Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, pursuant to the Answer of 26 March 2025 to Question 39816 on Nitrogen Dioxide: Pollution Control, which road links within 10 miles of Heathrow Airport are expected to exceed the nitrogen dioxide limit value in each of the last five calendar years of their non-compliance period.

The most recent national compliance assessment for 2023 did not report any road links within 10 miles of Heathrow Airport to be in exceedance of the annual mean limit value for nitrogen dioxide.

Local monitoring as part of the Local Air Quality Management (LAQM) process shows a small number of measurements in 2023 above 40µg/m³ at sites within a 10-mile radius of Heathrow Airport. There were single measurement sites above 40µg/m³ in the London Boroughs of Brent (A404), Wandsworth (A3), Richmond (A205), Merton (A219) and Kensington & Chelsea (A3220), and three measurement sites in Ealing (A4020, A40 and A406). National Highways’ assessments also indicated concentrations above 40µg/m³ at four road links on the Strategic Road Network (SRN). These are in the London Boroughs of Hounslow (two road links on the M4), Hillingdon (M4), and Spelthorne (A316). Air quality assessments under LAQM are assessed differently to the national assessment as they are focused on targeting local pollution hotspots which may occur in locations that don’t meet the data quality requirements for the national assessment.