SmogRank / Japan / Gifu / Gero
Gero, month by month
Gero has a measured daily mean on 955 days since 28 July 2023. Its worst month was July 2025, at 54 US AQI (10.7 µg/m³), 1,116th of 2,889 cities on that month's world ranking. Its cleanest was February 2024, at 17 US AQI (3.1 µg/m³).
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
7 months
| Month | Why |
|---|---|
| May 2025 | 17 of 31 days measured; a month needs 22. The others: 14 with under 18 hours of readings or readings that failed our checks. |
| Apr 2025 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Mar 2025 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Feb 2025 | No day measured. The others: 28 with under 18 hours of readings or readings that failed our checks. |
| Jan 2025 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Dec 2024 | 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 | 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.
Gero's worst months
| Month | US AQI | World rank |
|---|---|---|
| July 2025 | 5410.7 µg/m³ | 1,116thof 2,889 |
| July 2026 | 5310.0 µg/m³ | 1,357thof 2,784 |
| August 2025 | 529.8 µg/m³ | 1,278thof 2,901 |
| June 2025 | 519.1 µg/m³ | 1,571stof 2,508 |
| April 2024 | 509.0 µg/m³ | 1,165thof 2,520 |
| June 2024 | 437.8 µg/m³ | 1,392ndof 2,563 |
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.
Gero's worst days
| Day | US AQI |
|---|---|
| 21 May 2025 | 7823.8 µg/m³ |
| 5 Aug 2025 | 7823.6 µg/m³ |
| 2 Jul 2025 | 7622.7 µg/m³ |
| 22 Jul 2026 | 7421.7 µg/m³ |
| 19 Apr 2024 | 7421.6 µg/m³ |
| 9 Jul 2025 | 7421.6 µg/m³ |
| 18 Apr 2024 | 7421.4 µg/m³ |
| 4 Aug 2025 | 7421.3 µg/m³ |
| 10 Jul 2025 | 7220.6 µg/m³ |
| 3 Jul 2025 | 7119.7 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, Gero, 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/gero/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.
Gero 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).