EIR - ULEZ 1 Year report data [Apr 2025]

Your request 

1. Air Quality Data – All monitoring data, including NO₂, PM₂.₅, and PM₁₀ readings before and after ULEZ implementation.
2. Traffic Flow Data – Any studies or datasets analysing vehicle numbers, types, and emissions levels in ULEZ areas.
3. Public Health Impact Data – Studies or datasets on respiratory and cardiovascular health impacts attributed to ULEZ changes.
4. Economic and Business Impact Data – Any economic assessments related to the financial implications for residents and businesses.
5. Compliance and Enforcement Data – Information on vehicle compliance rates, penalty charge notices, and revenue generated.
6. Modelling and Projections – Any predictive models or forecasts related to ULEZ effectiveness.
7. Public and Stakeholder Consultation Data – Summaries or full datasets of public and business feedback regarding ULEZ changes. If any of these datasets are exempt from disclosure, I request a detailed explanation of the grounds for exemption, as well as any redacted versions where possible.

If the information is available in electronic format, I would appreciate it being provided in a machine-readable format such as CSV or Excel

Our response

1. The London-wide ULEZ One Year Report provides an extensive analysis of the impacts of the first year of the London-wide ULEZ and clearly notes the limitations of the data, as well as providing detailed summary tables of the data for readers. The report, as well as the supporting data, is available on the GLA website via the following link, which provides the requested information: London-wide Ultra Low Emission Zone One Year Report | London City Hall. We have published the air quality data in the report, in line with best practice, so that people can review our analysis. The air quality concentration data is freely available online. The Supplementary Data Sheet 2 - Concentrations Excel document (available at the above link) directs users to the sources where we have downloaded the data. As we used hourly data from 440 nitrogen dioxide (NO2) monitoring stations and 197 fine particulate matter (PM2.5) stations over a period of more than ten years, it would not be feasible to provide this data as raw downloaded data due to the size of the files required. However, we have provided all of the information to enable anyone to source the data underlying our results.
2. TfL used data from over 200 Automatic Traffic Count (ATC) sites, that provide traffic volumes at representative sites, often on key roads across London, to monitor changes in traffic flows. These sites provide total traffic flows for all vehicles for each hour of the day. This data is not held by the GLA. Additional data was used from the Department for Transport, which can be found here: https://roadtraffic.dft.gov.uk/downloads. Additionally, the annual vehicle fleet compositions are based on analysis of daily captures from the available TfL camera network, this data is also not held by the GLA. The methodology for calculating emissions is detailed on page 45, and more detail in Appendix 2 of the London-wide Ultra Low Emission Zone One Year Report | London City Hall
3. The London-wide ULEZ One Year Report does not aim to quantify the health impacts of the ULEZ. We do not hold this data.
4. Please see “Footfall and economic activity” section within the London-wide ULEZ One Year Report.
5. Compliance data has been provided in “Vehicle Compliance” section and Appendix 1 of the London-wide ULEZ One Year Report. You can find all data on PCNs in TfL’s “Finance, operations & performance” quarterly factsheets, which can be found here: Ultra Low Emission Zone - Transport for London. Regarding revenue, TfL publishes details of income from all road user charging schemes, including the ULEZ, in its Annual Report and Statement of Accounts, which is available on the TfL website at: Annual Report - Transport for London. Any net revenue raised by the ULEZ must be reinvested into running and improving London’s transport network.
6. Prior to the London-wide expansion of the ULEZ, TfL undertook an extensive consultation which included an Integrated Impact Assessment, detailing predicted impacts of the ULEZ. This can be found here: Key Documents | Improving air quality and Londoners' health, tackling climate change and reducing congestion | Have Your Say Transport for London
7. As above, TfL undertook an extensive consultation prior to the London-wide ULEZ expansion. All documents pertaining to this can be found here: Key Documents | Improving air quality and Londoners' health, tackling climate change and reducing congestion | Have Your Say Transport for London.

• TfL is the Mayor's transport authority and is responsible for implementing the Mayor's Transport Strategy, and for the design, procurement, delivery and operational running of road user charging schemes such as the ULEZ. You may wish to send a further request to TfL at [email protected].