By Chularat Saengpassa
WITH HAZE continuing to choke many northern provinces yesterday, Chiang Mai University’s mobile “Dust Boy” monitors measured “code-red” levels of PM2.5 in several areas of the country’s second city. Code red covers levels above 90 micrograms per cubic metre of the most dangerous airborne particles.
A Dust Boy monitor in Muang district’s Nong Pa Khrang recorded 135mcg of PM2.5 and an Air Quality Index (AQI) level of 245 – far above the safe limit of 100.
Chang Klan showed 97mcg of PM2.5 and an AQI of 207. Chiang Mai University in tambon Mae Hia reported 83mcg of PM2.5 and an AQI of 190.
The Dust Boys are placed at various spots across the city to provide real-time air quality information at the website cmuccdc.org/pm25.
Yesterday’s daily update from the Pollution Control Department (PCD)’s website (air4thai.pcd.go.th) reported levels of PM2.5 in the North of between 32 and 86mcg. The peak was in Mae Mo, Lampang, where the air was polluted by 86mcg (AQI 190), followed by Phra Baht of Lampang’s Muang district and Wiang of Phayao’s Muang district, both at 83mcg (AQI 182).
The PCD readings are a 24-hour average so record lower levels of pollution than “real-time” monitors like the Dust Boys.
PCD reported that its four monitoring stations in Chiang Mai reported PM2.5 levels of 32-55mcg, with Chang Pheuk in Muang district reaching 55mcg.
Mae Hong Son suffers
Mae Hong Son, which has suffered five consecutive days of air pollution above the PM2.5 safe limit, yesterday reported a slightly improved figure at 51mcg (AQI 101).
Mae Hong Son governor Sirirat Chamupakarn said local authorities were practising controlled burning to clear tinderbox areas, which would be replaced by a total ban on outdoor burning from March 1 to April 30.
The governor said tourists continue to visit the province in large numbers despite the haze. Residents of Muang district have complained of eye irritation from particulate dust that has shrouded surrounding mountains in a grey veil. Many are asking why dust levels visible to the naked eye do not translate to a higher PM2.5 reading.
The Geo-Informatics and Space Technology Centre Northern Region reports that the MODIS images produced by Nasa’s Terra satellite images showed particle dust blanketing eight northern provinces as of 10.37am yesterday.
The centre said the haze was particularly dense over Chiang Mai, Lamphun, Lampang, Phayao, Phrae and Nan.
Meanwhile, the Geo-Informatics and Space Technology Development Agency’s fire monitoring system (fire.gistda.or.th/) reported that a MODIS image on Monday had shown 160 hot spots in Thailand, with 53 locales in the nine northern provinces. It also showed 121 hot spots in Myanmar, 203 in Cambodia, 62 in Laos and 11 in Vietnam.