SmogRank / World / Thailand / Chiang Rai / February 2025

Most polluted cities in Chiang Rai, Thailand, February 2025

3 cities in Chiang Rai, Thailand ranked by their average PM2.5 over the 28 days. Worst: Mae Sai at 39.8 µg/m³, #98 of 2,574 cities in the world. Cleanest: Chiang Khong at 23.0. 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.

← Mae Sai 79% 70%0
Every city in Chiang Rai, Thailand ranked for February 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. 1Mae Sai
    79%
  2. 2Chiang Rai
    25%
  3. 3Chiang Khong
    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

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SmogRank, most polluted cities in Chiang Rai, Thailand, PM2.5, February 2025, smogrank.com/th/region/chiang-rai/history/2025-02 (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.