SmogRank / France / Brittany / Brest
Brest, month by month
Brest, Brittany has a measured daily mean on 995 days since 11 January 2023. Its worst month was February 2025, at 58 US AQI (12.6 µg/m³), 980th of 2,633 cities on that month's world ranking. Its cleanest was July 2023, at 28 US AQI (5.0 µg/m³). 2025 averaged 47 US AQI (8.4 µg/m³), against 42 US AQI (7.6 µg/m³) in 2023.
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
16 months
| Month | Why |
|---|---|
| Jun 2026 | 18 of 30 days measured; a month needs 21. The others: 12 with under 18 hours of readings or readings that failed our checks. |
| Oct 2025 | 9 of 31 days measured; a month needs 22. The others: 22 with under 18 hours of readings or readings that failed our checks. |
| Aug 2025 | 21 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks. |
| Jun 2025 | 16 of 30 days measured; a month needs 21. The others: 14 with under 18 hours of readings or readings that failed our checks. |
| May 2025 | 21 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks. |
| Dec 2024 | 18 of 31 days measured; a month needs 22. The others: 13 with under 18 hours of readings or readings that failed our checks. |
| Oct 2024 | 13 of 31 days measured; a month needs 22. The others: 18 with under 18 hours of readings or readings that failed our checks. |
| Sep 2024 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Aug 2024 | 15 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks. |
| Jun 2024 | 2 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks. |
| May 2024 | 1 of 31 days measured; a month needs 22. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Apr 2024 | 2 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks. |
| Mar 2024 | 10 of 31 days measured; a month needs 22. The others: 21 with under 18 hours of readings or readings that failed our checks. |
| Apr 2023 | 3 of 30 days measured; a month needs 21. The others: 27 with under 18 hours of readings or readings that failed our checks. |
| Mar 2023 | 20 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks. |
| Jan 2023 | 7 of 31 days measured; a month needs 22. The others: 14 with under 18 hours of readings or readings that failed our checks. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Brest's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| February 2025 | 5812.6 µg/m³ | 980thof 2,633 | Europe, 1 to 14 February 2025 |
| March 2026 | 5611.8 µg/m³ | 1,252ndof 2,971 | Europe, 18 to 25 March 2026 |
| March 2025 | 5511.3 µg/m³ | 1,348thof 2,862 | Europe, March 2025 |
| January 2025 | 5511.0 µg/m³ | 835thof 2,474 | – |
| January 2024 | 5310.4 µg/m³ | 839thof 2,385 | – |
| December 2025 | 5310.2 µg/m³ | 1,287thof 3,006 | – |
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.
Brest's worst days
| Day | US AQI | Episode |
|---|---|---|
| 21 Mar 2026 | 10135.7 µg/m³ | Europe, 18 to 25 March 2026 |
| 24 Mar 2025 | 9029.9 µg/m³ | Europe, March 2025 |
| 23 Mar 2026 | 8929.7 µg/m³ | Europe, 18 to 25 March 2026 |
| 20 Mar 2026 | 8426.8 µg/m³ | Europe, 18 to 25 March 2026 |
| 11 Feb 2025 | 8326.3 µg/m³ | Europe, 1 to 14 February 2025 |
| 13 Dec 2024 | 7924.1 µg/m³ | – |
| 8 Mar 2026 | 7924.0 µg/m³ | – |
| 11 Mar 2025 | 7823.8 µg/m³ | – |
| 9 Sept 2023 | 7823.4 µg/m³ | – |
| 17 Feb 2025 | 7723.1 µg/m³ | – |
Daily means, the highest since 11 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, Brest, Brittany, France, 11 Jan 2023 – 11 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/fr/brest/history (accessed 12 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.
Brest now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 18:07 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).