Key information
Request reference number: MGLA200524-3855
Date of response:
Summary of request
Request:
I write to request information relating to the ULEZ expansion of August 23.
The updated information for London regarding clean air, air pollution since August 23 is overdue. I would like to see the stats, comparing the difference in air quality in the outer London boroughs before and since ULEZ extension.
Also I understand this information was available prior to the mayoral election, but was not to be published until after the election, why was this information delayed/ withheld? When will it be released?
I have seen charts on londonair.org.uk before and after extension, showing no difference to the air quality in the extended ULEZ zone, in which case why not cancel the extension zone?
Please find below the information we hold within the scope of your request.
A preliminary assessment of the impact of the London-wide Ultra Low Emission Zone (ULEZ) on measured nitrogen dioxide (NO2) and particulate matter 2.5 (PM2.5) pollutant concentrations will be included in the London-wide ULEZ Six Month Report, due to be published in the coming weeks.
This will be followed by the One Year Report once a longer-term comparative trend analysis is available. We expect to publish the One Year Report in early 2025. This is the same reporting schedule that was followed for the inner London ULEZ.
London has one of the most comprehensive air quality monitoring networks of any global city and air quality is constantly monitored at over 150 locations. These sites are operated and funded by the London boroughs, Transport for London (TfL) and Heathrow Airport.
All data from the reference air quality monitors in London are publicly available on either the London Air (https://www.londonair.org.uk/LondonAir/Default.aspx) or Air Quality England (https://www.airqualityengland.co.uk/) websites, depending on which data manager the borough subscribes to. These websites include the monitor locations and dates they have been running, as well as all the pollution concentration data, which can be freely downloaded.
It is important to note that the analysis of the impacts of ULEZ looks at more than just the monitored data downloaded from the above websites. In order to determine the impact of the scheme, it is important to predict a “no-ULEZ” scenario which allows us to see an estimated scenario in which the ULEZ was not implemented. This includes analysis such as isolating the changes in concentrations at the roadside from changes in background concentrations, which removes the impact of changes over time due to processes at the regional scale (such as meteorological conditions). Further detail on the previous methodology undertaken can be found in the Inner London ULEZ One Year Report.
As such, there is always a delay between the air quality data becoming available and the publication of an associated report, which is due to the time taken to undertake the detailed analysis of the data.