SmogRank / World / Asia / Japan / Tochigi

Most polluted cities in Tochigi, Japan

11 measured cities, this year; 11 above the WHO annual guideline. Worst: Oyama at 9.2 µg/m³, #1,251 in the world.

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.

Gunma: 9 measured citiesIbaraki: 19 measured citiesNiigata: 12 measured citiesSaitama: 31 measured citiesTochigi: 11 measured citiesFukushima: 7 measured citiesChiba: 31 measured cities#11 Imaichi: 7.0 µg/m³#10 Nasukarasuyama: 7.1 µg/m³#9 Tochigi: 7.8 µg/m³#7 Yaita: 7.9 µg/m³#8 Kanuma: 7.9 µg/m³#6 Mooka: 8.0 µg/m³#5 Kaminokawa: 8.2 µg/m³#4 Utsunomiya: 8.3 µg/m³#3 Sano: 8.6 µg/m³#2 Ashikaga: 8.7 µg/m³#1 Oyama: 9.2 µg/m³
Each dot is a measured city, coloured by its PM2.5; tap a dot to open the city.
← Mooka 0% 0.75%0
Every measured city in Tochigi, Japan, 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. 1Mooka 0%
  2. 2Sano 0%
  3. 3Oyama 0%
  4. 4Ashikaga 0%
  5. 5Utsunomiya 0%
  6. 6Kaminokawa 0%
  7. 7Yaita 0%
  8. 7Kanuma 0%
  9. 9Tochigi 0%
  10. 10Nasukarasuyamalast full day 30 Sept 0%
  11. 11Imaichi 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

Estimated: cities without a monitor

Tochigi cities we can't measure, with model estimates for the last 7 days. Listed by population, not ranked: estimates aren't precise enough to rank. Model estimates from the Copernicus Atmosphere Monitoring Service (CAMS), adjusted to measured cities nearby where there are any. Adjusted, a single day lands within ×1.5 of what a monitor would read about two times in three; unadjusted, it can be off by half or double. Treat them as a guide, not a measurement.

City7-day estimateBand
Nikkō≈ 2 µg/m³Good
Ōtawara≈ 4 µg/m³Good
Kuroiso≈ 5 µg/m³Good
Shimotsuke≈ 5 µg/m³Good
Sakura≈ 4 µg/m³Good
Mibu≈ 5 µg/m³Good
Ujiie≈ 4 µg/m³Good
Hōshakuji≈ 4 µg/m³Good
Tanuma≈ 6 µg/m³Good
Mashiko≈ 6 µg/m³Good
Nasu≈ 4 µg/m³Good
Karasuyama≈ 4 µg/m³Good
Fujioka≈ 5 µg/m³Good
Ogawa≈ 4 µg/m³Good

Bad-air episodes in Tochigi

Times when many cities around here had PM2.5 at twice their usual or more on the same days.

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SmogRank, most polluted cities in Tochigi, Japan, PM2.5, this year to 6 Oct 2026, 22:00 UTC, smogrank.com/jp/region/tochigi?w=year.

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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.

Updated 2026-10-06 22:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index.