By Pratch Rujivanarom
The North continued to choke in smog, as air pollution level soared in an increasing number of hotspots after the end of the ban on burning.
The level of particulate matter smaller than 2.5 microns (PM2.5) in many provinces of the northern region, especially in Chiang Mai, continued to rise yesterday to 100 microrams per cubic metre of air by 6am, as measured by the Pollution Control Department (PCD).
The Chiang Mai University’s DustBoy app disclosed that by 10am yesterday, all of its PM2.5 monitoring stations had reported harmful level of air pollution, with four reporting a PM2.5 AQI (Air Quality Index) over 300, or hourly PM2.5 level over 250 micrograms – a level considered “very dangerous to all people’s health”. The four stations with a critical red level of PM2.5 AQI were: Debaratana Hospital in Mae Chaem District, which had PM2.5 AQI at 320; San Kamphaeng Hospital (304); Chom Tong Hospital (331), and Chai Prakan Hospital (317).
Another two stations at Chiang Dao Public Heath Office (280) and Chiang Mai Night Bazaar (202) were reported to have orange levels of PM2.5 AQI or “very harmful to health”. DustBoy’s single PM2.5 monitoring station in Chiang Rai – at Mae Fah Luang University – reported a very harmful level of PM2.5, at 219 as of 10am.
All people within the areas of PM2.5 AQI red and orange zones are warned to avoid all outdoor activities, while sensitive groups of people such as children, the elderly or respiratory disease patients should ensure they remain in clean and air-purified rooms.
The prolonged period of haze problem in the North, which dragged on beyond Songkran Festival, was considered to have been caused by the increasing number of hotspots after the burning ban was ended in most provinces on April 20.
This speculation was confirmed as accurate by data on hotspots from a NOAA satellite, according to the Asean Specialised Meteorological Centre (ASMC). The satellite imagery tracked the increase in the number of hotspots in Thailand increasing from one on April 20 (the final date of the burning ban in Chiang Mai and Lamphun) to 39 the next day and 82 on April 22.
According to the previous records of northern haze, the smog season normally ended after Songkran Festival in mid-April, due to wetter condition from summer storms and the approaching rainy season.
With worsening air pollution lingering longer than expectation, PCD has issued a warning for all related agencies and local authorities in the North to continue to control open burning in their area, especially roadside burning and lighting of fires near or on forestland.
PCD also asked that people refrain from outdoor burning of garbage and leftover materials on their farms to help lower the amount of pollution in the air. It also recommended that people with sensitivity to air pollution wear facemasks at all time when outside.
The department also warned that the air pollution was likely to continue, and even intensify, today. People should strictly avoid burning especially during the night and morning during this period.
Chiang Mai University’s Climate Change Data Centre (CCDC) also reported that NASA, GISTDA, and ASMC satellite data has similarly indicated that the transboundary haze from hotspots outside the country was intensifying the smog problem in Thailand’s North.
CCDC concluded that a large number of hotspots have been documented in Myanmar during the past weekend, with hotspot pollution counts reaching as high as 210, according to ASMC data. The smog from these hotspots is tending to drift toward Thailand due to the westerly wind, said the CCDC.