SmogRank / Japan / Oita / Tsukumiura

Tsukumiura, month by month

Tsukumiura has a measured daily mean on 748 days since 28 July 2023. Its worst month was July 2026, at 55 US AQI (11.5 µg/m³), 996th of 2,784 cities on that month's world ranking. Its cleanest was August 2026, at 37 US AQI (6.7 µg/m³).

Every month since 2023

202647 so far274 days measured1,588th of 2,793 in the world
Jan44#1,495Feb51#1,638Mar53#1,648Apr46#1,480May48#1,106Jun38#1,550Jul55#996Aug37#2,212Sep41#1,179Oct44#1,148
2025too few days for a mean (a year needs 256)174 days measured
Jan12 daysFeb9 daysMar54#1,490Apr55#870May17 daysJun52#1,326Jul13 daysAug20 daysSep8 daysOct8 daysNov12 daysDec9 days
2024too few days for a mean (a year needs 257)200 days measured
Jan17 daysFeb13 daysMar19 daysApr52#1,061May19 daysJun17 daysJul19 daysAug18 daysSep17 daysOct11 daysNov15 daysDec11 days
2023too few days for a mean (a year needs 256)100 days measured
JanFebMarAprMayJunJul2 daysAug12 daysSep42#1,317Oct47#649Nov43#1,236Dec16 days
Each square is a month's mean PM2.5 in US AQI from Tsukumiura'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 Tsukumiura marked; each year, the year's. A dashed square is the running month, so far.
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
Dec 20259 of 31 days measured; a month needs 22. The others: 22 with under 18 hours of readings or readings that failed our checks.
Nov 202512 of 30 days measured; a month needs 21. The others: 18 with under 18 hours of readings or readings that failed our checks.
Oct 20258 of 31 days measured; a month needs 22. The others: 23 with under 18 hours of readings or readings that failed our checks.
Sep 20258 of 30 days measured; a month needs 21. The others: 22 with under 18 hours of readings or readings that failed our checks.
Aug 202520 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks.
Jul 202513 of 31 days measured; a month needs 22. The others: 18 with under 18 hours of readings or readings that failed our checks.
May 202517 of 31 days measured; a month needs 22. The others: 14 with under 18 hours of readings or readings that failed our checks.
Feb 20259 of 28 days measured; a month needs 20. The others: 19 with under 18 hours of readings or readings that failed our checks.
Jan 202512 of 31 days measured; a month needs 22. The others: 19 with under 18 hours of readings or readings that failed our checks.
Dec 202411 of 31 days measured; a month needs 22. The others: 20 with under 18 hours of readings or readings that failed our checks.
Nov 202415 of 30 days measured; a month needs 21. The others: 15 with under 18 hours of readings or readings that failed our checks.
Oct 202411 of 31 days measured; a month needs 22. The others: 20 with under 18 hours of readings or readings that failed our checks.
Sep 202417 of 30 days measured; a month needs 21. The others: 13 with under 18 hours of readings or readings that failed our checks.
Aug 202418 of 31 days measured; a month needs 22. The others: 13 with under 18 hours of readings or readings that failed our checks.
Jul 202419 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks.
Jun 202417 of 30 days measured; a month needs 21. The others: 13 with under 18 hours of readings or readings that failed our checks.
May 202419 of 31 days measured; a month needs 22. The others: 12 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 202413 of 29 days measured; a month needs 21. The others: 1 missing from OpenAQ's archive, 15 with under 18 hours of readings or readings that failed our checks.
Jan 202417 of 31 days measured; a month needs 22. The others: 14 with under 18 hours of readings or readings that failed our checks.
Dec 202316 of 31 days measured; a month needs 22. The others: 15 with under 18 hours of readings or readings that failed our checks.
Aug 202312 of 31 days measured; a month needs 22. The others: 19 with under 18 hours of readings or readings that failed our checks.
Jul 20232 of 31 days measured; a month needs 22. The others: 2 with under 18 hours of readings or readings that failed our checks.

A day counts once 18 hours of it are measured; a month needs 70% of its days.

Tsukumiura's worst months

MonthUS AQIDays measuredWorld rankEpisode
July 2026 5511.5 µg/m³31 of 31996thof 2,784Japan and South Korea, July 2026
April 2025 5511.3 µg/m³21 of 30870thof 2,951–
March 2025 5410.6 µg/m³23 of 311,490thof 2,862–
March 2026 5310.1 µg/m³31 of 311,648thof 2,971–
June 2025 529.9 µg/m³22 of 301,326thof 2,508Japan and South Korea, June and July 2025
April 2024 529.7 µg/m³24 of 301,061stof 2,520–

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.

Tsukumiura's worst days

DayUS AQIEpisode
3 Jul 2025 13348.4 µg/m³Japan and South Korea, June and July 2025
4 Jul 2025 12947.0 µg/m³Japan and South Korea, June and July 2025
5 Jul 2025 9633.5 µg/m³Japan and South Korea, June and July 2025
2 Jul 2025 9432.2 µg/m³Japan and South Korea, June and July 2025
2 Dec 2025 8326.2 µg/m³–
21 Jul 2026 8326.1 µg/m³Japan and South Korea, July 2026
29 Mar 2026 8024.9 µg/m³–
9 Jul 2025 7823.7 µg/m³Japan and South Korea, June and July 2025
2 Mar 2025 7722.9 µg/m³–
19 Apr 2024 7522.0 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, Tsukumiura, 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/tsukumiura/history (accessed 12 Oct 2026).

Download chart (PNG)

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.

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

Updated 2026-10-12 22:07 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).