SmogRank / United Kingdom / England / London
London, month by month
London has a measured daily mean on 1,327 days since 1 January 2023. Its worst month was March 2025, at 68 US AQI (18.2 µg/m³), 680th of 2,862 cities on that month's world ranking. Its cleanest was August 2023, at 32 US AQI (5.7 µg/m³). 2025 averaged 53 US AQI (10.4 µg/m³), against 47 US AQI (8.4 µg/m³) in 2024.
Every month since 2023
The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales
Months without a mean, and why
2 months
| Month | Why |
|---|---|
| Mar 2023 | 11 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive. |
| Feb 2023 | 3 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
London's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| March 2025 | 6818.2 µg/m³ | 680thof 2,862 | Europe, March 2025 Germany, Poland and 25 more countries, March 2025and 1 more |
| February 2025 | 6315.7 µg/m³ | 834thof 2,633 | Europe, 14 February to 1 March 2025 Europe, 1 to 14 February 2025 |
| March 2026 | 6013.7 µg/m³ | 981stof 2,971 | Europe, 18 to 25 March 2026 Europe, 1 to 12 March 2026 |
| January 2025 | 5913.6 µg/m³ | 575thof 2,474 | Germany, France and 19 more countries, January 2025 Western Europe, January 2025 |
| November 2024 | 5913.5 µg/m³ | 482ndof 2,624 | Europe, November 2024 |
| April 2025 | 5812.6 µg/m³ | 696thof 2,951 | United Kingdom, Belgium and 2 more countries, April 2025 United Kingdom and France, April 2025 |
Monthly means over the days measured; finished months only. World rank: its place on that month's world ranking of every city with enough days. Each month opens that ranking.
London's worst days
| Day | US AQI | Episode |
|---|---|---|
| 10 Mar 2025 | 15764.5 µg/m³ | Germany, Poland and 25 more countries, March 2025 |
| 11 Jan 2025 | 12746.0 µg/m³ | Western Europe, January 2025 |
| 9 Mar 2025 | 11039.3 µg/m³ | Germany, Poland and 25 more countries, March 2025 |
| 26 Jan 2026 | 10838.5 µg/m³ | Europe, January and February 2026 |
| 5 Mar 2025 | 10336.5 µg/m³ | Germany, Poland and 25 more countries, March 2025 |
| 12 Jan 2025 | 10336.2 µg/m³ | Western Europe, January 2025 |
| 14 Feb 2023 | 10235.9 µg/m³ | Europe, 6 to 25 February 2023 |
| 5 Nov 2024 | 9935.1 µg/m³ | Europe, November 2024 |
| 24 Mar 2025 | 9934.9 µg/m³ | Europe, March 2025 |
| 23 Jan 2023 | 9934.8 µg/m³ | France, The Netherlands and United Kingdom, January 2023 |
Daily means, the highest since 1 Jan 2023; the WHO's daily guideline is 15 µg/m³. Each date opens that day's world ranking, and each episode the bad-air spell it was part of.
Use this history
SmogRank, PM2.5 monthly and daily means, London, United Kingdom, 1 Jan 2023 – 12 Oct 2026. Monitor data from London Air Quality Network and UK-AIR (Defra), via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/gb/london/history (accessed 13 Oct 2026).
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.
London now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-13 01:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver), no reuse terms published (why we use them).