Collection Annual data on NO2 concentrations for the motorway and trunk road network How effective we have been in reducing nitrogen dioxide levels at 5 key sites. Part of: Air pollution (Sub-topic) and Roads and the environment (Sub-topic) First published: 31 March 2020 Last updated: 16 December 2025 Reports 2023 to 2024 16 December 2025 Report 2022 to 2023 17 October 2024 Report 2020 to 2021 8 September 2022 Report 2018 to 2019 21 December 2021 Report 2017 to 2019 (interim data) 7 October 2019 Policy and strategy