is hard to fully predict what future impact these zones will have on air quality as things are advancing and evolving at such a high speed. For the latest information on how a CAZ or LEZ can affect your building or development please reach out to our air quality team.