SmogRank / United Kingdom / England / Westbury
Westbury, month by month
Westbury has a measured daily mean on 281 days since 27 March 2025. Its worst month was March 2026, at 54 US AQI (10.5 µg/m³), 1,539th of 2,971 cities on that month's world ranking. Its cleanest was September 2026, at 16 US AQI (2.9 µg/m³).
Every month since 2025
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
14 months
| Month | Why |
|---|---|
| Oct 2026 | 6 of 12 days measured; a month needs 9. The others: 2 with no readings from the monitors, 4 with readings for part of the day (a day needs 18 hours). |
| Aug 2026 | 9 of 31 days measured; a month needs 22. The others: 21 with readings for part of the day (a day needs 18 hours), 1 with under 18 hours of readings or readings that failed our checks. |
| Jul 2026 | 5 of 31 days measured; a month needs 22. The others: 26 with readings for part of the day (a day needs 18 hours). |
| Jun 2026 | 3 of 30 days measured; a month needs 21. The others: 26 with readings for part of the day (a day needs 18 hours), 1 with under 18 hours of readings or readings that failed our checks. |
| May 2026 | 5 of 31 days measured; a month needs 22. The others: 23 with readings for part of the day (a day needs 18 hours), 3 with under 18 hours of readings or readings that failed our checks. |
| Apr 2026 | 2 of 30 days measured; a month needs 21. The others: 27 with readings for part of the day (a day needs 18 hours), 1 with under 18 hours of readings or readings that failed our checks. |
| Feb 2026 | 18 of 28 days measured; a month needs 20. The others: 8 with readings for part of the day (a day needs 18 hours), 2 with under 18 hours of readings or readings that failed our checks. |
| Dec 2025 | 19 of 31 days measured; a month needs 22. The others: 8 with readings for part of the day (a day needs 18 hours), 4 with under 18 hours of readings or readings that failed our checks. |
| Oct 2025 | 19 of 31 days measured; a month needs 22. The others: 9 with readings for part of the day (a day needs 18 hours), 3 with under 18 hours of readings or readings that failed our checks. |
| Jul 2025 | 20 of 31 days measured; a month needs 22. The others: 10 with readings for part of the day (a day needs 18 hours), 1 with under 18 hours of readings or readings that failed our checks. |
| Jun 2025 | 4 of 30 days measured; a month needs 21. The others: 22 with readings for part of the day (a day needs 18 hours), 4 with under 18 hours of readings or readings that failed our checks. |
| May 2025 | 5 of 31 days measured; a month needs 22. The others: 21 with readings for part of the day (a day needs 18 hours), 5 with under 18 hours of readings or readings that failed our checks. |
| Apr 2025 | 20 of 30 days measured; a month needs 21. The others: 8 with readings for part of the day (a day needs 18 hours), 2 with under 18 hours of readings or readings that failed our checks. |
| Mar 2025 | 5 of 31 days measured; a month needs 22. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Westbury's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| March 2026 | 5410.5 µg/m³ | 1,539thof 2,971 | Europe, 18 to 25 March 2026 Europe, 1 to 12 March 2026 |
| January 2026 | 386.8 µg/m³ | 1,874thof 2,617 | – |
| August 2025 | 274.9 µg/m³ | 2,712thof 2,901 | – |
| November 2025 | 274.8 µg/m³ | 2,447thof 2,715 | – |
| September 2025 | 183.2 µg/m³ | 3,044thof 3,104 | – |
| September 2026 | 162.9 µg/m³ | 2,942ndof 2,997 | – |
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.
Westbury's worst days
| Day | US AQI | Episode |
|---|---|---|
| 31 Dec 2025 | 9532.6 µg/m³ | – |
| 8 Mar 2026 | 9029.8 µg/m³ | Europe, 1 to 12 March 2026 |
| 9 Mar 2026 | 8728.5 µg/m³ | Europe, 1 to 12 March 2026 |
| 20 Mar 2026 | 8326.5 µg/m³ | Europe, 18 to 25 March 2026 |
| 18 Jan 2026 | 8225.8 µg/m³ | – |
| 7 Mar 2026 | 7522.1 µg/m³ | Europe, 1 to 12 March 2026 |
| 25 Apr 2025 | 7421.4 µg/m³ | – |
| 4 Mar 2026 | 7321.0 µg/m³ | Europe, 1 to 12 March 2026 |
| 21 Mar 2026 | 7320.7 µg/m³ | Europe, 18 to 25 March 2026 |
| 3 Feb 2026 | 7220.3 µg/m³ | – |
Daily means, the highest since 27 Mar 2025; 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, Westbury, United Kingdom, 27 Mar 2025 – 8 Oct 2026. Monitor data from Clarity via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/gb/westbury/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.
Westbury now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-13 05:07 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).