SmogRank / Japan / Saga / Imarichō-kō
Imarichō-kō, month by month
Imarichō-kō has a measured daily mean on 1,153 days since 28 July 2023. Its worst month was April 2024, at 62 US AQI (14.9 µg/m³), 411th of 2,520 cities on that month's world ranking. Its cleanest was July 2024, at 31 US AQI (5.5 µg/m³). 2025 averaged 53 US AQI (10.0 µg/m³), against 53 US AQI (10.0 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
1 month
| Month | Why |
|---|---|
| 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.
Imarichō-kō's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| April 2024 | 6214.9 µg/m³ | 411thof 2,520 | Japan and South Korea, April 2024 |
| November 2025 | 5812.8 µg/m³ | 695thof 2,715 | – |
| May 2024 | 5712.4 µg/m³ | 442ndof 2,684 | – |
| March 2026 | 5712.1 µg/m³ | 1,199thof 2,971 | Japan and South Korea, March 2026 |
| March 2025 | 5612.0 µg/m³ | 1,242ndof 2,862 | – |
| November 2023 | 5611.9 µg/m³ | 304thof 2,243 | – |
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.
Imarichō-kō's worst days
| Day | US AQI | Episode |
|---|---|---|
| 19 Apr 2024 | 13448.8 µg/m³ | Japan and South Korea, April 2024 |
| 11 Feb 2024 | 11039.3 µg/m³ | Japan, 11 to 12 February 2024 |
| 18 Apr 2024 | 9733.6 µg/m³ | Japan and South Korea, April 2024 |
| 28 Mar 2026 | 9030.0 µg/m³ | Japan and South Korea, March 2026 |
| 21 Jan 2025 | 8728.5 µg/m³ | Japan and South Korea, 17 to 24 January 2025 |
| 14 Jun 2024 | 8527.5 µg/m³ | South Korea and Japan, June 2024 |
| 22 Jan 2025 | 8527.4 µg/m³ | Japan and South Korea, 17 to 24 January 2025 |
| 15 Jun 2024 | 8427.0 µg/m³ | South Korea and Japan, June 2024 |
| 20 Apr 2024 | 8226.0 µg/m³ | Japan and South Korea, April 2024 |
| 27 Feb 2025 | 8024.5 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, Imarichō-kō, 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/imaricho-ko/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.
Imarichō-kō now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 19:07 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).