High PM2.5 levels make Chiang Mai world's 3rd worst polluted city
Chiang Mai was ranked for a time on Wednesday as the third-worst major city in the world for air quality due to high levels of PM2.5 ultrafine dust, according to the Swiss firm IQAir.
It reported that Chiang Mai’s Air Quality Index was 166 on Wednesday morning, which was in the dangerous or red zone. It was ranked third after Kolkata in India and Cairo in Egypt.
But by noon, Chiang Mai’s AQI fell to 158 and its rank dropped to No 5 after Kolkata (165 AQI), Kathmandu, Nepal (162 AQI), Tehran, Iran (159 AQI), and Hanoi, Vietnam (158 AQI).
Meanwhile, the Geo-Informatics and Space Technology Development Agency (GISTDA) in Bangkok reported that as of 8am Wednesday, the five provinces with the highest levels of fine particulate matter were:
- Nan, 82.2 micrograms per cubic metre
- Mae Hong Son, 80 μg/m3
- Lamphun, 78.9 μg/m3
- Lampang, 78.7 μg/m3
- Chiang Mai, 77 μg/m3.
