SmogRank / Belgium / Wallonia / Vielsalm
Vielsalm, month by month
Vielsalm has a measured daily mean on 1,055 days since 14 February 2023. Its worst month was February 2025, at 53 US AQI (10.0 µg/m³), 1,186th of 2,633 cities on that month's world ranking. Its cleanest was September 2025, at 4 US AQI (0.7 µg/m³). 2025 averaged 22 US AQI (4.0 µg/m³), against 20 US AQI (3.6 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
8 months
| Month | Why |
|---|---|
| Jun 2026 | 19 of 30 days measured; a month needs 21. The others: 6 with no readings from the monitor, 5 with readings for part of the day (a day needs 18 hours). |
| Jun 2025 | 17 of 30 days measured; a month needs 21. The others: 1 with no readings from the monitor, 12 with readings for part of the day (a day needs 18 hours). |
| Oct 2024 | 15 of 31 days measured; a month needs 22. The others: 16 with readings for part of the day (a day needs 18 hours). |
| Sep 2024 | No day measured. The others: 30 with readings for part of the day (a day needs 18 hours). |
| Aug 2024 | 13 of 31 days measured; a month needs 22. The others: 7 with no readings from the monitor, 11 with readings for part of the day (a day needs 18 hours). |
| Mar 2024 | 13 of 31 days measured; a month needs 22. The others: 10 with no readings from the monitor, 6 with readings for part of the day (a day needs 18 hours), 2 with readings left out by our checks. |
| Mar 2023 | 11 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive. |
| Feb 2023 | 2 of 28 days measured; a month needs 20. The others: 13 missing from OpenAQ's archive. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Vielsalm's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| February 2025 | 5310.0 µg/m³ | 1,186thof 2,633 | Europe, 1 to 14 February 2025 |
| March 2025 | 437.7 µg/m³ | 1,979thof 2,862 | Europe, March 2025 |
| January 2026 | 376.6 µg/m³ | 1,930thof 2,617 | Europe, January and February 2026 |
| March 2026 | 346.2 µg/m³ | 2,509thof 2,971 | – |
| May 2023 | 346.1 µg/m³ | 1,279thof 1,600 | – |
| August 2026 | 315.6 µg/m³ | 2,606thof 2,896 | Germany, Belgium and 2 more countries, August 2026 |
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.
Vielsalm's worst days
| Day | US AQI | Episode |
|---|---|---|
| 16 Aug 2026 | 16676.4 µg/m³ | Germany, Belgium and 2 more countries, August 2026 |
| 26 Jan 2026 | 9029.8 µg/m³ | Europe, January and February 2026 |
| 25 Jan 2026 | 8828.7 µg/m³ | Europe, January and February 2026 |
| 10 Feb 2025 | 8527.4 µg/m³ | Europe, 1 to 14 February 2025 |
| 25 Mar 2025 | 8426.6 µg/m³ | Europe, March 2025 |
| 22 May 2023 | 7723.0 µg/m³ | – |
| 11 Mar 2025 | 7320.9 µg/m³ | – |
| 20 Mar 2026 | 7019.5 µg/m³ | – |
| 13 Feb 2025 | 7019.3 µg/m³ | Europe, 1 to 14 February 2025 |
| 20 Feb 2025 | 7019.2 µg/m³ | – |
Daily means, the highest since 14 Feb 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, Vielsalm, Belgium, 14 Feb 2023 – 11 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/be/vielsalm/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.
Vielsalm now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 19:07 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).