By The Nation
The Pollution Control Department (PCD) put the level of PM2.5 – airborne particulates 2.5 microns or less in diameter – at 85-93 micrograms per cubic metre of air in Muang Chiang Mai, well above the 50mcg safe limit.
PM10 was at 114-123 micrograms, exceeding the 100mcg safe limit, and the Air Quality Index (AQI) ranged from 188 to 203mcg, double the 100mcg safety threshold.
Three of the PCD’s four air-quality-measuring stations recorded unsafe levels of PM2.5. In the tambon of Suthep it was 85mcg (AQI 188), in Sri Phum 91mcg (AQI 201) and in Chiang Pheuk 93mcg (AQI 203).
The PCD urged people including schoolchildren to refrain from outdoor activities and to wear facemasks outside, while small children and the elderly, pregnant and chronically ill were told to closely monitor their health.
Across Bangkok and five neighbouring provinces, only two areas of the capital had unsafe levels of PM2.5 on Wednesday morning.
One was on Paholyothin Road in Bang Khen district (61mcg) and the other the Thung Song Hong area in Lak Si district (51).
The PCD predicted a rise in PM2.5 for Thursday but expressed confidence that dust-control measures should lessen the severity.