SmogRank / Japan / Chiba / Sakura

Sakura, month by month

Sakura has a measured daily mean on 1,130 days since 28 July 2023. Its worst month was July 2024, at 58 US AQI (12.8 µg/m³), 323rd of 2,566 cities on that month's world ranking. Its cleanest was February 2024, at 32 US AQI (5.7 µg/m³). 2025 averaged 52 US AQI (9.6 µg/m³), against 43 US AQI (7.7 µg/m³) in 2024.

Every month since 2023

2023too few days for a mean (a year needs 256)142 days measured
Each square is a month's mean PM2.5 in US AQI from Sakura'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 Sakura 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

1 month
MonthWhy
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.

Sakura's worst months

MonthUS AQIDays measuredWorld rankEpisode
July 2024 5812.8 µg/m³31 of 31323rdof 2,566–
August 2025 5812.8 µg/m³31 of 31606thof 2,901Chiba, Ibaraki and Yamanashi, Japan, August 2025
December 2025 5611.8 µg/m³31 of 31996thof 3,006Japan, December 2025
July 2025 5511.4 µg/m³31 of 31961stof 2,889Japan and South Korea, June and July 2025
July 2026 5511.4 µg/m³31 of 311,021stof 2,784Japan and South Korea, July 2026
Japan, July 2026
November 2025 5511.2 µg/m³26 of 30848thof 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.

Sakura's worst days

DayUS AQIEpisode
7 Jul 2025 11541.1 µg/m³Japan and South Korea, June and July 2025
6 Jul 2025 10637.6 µg/m³Japan and South Korea, June and July 2025
8 Jul 2025 9834.3 µg/m³Japan and South Korea, June and July 2025
9 Jul 2025 9231.3 µg/m³Japan and South Korea, June and July 2025
26 Mar 2025 9130.6 µg/m³Japan and South Korea, March 2025
20 Dec 2025 8728.2 µg/m³Japan, December 2025
16 Jul 2026 8426.9 µg/m³Japan and South Korea, July 2026
Japan, July 2026
18 Apr 2024 8326.5 µg/m³Japan and South Korea, April 2024
30 Aug 2025 8225.6 µg/m³Chiba, Ibaraki and Yamanashi, Japan, August 2025
20 May 2025 8225.5 µg/m³Japan, May 2025

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, Sakura, 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/sakura/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.

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

Updated 2026-10-12 17:07 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).