SmogRank / Japan / Fukushima / Fukushima

Fukushima, month by month

Fukushima has a measured daily mean on 732 days since 28 July 2023. Its worst month was April 2024, at 63 US AQI (15.6 µg/m³), 379th of 2,520 cities on that month's world ranking. Its cleanest was February 2025, at 41 US AQI (7.3 µg/m³).

Every month since 2023

2026too few days for a mean (a year needs 200)185 days measured
Jan7 daysFeb52#1,482Mar58#1,054Apr19 daysMay56#600Jun20 daysJul57#884Aug18 daysSep19 daysOct6 days
2025too few days for a mean (a year needs 256)245 days measured
Jan19 daysFeb41#1,752Mar58#1,116Apr19 daysMay53#809Jun55#938Jul57#731Aug53#1,173Sep14 daysOct43#934Nov8 daysDec12 days
2024too few days for a mean (a year needs 257)217 days measured
Jan14 daysFeb14 daysMar19 daysApr63#379May14 daysJun54#479Jul55#520Aug50#874Sep19 daysOct20 daysNov11 daysDec12 days
2023too few days for a mean (a year needs 256)85 days measured
JanFebMarAprMayJunJul4 daysAug53#573Sep46#1,047Oct13 daysNov9 daysDec15 days
Each square is a month's mean PM2.5 in US AQI from Fukushima's measured days, with its place on that month's world ranking under it. A month has a mean once 70% of its days are measured, the rule the monthly rankings use; under that, the square gives the days measured. Each square opens that month's ranking with Fukushima marked; each year, the year's.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

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

23 months
MonthWhy
Oct 20266 of 12 days measured; a month needs 9. The others: 6 with readings for part of the day (a day needs 18 hours).
Sep 202619 of 30 days measured; a month needs 21. The others: 11 with readings for part of the day (a day needs 18 hours).
Aug 202618 of 31 days measured; a month needs 22. The others: 13 with under 18 hours of readings or readings that failed our checks.
Jun 202620 of 30 days measured; a month needs 21. The others: 10 with under 18 hours of readings or readings that failed our checks.
Apr 202619 of 30 days measured; a month needs 21. The others: 11 with under 18 hours of readings or readings that failed our checks.
Jan 20267 of 31 days measured; a month needs 22. The others: 24 with under 18 hours of readings or readings that failed our checks.
Dec 202512 of 31 days measured; a month needs 22. The others: 19 with under 18 hours of readings or readings that failed our checks.
Nov 20258 of 30 days measured; a month needs 21. The others: 22 with under 18 hours of readings or readings that failed our checks.
Sep 202514 of 30 days measured; a month needs 21. The others: 16 with under 18 hours of readings or readings that failed our checks.
Apr 202519 of 30 days measured; a month needs 21. The others: 11 with under 18 hours of readings or readings that failed our checks.
Jan 202519 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks.
Dec 202412 of 31 days measured; a month needs 22. The others: 19 with under 18 hours of readings or readings that failed our checks.
Nov 202411 of 30 days measured; a month needs 21. The others: 19 with under 18 hours of readings or readings that failed our checks.
Oct 202420 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks.
Sep 202419 of 30 days measured; a month needs 21. The others: 11 with under 18 hours of readings or readings that failed our checks.
May 202414 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks.
Mar 202419 of 31 days measured; a month needs 22. The others: 1 missing from OpenAQ's archive, 11 with under 18 hours of readings or readings that failed our checks.
Feb 202414 of 29 days measured; a month needs 21. The others: 1 missing from OpenAQ's archive, 14 with under 18 hours of readings or readings that failed our checks.
Jan 202414 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks.
Dec 202315 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks.
Nov 20239 of 30 days measured; a month needs 21. The others: 21 with under 18 hours of readings or readings that failed our checks.
Oct 202313 of 31 days measured; a month needs 22. The others: 18 with under 18 hours of readings or readings that failed our checks.
Jul 20234 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.

Fukushima's worst months

MonthUS AQIDays measuredWorld rankEpisode
April 2024 6315.6 µg/m³22 of 30379thof 2,520Japan and South Korea, April 2024
March 2026 5813.1 µg/m³23 of 311,054thof 2,971–
March 2025 5812.9 µg/m³24 of 311,116thof 2,862Japan and South Korea, March 2025
July 2025 5712.5 µg/m³30 of 31731stof 2,889Japan and South Korea, June and July 2025
July 2026 5712.1 µg/m³27 of 31884thof 2,784–
May 2026 5611.6 µg/m³24 of 31600thof 2,874–

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.

Fukushima's worst days

DayUS AQIEpisode
18 Apr 2024 12746.1 µg/m³Japan and South Korea, April 2024
26 Mar 2025 8728.4 µg/m³Japan and South Korea, March 2025
25 Mar 2025 8326.5 µg/m³Japan and South Korea, March 2025
19 Apr 2025 8125.4 µg/m³Japan, 19 to 20 April 2025
8 Jul 2025 8125.2 µg/m³Japan and South Korea, June and July 2025
14 Jul 2024 7924.2 µg/m³–
13 Jul 2024 7923.9 µg/m³–
27 Mar 2025 7823.8 µg/m³Japan and South Korea, March 2025
9 Jul 2025 7723.2 µg/m³Japan and South Korea, June and July 2025
30 Mar 2026 7723.2 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, Fukushima, 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/fukushima/history (accessed 12 Oct 2026).

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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.

Fukushima now: the last 24 hours, its ranks today and the last 12 months day by day.

Updated 2026-10-12 20:07 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).