Air pollution levels in Chiang Mai rising

Click the button to check the Chiang Mai pollution levels TODAY! It’s getting to that time of year again when the pollution levels in Chiang Mai start climbing to dangerous levels. This happens every year towards the end of the dry season, between February and April and is largely attributable to slash-and-burn farming methods. Last year the pollution levels got so high that literally thousands of people across Chiang Mai province were admitted to hospital with various respiratory illnesses – including Tina – and the government released a 24 hour emergency number for reporting the fires. You can view the pollution levels in Chiang Mai between 1998 and the present day by clicking on the button above.


PM10 – small but deadly particles

One of the measurements to look for is the PM10 (PM-10) level. This indicates the density of very small particulate matter in the air (particulate matter less than 10 microns in diameter in a cubic metre of air). These particles are too tiny to see – five particles would fit across a strand of human hair – but they can be deadly. As an illustration of how dangerous these particles can be, the number of people in a seemingly ‘clean’ country such as New Zealand who die early from pollution caused by traffic is similar to the number killed in road accidents each year.

These small particles of pollution in the air come from sources such as waste burning, wood burners, car exhausts and industry. They can cause serious health problems, such as making breathing problems like asthma and bronchitis worse. They can exacerbate heart problems, and are thought to be one of the catalysts for throat & lung cancer.

In London, the United States and the European Union as a whole it is considered a serious pollution ‘episode’ if the PM-10 level exceeds 50 – see the London Air Quality Network website.

For some reason, the Thai Pollution Control Department has set the ‘safe level’ to be anything less than a PM-10 of 120. Just to illustrate how high the levels can get to in Chiang Mai, on 14th March 2007 PM-10 levels reached 303.9 – catastrophically high by any standards.

By way of a comparison, the World Health Organisation came up with weighted list of average PM10 concentrations in residential areas of cities larger than 100,000 throughout the world, and the averages were as follows:

A selection of these is as follows:

  • China – 87
  • Denmark – 23
  • France – 15
  • Germany – 22
  • Greece – 47
  • Indonesia – 102
  • Iraq – 178
  • Israel – 52
  • Malaysia – 24
  • Myanmar – 89
  • New Zealand – 16
  • Pakistan – 180
  • Saudi Arabia – 106
  • Spain – 40
  • Sudan – 246
  • Syria – 102
  • Sweden – 13
  • Thailand – 76
  • United Kingdom – 19
  • United States – 25

I decided to work out the daily average for Chiang Mai over the last year from February 2007 to February 2008 and came up with the following:

  • Chiang Mai – 49.85

I then worked out the daily average for March 2007 only and it worked out as the following:

  • Chiang Mai – 161.7

When is the best time to visit Chiang Mai? The answer would depend on the state of your respiratory system – but I’d try to avoid March if possible!

If you’re interested in downloading the Excel spreadsheet with all the international data from the World Bank website – please click here.

25 thoughts on “Air pollution levels in Chiang Mai rising”

  1. Interesting post and quite worrying. When I first came to Thailand many years ago the air in the big cities was considered far worse than it is now, I wonder what the readings back then would have been??

  2. When you think about pollution in Thailand you would typically think about Bangkok or the water pollution from the industry in Samut Prakan, but I wouldn’t have thought that Chiang Mai would be that bad. I had always thought of northern Thailand as a clean area with clear air and water. What an eye opener.

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  4. Hi Doru,

    I’m not convinced that it is actually. I know it is hard to believe but the brief research I did last year on Bangkok’s PM-10 levels showed that Chiang Mai was often worse. I’d be interested in seeing some more accurate comparison figures…

  5. Isn’t it interesting the the Thai government is dumb enough to stop the crap of doing nothing? For a small initial cost, they could plough under the rise fields, pay the farmers a small award, save huge money on local medical costs, and attract more tourists……… Sadly Thai government does nothing because there is no corruption money for them in it. A pity in Thai reality.

  6. Or maybe it’s the corruption money coming from the big land-owners that is actually keeping it going…?

    I see that the pollution is about to explode again, having checked the “pollution control” department’s website just now. Good luck Chiang Mai residents!

  7. I have lived in Chiang Mai for 5 years now and the air quality is getting worse each year. March and April are particularly bad, some schools in Chiang Mai this year have stopped their children from playing outdoors at lunch time due to the problem. The bottom line is that whilst slash and burn is illeagal the police do not enforce it as it is not as lucrative as setting up helmet checks!!!!

  8. I’ve been living in Chiang Mai for 2 years, it is a great city but I think it is insane for me to spend more time here, the air at this moment of the year, March 2009 is really polluted. I am 35 years old, in good health and I like to run, swim, play tennis but now I think it is better for me to stay in my condo with my windows closed, doing exercice outside is close to suicide in March in Chiang Mai. Bad promotion for tourism, just think about the Thai kids and the old people living here, they are all having problems breathing, I wish it could change, but the government and city do nothing, no public transports, over polluting tuc tuc and rot deng, slash and burn every where in the country side. Teach the locals environmental education, and fast…

  9. Whatever the incompetent and toothless local government is doing here about this problem which they all know is going to happen it is not working. Maybe they should talk to people that know how to run a campaign that educates and puts the onus on individuals…has anyone seen a poster, heard or watched a PSA? Unfortunately the Thais are too far up their own ass to approach people that are better than them or do not give backhanders. I am sending my children away as from tomorrow, I am cancelling my sister and her daughter coming over and as soon as I can I am going to take my business and leave this filthy, one star backwater town. Rose of the north? Do not make me laugh

  10. I have lived in Chiang Mai for 3 years now, and have 2 young children. This seems to be the worst year for air pollution, and yet driving back from Hua Hin to Chiang Mai we saw many fires burning – even in the grass verges between the roads (most definitely not farmland). My frustration at the lack of any constructive solution to this continual problem is making me want to move my business elsewhere and remove my family from such an unhealthy environment.

  11. Hi misssarahj,

    Actually March 2007 was worse as the PM-10 level went over 300 and the highest this year has been 215 so far. I’m sure you’re wishing for the rains to come soon – I would be!


  12. was i chaing mai 19 nov-3 dec this year. probably the best months to go if if care about breathing. was there also late feb-early march of this year {2009}. the air quality difference was night and day. the joke that is the corrupt thai government is continuing to ruin this beautiful country. it’s so difficult for we westerners to comprehend the complex nature of the absolutely corrupt police, the do nothing billionaire military generals and the bangkok politicians. most of the thai peope have, in my opinion , been fooled into thinking that thaskin can be their savior…..his billions? yep, stolen from the people. his ability to disrupt any progress in the country is killing the economy. with all their focus on power grabbing and corruption it is no surprise that filthy, murderous air quality is really of no concern. the thai people deserve better.

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  14. I think it would be interesting to see charts of the variously populated cities and how the pollution relates (or doesn’t) relate to population. I know in Houston there are areas that are less populated but have higher pollution levels because of the factories that are there. Anyway– interesting read.

  15. Are there certain parts of Chiangmai that are “better,” than others with regard to air pollution or is all of Chiangmai air polluted to this extent throughout the year?

  16. It’s all pretty bad Carol, but obviously in the city centre, and around the main roads/highways is even worse!

  17. The entire northern region of Thailand is hazardously polluted from late February until the rains come in late April and early May. The pollution is nearly entirely from the burning of fields on the mountainsides, so the rural areas, especially uphill, are far worse. It is one of the bigger reasons I have come to regret moving here from Korat.

  18. Coming to Chiang Mai fr. do dental work at Grace Clinic for 6 weeks starting May 3 – June 16th. How is pollution then and could you give me an idea where would be healthy and convenient place to stay? is Guest house in old town too polluted.Would love to speak on skype to some of the expats living in CM.Thanks

  19. The HUGE problems with pollution in Thailand and especially in the North is a government problem that causes more than 55,000 people to die in Lung and Liver Cancer. In addition there is all those 1000’s in Chiang Mai only that can’t breath. The Thai government is more occupied in catching Thaksin then to deal with real problems such as air pollution even though pollution has no borders so all the neighboring countries might blame each other but in fact they do the same thing to ensure they kill their own people with air pollution.

    It’s time to leave even though I lived here for 13 years but last year was so bad that I went to France for 3 months just to get my breath back again…

  20. This situation isn’t new at all but has changed. I’m going on my 31st year here. Back then it was burning fields and organic debre to clear fields and so forth. It still was bad but most of the burning was organic. Today you have an exploding population and cars hitting the roads by the thousands. You could actually drive down the roads years ago and view the scenery but that type of driving could get you killed on todays roads.

    The real issue in my mind is the huge volume of trash being burned. The fact is that Chiangmai does have regulations on burning but they aren’t enforced. What makes it even more difficult is what to do with the collected trash. Yes, part of the problem is that laws aren’t enforced but when the majority of the population refuses to obey the regulations you have a problem. Case in point is the helmet law!

    I have seen it much worse than now but being a biker I hate ridding through the stuff. The solution will have to be better enforcement and a campaign to teach people not to burn, better trash removable by authorities and lastly TEACH PEOPLE ABOUT COMPOST.

    One last point was someone stating that authorities should shut down rice farming and pay the farmers a fee. Look, being an American we DON’T need more failed handouts. All I can suggest right now is to pray for rain or a good wind to blow this out of the valley. I’ve seen both work effectively over the years. So… don’t take too many deep breaths until monsoons arrive.

  21. Many visitors and even locals seen to be unaware of the dreadful air quality in the north of Thailand.
    If you like to stay indoors, in air-con or your car, you won’t notice the pollution. If you like the great outdoors; you will quickly change from being a fitness freak to a gasping invalid!
    Where I used to live near Mae Rim, there is the additional problem from villagers that burn virtually everything,and that sends shards of wood/trash smoke deep into your lungs.
    Don’t hesitate! It’s your health at stake! Move far away!

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