SmogRank / Japan / Hyōgo / Sumoto
Sumoto, month by month
Sumoto has a measured daily mean on 978 days since 28 July 2023. Its worst month was July 2026, at 59 US AQI (13.6 µg/m³), 644th of 2,784 cities on that month's world ranking. Its cleanest was October 2025, at 24 US AQI (4.3 µg/m³). 2025 averaged 42 US AQI (7.5 µg/m³), against 32 US AQI (5.7 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 | 15 of 30 days measured; a month needs 21. The others: 15 with under 18 hours of readings or readings that failed our checks. |
| May 2026 | 21 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks. |
| Feb 2025 | 13 of 28 days measured; a month needs 20. The others: 15 with under 18 hours of readings or readings that failed our checks. |
| Dec 2024 | 19 of 31 days measured; a month needs 22. The others: 12 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. |
| May 2024 | 20 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks. |
| Feb 2024 | 16 of 29 days measured; a month needs 21. The others: 1 missing from OpenAQ's archive, 12 with under 18 hours of readings or readings that failed our checks. |
| Jul 2023 | 3 of 31 days measured; a month needs 22. The others: 1 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.
Sumoto's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| July 2026 | 5913.6 µg/m³ | 644thof 2,784 | Japan and South Korea, July 2026 |
| February 2026 | 5812.7 µg/m³ | 955thof 2,866 | Japan, 14 to 15 February 2026 |
| August 2025 | 5511.0 µg/m³ | 1,001stof 2,901 | – |
| March 2026 | 5410.6 µg/m³ | 1,515thof 2,971 | – |
| July 2025 | 5310.3 µg/m³ | 1,201stof 2,889 | Japan and South Korea, June and July 2025 |
| April 2026 | 5310.0 µg/m³ | 950thof 2,941 | – |
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.
Sumoto's worst days
| Day | US AQI | Episode |
|---|---|---|
| 23 Jul 2026 | 9834.2 µg/m³ | Japan and South Korea, July 2026 |
| 18 Apr 2024 | 9633.0 µg/m³ | Japan and South Korea, April 2024 |
| 5 Jul 2025 | 9030.3 µg/m³ | Japan and South Korea, June and July 2025 |
| 9 Jul 2025 | 9029.8 µg/m³ | Japan and South Korea, June and July 2025 |
| 22 Jul 2026 | 8929.5 µg/m³ | Japan and South Korea, July 2026 |
| 4 Jul 2025 | 8728.4 µg/m³ | Japan and South Korea, June and July 2025 |
| 15 Feb 2026 | 8527.3 µg/m³ | Japan, 14 to 15 February 2026 |
| 16 Feb 2026 | 7924.2 µg/m³ | – |
| 17 Jan 2026 | 7723.1 µg/m³ | – |
| 26 Mar 2025 | 7722.8 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, Sumoto, 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/sumoto/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.
Sumoto now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 17:07 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).