SmogRank / Belgium / Wallonia / Mons
Mons, month by month
Mons has a measured daily mean on 1,179 days since 11 January 2023. Its worst month was February 2025, at 69 US AQI (18.5 µg/m³), 664th of 2,633 cities on that month's world ranking. Its cleanest was April 2024, at 18 US AQI (3.2 µg/m³). 2025 averaged 51 US AQI (9.2 µg/m³), against 45 US AQI (8.1 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
8 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. |
| Nov 2025 | 20 of 30 days measured; a month needs 21. The others: 10 with under 18 hours of readings or readings that failed our checks. |
| Jun 2025 | 19 of 30 days measured; a month needs 21. The others: 11 with under 18 hours of readings or readings that failed our checks. |
| Oct 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. |
| 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. |
| Mar 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. |
| 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.
Mons's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| February 2025 | 6918.5 µg/m³ | 664thof 2,633 | Europe, 14 February to 1 March 2025 Europe, 1 to 14 February 2025 |
| February 2023 | 6818.2 µg/m³ | 180thof 1,129 | Europe, 6 to 25 February 2023 |
| March 2025 | 6516.8 µg/m³ | 786thof 2,862 | Europe, March 2025 Germany, Poland and 25 more countries, March 2025and 1 more |
| March 2026 | 6114.7 µg/m³ | 877thof 2,971 | Europe, 18 to 25 March 2026 Europe, 1 to 12 March 2026 |
| April 2023 | 5812.6 µg/m³ | 233rdof 1,622 | France, Belgium and Germany, April 2023 Europe, April 2023 |
| January 2025 | 5712.2 µg/m³ | 710thof 2,474 | Germany, France and 19 more countries, January 2025 Europe, January 2025and 2 more |
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.
Mons's worst days
| Day | US AQI | Episode |
|---|---|---|
| 25 Mar 2025 | 13348.3 µg/m³ | Europe, March 2025 |
| 15 Feb 2023 | 13248.1 µg/m³ | Europe, 6 to 25 February 2023 |
| 13 Feb 2023 | 12645.6 µg/m³ | Europe, 6 to 25 February 2023 |
| 14 Feb 2023 | 12445.0 µg/m³ | Europe, 6 to 25 February 2023 |
| 7 Mar 2026 | 11842.5 µg/m³ | Europe, 1 to 12 March 2026 |
| 26 Jan 2026 | 11641.4 µg/m³ | Europe, January and February 2026 |
| 8 Mar 2026 | 11340.3 µg/m³ | Europe, 1 to 12 March 2026 |
| 15 Jan 2025 | 11239.8 µg/m³ | Germany, France and 19 more countries, January 2025 Europe, January 2025 |
| 10 Feb 2025 | 10938.7 µg/m³ | Europe, 1 to 14 February 2025 |
| 10 Feb 2023 | 10838.5 µg/m³ | Europe, 6 to 25 February 2023 |
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, Mons, Belgium, 11 Jan 2023 – 12 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/be/mons/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.
Mons now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 23:07 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).