SmogRank / Japan / Chiba / Kōzaki
Kōzaki, month by month
Kōzaki has a measured daily mean on 843 days since 2 May 2024. Its worst month was July 2024, at 59 US AQI (13.2 µg/m³), 283rd of 2,566 cities on that month's world ranking. Its cleanest was September 2026, at 27 US AQI (4.8 µg/m³).
Every month since 2024
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
Kōzaki's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| July 2024 | 5913.2 µg/m³ | 283rdof 2,566 | Japan, 6 to 8 July 2024 |
| August 2025 | 5611.7 µg/m³ | 846thof 2,901 | – |
| July 2025 | 529.8 µg/m³ | 1,310thof 2,889 | Japan and South Korea, June and July 2025 |
| July 2026 | 529.8 µg/m³ | 1,413thof 2,784 | – |
| December 2025 | 519.3 µg/m³ | 1,517thof 3,006 | – |
| November 2025 | 519.2 µg/m³ | 1,202ndof 2,715 | – |
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.
Kōzaki's worst days
| Day | US AQI | Episode |
|---|---|---|
| 6 Jul 2025 | 10135.6 µg/m³ | Japan and South Korea, June and July 2025 |
| 7 Jul 2025 | 10135.5 µg/m³ | Japan and South Korea, June and July 2025 |
| 8 Jul 2025 | 9532.8 µg/m³ | Japan and South Korea, June and July 2025 |
| 26 Mar 2025 | 8828.8 µg/m³ | Japan and South Korea, March 2025 |
| 9 Jul 2025 | 8427.0 µg/m³ | Japan and South Korea, June and July 2025 |
| 8 Jul 2024 | 8326.1 µg/m³ | Japan, 6 to 8 July 2024 |
| 16 Jul 2026 | 7924.0 µg/m³ | – |
| 24 Aug 2025 | 7723.0 µg/m³ | – |
| 22 Jul 2026 | 7622.3 µg/m³ | – |
| 20 May 2025 | 7421.5 µg/m³ | – |
Daily means, the highest since 2 May 2024; 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, Kōzaki, Japan, 2 May 2024 – 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/kozaki/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.
Kōzaki now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 21:07 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).