About air quality in Westminster
Westminster contains some of the most heavily-trafficked roads in the country, anchored by the AURN-flagship London Marylebone Road site — one of the longest-running roadside reference monitors in the UK. The principal NO₂ pressure runs along Marylebone Road / Euston Road, Park Lane, Victoria Embankment, and the Strand / Aldwych corridor. Westminster has the densest air-quality monitoring of any London borough, with five active reference background sites, so the borough-level verdict here is the most robust of any borough page.
PM₂.₅ across Westminster is dominated by regional inflows and is typically similar to the rest of Inner London. The borough’s weekday population — workers, visitors, and political institutions — makes Marylebone Road’s roadside record disproportionately important to the national air quality conversation.
Last reviewed: 2026-05-18