Chiang Mai Air Quality
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Is Chiang Mai Habitable by Humans?
Given its famed air pollution levels, is Chiang Mai habitable by humans? I’ll let you read the below and answer the question for yourself.
All urban air is ‘dangerous’ to some degree: civilisation produces air pollutants, and these damage health. However for a significant portion of the year Chiang Mai’s air is more polluted than that of most cities. This
is because of the high level of burning around the city and beyond, and the northwestern Suthep Range, which blocks the northwesterly and southeasterly winds – winds which would otherwise wash out air pollution – during the cool and rainy
seasons respectively. In addition, a drier dry season in the north means there is less rain to settle pollutants.
Thus, according to one study, in 6 of the 7 categories of air pollution measured in both cities, Chiang Mai had higher concentrations than Bangkok – in most cases far higher concentrations.
More specifically, Chiang Mai’s level of particulates of less than 10 microns (<PM10s – the small particles from burning grass and leaves, and from cooking fires) is usually higher than most other cities in Thailand, including
Because of their size, the <PM10s more readily lodge in the lungs. They carry a potent carcinogen – polycydic aromatic hydrocarbons. These hydrocarbons also cause more severe attacks in asthmatics and heart disease patients.
In 1999, 45% of Chiang Mai residents suffered from respiratory problems, according to Duangchan Charoenmuang, who has long studied Chiang Mai’s air at the Urban Development Institute Foundation.
As for ultra-small particles – the <PM2.5s – an informal, one-day measurement taken by the Unit for Social and Environmental Research found them to be double the US EPA standard. “The effects of breathing air with
a high <PM 2.5 concentration,” says the Unit’s Po Garden, “can include premature death, increased respiratory symptoms and disease, chronic bronchitis, and decreased lung function particularly in children and individuals
The broader Air Quality Index (AQI) is a measure of most known air pollutants. The AQI is frequently elevated above dangerous levels in Chiang Mai, on and off, for several months of the year – usually the January-March ‘burning
season’, but frequently longer. The city’s AQI readings are more often than not higher than those of other Thai cities including Bangkok.
Some of Chiang Mai’s smog is carbon monoxide, nitrogen oxide and sulphur dioxide from industrial and vehicle emissions and cooking fires; and dust from building projects. The levels vary across the municipality – e.g. they’re
much higher at Wararot Market and in Thapae Road.
But most of the ‘smog’ is smoke, and this comes from the deliberate burning of crops and other vegetation, and of forests (often by villagers to trigger the growth of wild ‘throb’ mushrooms, or by poachers to flush
out game); and also from non-deliberate forest and grass fires. These smoke sources are local (Chiang Mai province), regional (northern Thailand) and international (Burma and Laos; but also the ‘Asian Brown Cloud’ stretching from
eastern China through Southeast Asia to Pakistan). No-one knows proportionally how much smoke comes from each area.
(As lowland agriculturalists in the north allegedly only burn selectively, and because so many forest fires are raging in the highlands – many deliberately lit – the current theory is that these highland forest fires – coupled with
an abnormal cold front from China that is trapping haze in the northern valleys – are the prime source of Chiang Mai’s recent pall of smoke. However there is a certain capacity for denial and misattribution of blame in Thai officialdom,
so this theory needs to be taken with a grain of salt for the moment.)
In the short term Chiang Mai’s smoke gives residents coughs, headaches, sore throats, red, streaming eyes, sneezing fits and more serious bronchial illnesses. It caused dozens of heart attacks in 2007.
In 2003 there were 704,800 hospital cases of respiratory disease recorded in Chiang Mai province – roughly twice that of ten years earlier. Dr Duangchan Apawatcharut Jaroenmuang, head of the Chiang Mai-Lamphun Air Pollution Control
Project, states that patients with general respiratory diseases in Chiang Mai outnumber those in Bangkok.
Over the three days to March 20, the number of respiratory patients in Mae Hong Son rose from 416 to 3,541; in Chiang Rai, from 1,780 to 11,148; and in Chiang Mai from 1,370 to 4,514.
In the longer term, Chiang Mai’s smoke raises the rates of lung cancer and other chronic or fatal ailments. Chiang Mai has the second-highest lung cancer rates in the world, according to Prof Sumittra Thongprasert from the Medical
Ecology Department of Chiang Mai University – and higher than any other region of Thailand. The city’s 139 lung cancer cases per 100,000 population is almost 6 times the world average.
An academic study, and a separate news report citing an academic expert, both claim that Chiang Mai, despite its vastly smaller population, has a higher number of lung cancer patients than Bangkok.
http://www.nationmultimedia.com/2007/03/02/national/national_30028253.php and http://www.chiangmainews.com/indepth/details.php?id=625
Other studies have found Chiang Mai’s ‘total suspended particulate’ (TSP) concentrations to be higher than those of Bangkok, Hong Kong and Ho Chi Minh City.
The Public Health Bill of 1992 prescribes that any person who violates the bill by burning their garbage “can be imprisoned for up to six months or fined up to 10,000 baht or both, and will be fined 5,000 baht each day if they continue
polluting the environment”.
But the failure of Chiang Mai’s provincial government to attack the problem of air pollution – or even recognise it – has been close to absolute, recent sabre-rattling notwithstanding. Activists and academic experts have
been hammering away at the government for nearly a decade, to little avail.
The above-cited Dr Charoenmuang, who has spent a number of years studying air pollution in Chiang Mai, and who has discussed the problem with the Mayor among other civic leaders, believes the city authorities have no intention of doing anything
about the problem. Dr Charoenmuang believes politicians are afraid that publicly acting against air pollution might lose the city tourists; but more generally she adds:
“Frankly they are just not clever enough to combat such a vast problem.”
Chiang Mai City Clerk Ken Santitham has commented: “I think that the academics exaggerate… Our air problems are not that severe.” Regarding the action taken to date, Santitham states: “I think that our record has
The City Clerk employs an environment department of one. This employee, Rongrong Duriyapunt, takes a different view: she believes her department’s budget (400,000 baht) is far too small to achieve anything much.
The Thai media are on the case, but are credulous and prone to print wild inaccuracies. The Bangkok Post, at the height of the recent emergency, reported straight-faced a government claim that a major source of the smoke was Korean barbeque
No media outlet has yet asked why no fire-starters have been charged, fined or gaoled; or whether there is any science behind the government-ordered practice of spraying water out of planes, or having fire trucks hose the streets to ‘raise
humidity and induce rain’. No Thai reporter has answered for us the $64,000 question: exactly where does the smoke come from?
A Chiang Mai resident who relies on media reports to learn the truth about the air he is breathing and what it is doing to his health will only gain partial information, and some wrong information.
In January-March – the same three-month period that firebugs were not arrested, fires were not systematically fought, and Korean restaurants were being ordered to douse their barbeques – www.thaivisa.com posters reported deliberately
lit fires all over the north of Thailand. Satellite fire maps showed more than 4000 fires throughout the north in the first half of March.
More than half the time, Chiang Mai’s dangerous levels of air pollution begin in January and end late March or early April. However they have begun as early as August and ended as late as late June.
It’s not clear if the smoke problem is getting worse – 1999 had more ‘dangerous’ <PM10 days than the present year, at least so far – but Chiang Mai’s mid-March 2007 AQI reading of 180 was the highest
since records began.
These are the number of days per year <PM10s were above the safe maximum of 120, in Chiang Mai, 1999 to 2007:
[2003: records missing]
2007: 25 (to Mar 25)
(Includes the tail end of the previous year, to keep seasons together. Also, 2007 is not over and there will probably be worse to come.)
4 bad years out of 8 suggests a 2:1 probability of getting a bad year in any given year. But even if there were two or three ‘good’ years in a row, averages assert themselves in time: a Chiang Mai resident will inevitably end
up with a higher bodily load of carcinogens and general pollutants than residents of other Thai cities, and of most other places in the world.
We don’t need to guess about this, or extrapolate from the daily pollution readings: it is borne out by the city’s extraordinary lung cancer and respiratory illness rates.
In a nutshell, the Chiang Mai resident faces:
• two of Thailand’s most entrenched cultures – rural burning and government apathy
• no concrete proposal to change either (talk notwithstanding)
• on average, dangerously high pollution levels, on-off, through about 25% of every second year
• an elevated probability of lung cancer, respiratory ailments and other illnesses (children and the elderly being the most vulnerable)
• frequent media misinformation as to the causes and extent of the problem, and a failure to identify wrongdoers
In light of the above, does one keep one’s self and one’s family in northern Thailand, or does one move to somewhere like Surat Thani, which – from a quick scan of ten years of data – has never had a day where
<PM10s were above the safe maximum?
That’s up to you.
1. The above information is taken from publicly accessible government data, academic studies, and media reports which quoted air pollution experts. (Various dates going back about 8 years.) Apart from the raw government pollution data I studied
directly, which I’m fairly sure is accurate, I can only assume the rest is accurate. As no-one is paying me to do this, I haven’t verified most of the claims and quotes with primary sources.
2. The above is written for the ‘average’ resident, who cannot afford to live in Chiang Mai part of the year (the non-burning part) and move elsewhere when the smog mounts.
3. The worst air pollution years previous to this one were 1999 and 2004. If 2007 follows the 2004 pattern, the serious pollution will finish in the next couple of weeks. If 2007 follows the 1999 pattern, we will have dangerous levels of
air pollution through till late June.
4. A superb Thai government website where you can monitor air pollution anywhere in Thailand, view past data, bring up tables and graphs, etc, is:
Very interesting and real food for thought. Now we can see why our favourite Chiang Mai resident, or at least former Chiang Mai resident, a certain Mr. Kelly, departed the northern capital for the seaside.