Stories tagged with quality
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Rain soaks up bad air
Fears that Chiang Mai might again suffer hazardous air quality conditions this season have been unfounded, and recent early season rains have brought the PM10 levels down way below the critical level.
Thunder showers through the week in the late afternoon, and humid conditions have served to mitigate the effects of chronic burning that occurs at this point in the dry season, creating hazy conditions and filling the air with harmful particles. Climate conditions have also been more favourable than 2007 when the province was blighted with hazardous air conditions for more than a month. So far, only a eight days in March this year have produced conditions where the PM10 index is above the 120 level considered dangerous to respiration.
Over the last weekend of March the index had fallen below 80, and the mountains were again visible (a quick indicator), but in Mae Hong Son province, where the burning is out of control, the index remained well above 100.
Local tourist business have complained the bookings are down 20%, as the negative publicity of the previous year has taken its toll on tourism confidence in the Northern region. However a widely initiated campaign to educate locals and discourage burning has helped spread the word among villagers and city dweller alike.
Rain in early April is unusual, and has been a welcome respite from the high temperatures being experienced. The King has also taken a personal interest in the problem this year and has instructed rain-making exercises to be conducted, helping ease the problem.
Pollution control department readings
Posted by: Andrew on 31 Mar 2008, 04:29 -
Bad air returns to Chiang Mai
Habitual burning and stagnant air conditions have brought back the annual smog that blankets Chiang Mai in March each year. So far it hasn’t been quite as bad as 2007, but visibility in the mountains has been poor and the air quality index is approaching unhealthy levels.
Tourism in this Northern city takes a knock for a few weeks in March each year as farmers burn fields or mountain sides, contributing think smoke to the ambient air which at times can be dangerous to breathe. At present measuring stations at the airport and in the old town have yet to record any days were the PM<10 index has topped the critical 120 level. This is a measure of the sub 10 microns in the air, which are able to lodge in the membranes of the lungs.
When the measure of parts per million increases above 120, the air is considered unhealthy to breathe, and during one week last year it topped 300. This was a result of unusual climate conditions where a lack of moisture in the air (to bind the particles) and a lack of wind in the Ping valley exasperated the situation.
Such conditions are not expected this year, but travellers with asthma conditions or young children are advised to avoid the city or spend their time here up in mountain reaches or outside of the valley – which acts as a natural trap. By the end of March the hazard usually passes.
In addition to poor breathable air, the natural beauty of the mountainous north disappears as visibility drops. On Thursday March 6th the PM>10 value was measured at 97, and Doi Suithep mountain was barely visible from the city. However, by contrast the industrial suburb of Bangkok, Samut Prakarn had a measure of 186. Lampang is another Northern area particularly at risk, measuring 140.
Pollution Control Department regional air quality data
Posted by: Andrew on 06 Mar 2008, 06:16