SmogRank / Japan / Wakayama / Hashimoto
Hashimoto, month by month
Hashimoto has a measured daily mean on 979 days since 28 July 2023. Its worst month was July 2026, at 59 US AQI (13.2 µg/m³), 694th of 2,784 cities on that month's world ranking. Its cleanest was October 2024, at 32 US AQI (5.8 µg/m³). 2025 averaged 52 US AQI (9.4 µg/m³), against 44 US AQI (7.9 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
9 months
| Month | Why |
|---|---|
| Mar 2024 | 13 of 31 days measured; a month needs 22. The others: 1 missing from OpenAQ's archive, 17 with under 18 hours of readings or readings that failed our checks. |
| Feb 2024 | 3 of 29 days measured; a month needs 21. The others: 1 missing from OpenAQ's archive, 25 with under 18 hours of readings or readings that failed our checks. |
| Jan 2024 | 6 of 31 days measured; a month needs 22. The others: 25 with under 18 hours of readings or readings that failed our checks. |
| Dec 2023 | 9 of 31 days measured; a month needs 22. The others: 22 with under 18 hours of readings or readings that failed our checks. |
| Nov 2023 | 11 of 30 days measured; a month needs 21. The others: 19 with under 18 hours of readings or readings that failed our checks. |
| Oct 2023 | 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 2023 | 16 of 30 days measured; a month needs 21. The others: 14 with under 18 hours of readings or readings that failed our checks. |
| Aug 2023 | 8 of 31 days measured; a month needs 22. The others: 23 with under 18 hours of readings or readings that failed our checks. |
| Jul 2023 | 2 of 31 days measured; a month needs 22. The others: 2 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.
Hashimoto's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| July 2026 | 5913.2 µg/m³ | 694thof 2,784 | Japan and South Korea, July 2026 |
| August 2025 | 5812.9 µg/m³ | 587thof 2,901 | – |
| March 2025 | 5511.2 µg/m³ | 1,366thof 2,862 | Japan and South Korea, March 2025 |
| February 2026 | 5410.9 µg/m³ | 1,208thof 2,866 | – |
| April 2025 | 5410.8 µg/m³ | 985thof 2,951 | – |
| January 2025 | 5310.3 µg/m³ | 940thof 2,474 | Japan and South Korea, 31 January to 1 February 2025 |
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.
Hashimoto's worst days
| Day | US AQI | Episode |
|---|---|---|
| 18 Apr 2024 | 13448.8 µg/m³ | Japan and South Korea, April 2024 |
| 23 Jul 2026 | 9231.1 µg/m³ | Japan and South Korea, July 2026 |
| 9 Jul 2025 | 8829.2 µg/m³ | Japan and South Korea, June and July 2025 |
| 31 Jan 2025 | 8527.1 µg/m³ | Japan and South Korea, 31 January to 1 February 2025 |
| 1 Feb 2025 | 8226.0 µg/m³ | Japan and South Korea, 31 January to 1 February 2025 |
| 26 Mar 2025 | 8125.0 µg/m³ | Japan and South Korea, March 2025 |
| 24 Jul 2026 | 8024.9 µg/m³ | Japan and South Korea, July 2026 |
| 2 Mar 2025 | 7924.2 µg/m³ | – |
| 22 Jul 2026 | 7823.6 µg/m³ | Japan and South Korea, July 2026 |
| 25 Mar 2025 | 7823.4 µg/m³ | Japan and South Korea, March 2025 |
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, Hashimoto, 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/hashimoto/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.
Hashimoto 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).