SmogRank / Japan / Hokkaido / Asahikawa
Asahikawa, month by month
Asahikawa has a measured daily mean on 1,112 days since 28 July 2023. Its worst month was January 2024, at 56 US AQI (11.6 µg/m³), 735th of 2,385 cities on that month's world ranking. Its cleanest was September 2024, at 27 US AQI (4.8 µg/m³). 2025 averaged 42 US AQI (7.5 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
2 months
| Month | Why |
|---|---|
| Sep 2025 | 14 of 30 days measured; a month needs 21. The others: 16 with under 18 hours of readings or readings that failed our checks. |
| Jul 2023 | 4 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.
Asahikawa's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| January 2024 | 5611.6 µg/m³ | 735thof 2,385 | – |
| July 2024 | 5511.3 µg/m³ | 520thof 2,566 | Japan, 12 to 14 July 2024 |
| March 2026 | 5511.0 µg/m³ | 1,423rdof 2,971 | Japan and South Korea, March 2026 |
| February 2024 | 5410.7 µg/m³ | 582ndof 2,486 | Hokkaido and Aomori, Japan, February 2024 |
| January 2025 | 5410.7 µg/m³ | 884thof 2,474 | – |
| November 2025 | 529.4 µg/m³ | 1,164thof 2,715 | – |
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.
Asahikawa's worst days
| Day | US AQI | Episode |
|---|---|---|
| 24 Dec 2024 | 10738.0 µg/m³ | – |
| 14 Feb 2024 | 9532.5 µg/m³ | Hokkaido and Aomori, Japan, February 2024 |
| 23 Dec 2024 | 9130.4 µg/m³ | – |
| 11 Jul 2024 | 8929.3 µg/m³ | – |
| 4 Jan 2024 | 8728.5 µg/m³ | – |
| 12 Jul 2024 | 8527.4 µg/m³ | Japan, 12 to 14 July 2024 |
| 6 Nov 2025 | 8527.2 µg/m³ | – |
| 22 Dec 2024 | 8427.0 µg/m³ | – |
| 23 Jan 2025 | 8427.0 µg/m³ | – |
| 18 Jan 2024 | 8426.9 µg/m³ | – |
Daily means, the highest since 28 Jul 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, Asahikawa, Japan, 28 Jul 2023 – 12 Oct 2026. Monitor data from Ministry of the Environment Air Pollutant Wide Area Monitoring System via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/jp/asahikawa/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.
Asahikawa now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 21:07 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).