SmogRank / Japan / Saitama / Kazo
Kazo, month by month
Kazo has a measured daily mean on 1,116 days since 28 July 2023. Its worst month was April 2024, at 61 US AQI (14.7 µg/m³), 424th of 2,520 cities on that month's world ranking. Its cleanest was September 2026, at 34 US AQI (6.2 µg/m³). 2025 averaged 52 US AQI (9.7 µg/m³), against 54 US AQI (10.9 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
6 months
| Month | Why |
|---|---|
| Oct 2026 | 6 of 12 days measured; a month needs 9. The others: 5 with no readings from the monitor, 1 with readings for part of the day (a day needs 18 hours). |
| Jul 2025 | 21 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks. |
| Mar 2025 | 18 of 31 days measured; a month needs 22. The others: 13 with under 18 hours of readings or readings that failed our checks. |
| Feb 2025 | 19 of 28 days measured; a month needs 20. The others: 9 with under 18 hours of readings or readings that failed our checks. |
| Oct 2024 | 19 of 31 days measured; a month needs 22. The others: 12 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.
Kazo's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| April 2024 | 6114.7 µg/m³ | 424thof 2,520 | Japan and South Korea, April 2024 |
| November 2023 | 6014.1 µg/m³ | 175thof 2,243 | Japan, November 2023 |
| December 2023 | 6013.8 µg/m³ | 323rdof 2,247 | Japan, 9 to 10 December 2023 |
| July 2024 | 5913.4 µg/m³ | 268thof 2,566 | – |
| October 2023 | 5511.3 µg/m³ | 224thof 2,012 | – |
| December 2025 | 5511.2 µg/m³ | 1,091stof 3,006 | Japan, December 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.
Kazo's worst days
| Day | US AQI | Episode |
|---|---|---|
| 4 Nov 2023 | 10737.9 µg/m³ | Japan, November 2023 |
| 21 Dec 2025 | 10537.1 µg/m³ | Japan, December 2025 |
| 18 Apr 2024 | 9331.9 µg/m³ | Japan and South Korea, April 2024 |
| 3 Nov 2023 | 9231.0 µg/m³ | Japan, November 2023 |
| 20 Apr 2024 | 9030.0 µg/m³ | Japan and South Korea, April 2024 |
| 26 Mar 2025 | 8728.5 µg/m³ | Japan and South Korea, March 2025 |
| 5 Aug 2025 | 8527.2 µg/m³ | Japan, 4 to 5 August 2025 |
| 25 Mar 2025 | 8326.3 µg/m³ | Japan and South Korea, March 2025 |
| 19 Apr 2025 | 8326.1 µg/m³ | Japan, 19 to 20 April 2025 |
| 19 Apr 2024 | 8226.0 µg/m³ | Japan and South Korea, April 2024 |
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, Kazo, Japan, 28 Jul 2023 – 6 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/kazo/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.
Kazo 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).