SmogRank / Japan / Akita / Oga
Oga, month by month
Oga has a measured daily mean on 1,055 days since 28 July 2023. Its worst month was March 2026, at 57 US AQI (12.2 µg/m³), 1,175th of 2,971 cities on that month's world ranking. Its cleanest was December 2024, at 24 US AQI (4.4 µg/m³). 2025 averaged 47 US AQI (8.5 µg/m³), against 41 US AQI (7.4 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 |
|---|---|
| Oct 2026 | No day measured. The others: 11 with no readings from the monitor, 1 with under 18 hours of readings or readings that failed our checks. |
| Sep 2026 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Aug 2026 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Jul 2026 | 16 of 31 days measured; a month needs 22. The others: 15 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.
Oga's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| March 2026 | 5712.2 µg/m³ | 1,175thof 2,971 | Japan and South Korea, March 2026 |
| April 2024 | 5511.4 µg/m³ | 813thof 2,520 | Japan and South Korea, April 2024 |
| July 2024 | 5511.4 µg/m³ | 506thof 2,566 | Japan, 12 to 14 July 2024 |
| July 2025 | 5410.8 µg/m³ | 1,097thof 2,889 | Japan and South Korea, June and July 2025 |
| March 2025 | 5410.7 µg/m³ | 1,479thof 2,862 | Japan and South Korea, March 2025 |
| April 2025 | 529.9 µg/m³ | 1,197thof 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.
Oga's worst days
| Day | US AQI | Episode |
|---|---|---|
| 18 Apr 2024 | 9130.6 µg/m³ | Japan and South Korea, April 2024 |
| 15 Jul 2024 | 8829.1 µg/m³ | – |
| 14 Feb 2026 | 8728.4 µg/m³ | Japan, 14 to 15 February 2026 |
| 14 Jul 2024 | 8627.9 µg/m³ | Japan, 12 to 14 July 2024 |
| 30 Mar 2026 | 8527.6 µg/m³ | Japan and South Korea, March 2026 |
| 26 Apr 2025 | 8326.3 µg/m³ | – |
| 25 Mar 2025 | 8226.0 µg/m³ | Japan and South Korea, March 2025 |
| 24 Mar 2026 | 8225.9 µg/m³ | Japan and South Korea, March 2026 |
| 4 Jul 2025 | 8225.7 µg/m³ | Japan and South Korea, June and July 2025 |
| 29 Mar 2026 | 8024.5 µg/m³ | Japan and South Korea, March 2026 |
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, Oga, Japan, 28 Jul 2023 – 16 Jul 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/oga/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.
Oga 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).