SmogRank / World / Japan / Nagano / July 2025

Most polluted cities in Nagano, Japan, July 2025

11 cities in Nagano, Japan ranked by their average PM2.5 over the 31 days. Worst: Iida at 11.6 µg/m³, #885 of 2,832 cities in the world. Cleanest: Obuse at 9.4. A city needs measurements on 70% of the days to be ranked.

Ranked by unhealthy days: the share of each city's measured days with a daily mean over 35.4 µg/m³ (US AQI 101+), Unhealthy for Sensitive Groups or worse on the US EPA's scale. Ties go to the higher average.

← Iida 0% 0.75%0
Every city in Nagano, Japan ranked for July 2025, one column each, ranked by unhealthy days: height is the share of its measured days that were unhealthy, colour its average. Point at it to read a city; tap to open it.
  1. 1Iida
    0%
  2. 1Chikuma
    0%
  3. 3Nagano
    0%
  4. 4Saku
    0%
  5. 5Ina
    0%
  6. 6Kiso
    0%
  7. 7Matsumoto
    0%
  8. 8Suwa
    0%
  9. 9Ueda
    0%
  10. 10Okaya
    0%
  11. 10Obuse
    0%
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

All cities in the world, July 2025 · All cities in Japan, July 2025 · Nagano now

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SmogRank, most polluted cities in Nagano, Japan, PM2.5, July 2025, smogrank.com/jp/region/nagano/history/2025-07 (accessed 6 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.