SmogRank / Japan / Kochi / Aki
Aki, month by month
Aki has a measured daily mean on 1,034 days since 28 July 2023. Its worst month was July 2026, at 62 US AQI (14.8 µg/m³), 531st of 2,784 cities on that month's world ranking. Its cleanest was October 2024, at 29 US AQI (5.3 µg/m³). 2025 averaged 48 US AQI (8.7 µg/m³), against 41 US AQI (7.3 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
5 months
| Month | Why |
|---|---|
| Aug 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. |
| Nov 2023 | 20 of 30 days measured; a month needs 21. The others: 10 with under 18 hours of readings or readings that failed our checks. |
| Sep 2023 | 18 of 30 days measured; a month needs 21. The others: 12 with under 18 hours of readings or readings that failed our checks. |
| Aug 2023 | 17 of 31 days measured; a month needs 22. The others: 14 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.
Aki's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| July 2026 | 6214.8 µg/m³ | 531stof 2,784 | Japan and South Korea, July 2026 |
| July 2025 | 5612.0 µg/m³ | 839thof 2,889 | Japan and South Korea, June and July 2025 |
| August 2025 | 5410.9 µg/m³ | 1,027thof 2,901 | – |
| June 2025 | 5310.4 µg/m³ | 1,179thof 2,508 | Japan and South Korea, June and July 2025 |
| March 2025 | 529.9 µg/m³ | 1,609thof 2,862 | – |
| April 2025 | 529.8 µg/m³ | 1,229thof 2,951 | – |
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.
Aki's worst days
| Day | US AQI | Episode |
|---|---|---|
| 5 Jul 2025 | 13951.0 µg/m³ | Japan and South Korea, June and July 2025 |
| 6 Jul 2025 | 11340.5 µg/m³ | Japan and South Korea, June and July 2025 |
| 24 Jul 2026 | 9331.9 µg/m³ | Japan and South Korea, July 2026 |
| 25 Jul 2026 | 9030.0 µg/m³ | Japan and South Korea, July 2026 |
| 9 Jul 2025 | 8627.8 µg/m³ | Japan and South Korea, June and July 2025 |
| 7 Jul 2025 | 8527.5 µg/m³ | Japan and South Korea, June and July 2025 |
| 4 Jul 2025 | 8426.7 µg/m³ | Japan and South Korea, June and July 2025 |
| 28 Jul 2026 | 8326.1 µg/m³ | – |
| 8 Jul 2025 | 8125.3 µg/m³ | Japan and South Korea, June and July 2025 |
| 19 Apr 2024 | 7823.8 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, Aki, 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/aki/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.
Aki now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 18:07 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).