SmogRank / Japan / Kanagawa / Isehara

Isehara, month by month

Isehara has a measured daily mean on 303 days since 28 November 2025. Its worst month was July 2026, at 58 US AQI (12.7 µg/m³), 775th of 2,784 cities on that month's world ranking. Its cleanest was January 2026, at 26 US AQI (4.6 µg/m³).

Every month since 2025

202644 so far273 days measured1,825th of 2,791 in the world

Jan26#2,399 Feb43#2,022 Mar44#2,137 Apr49#1,241 May47#1,136 Jun38#1,514 Jul58#775 Aug49#1,219 Sep28#2,284 Oct43#1,170

2025too few days for a mean (a year needs 256)30 days measured

JanFebMarAprMayJunJulAugSepOctNov3 daysDec38#2,203

Each square is a month's mean PM2.5 in US AQI from Isehara'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 Isehara 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

Month	Why
Nov 2025	3 of 30 days measured; a month needs 21.

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

Isehara's worst months

Month	US AQI	Days measured	World rank	Episode
July 2026	5812.7 µg/m³	31 of 31	775thof 2,784	Japan and South Korea, July 2026 Japan, July 2026
April 2026	498.9 µg/m³	30 of 30	1,241stof 2,941	–
August 2026	498.9 µg/m³	31 of 31	1,219thof 2,896	–
May 2026	478.5 µg/m³	31 of 31	1,136thof 2,874	–
March 2026	448.0 µg/m³	28 of 31	2,137thof 2,971	–
February 2026	437.8 µg/m³	28 of 28	2,022ndof 2,866	–

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.

Isehara's worst days

Day	US AQI	Episode
23 Jul 2026	8728.2 µg/m³	Japan and South Korea, July 2026
16 Jul 2026	8326.5 µg/m³	Japan and South Korea, July 2026 Japan, July 2026
22 Jul 2026	7723.2 µg/m³	Japan and South Korea, July 2026
1 Aug 2026	7622.6 µg/m³	–
31 Jul 2026	7421.5 µg/m³	–
2 Aug 2026	7320.9 µg/m³	–
17 Jul 2026	7220.4 µg/m³	Japan and South Korea, July 2026
25 Jul 2026	6919.0 µg/m³	Japan and South Korea, July 2026
13 Jul 2026	6717.5 µg/m³	–
15 Jul 2026	6617.4 µg/m³	–

Daily means, the highest since 28 Nov 2025; 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, Isehara, Japan, 28 Nov 2025 – 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/isehara/history (accessed 12 Oct 2026).

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Isehara 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).