Chiang Mai Air Pollution

Posted by on February 27, 2011 in General / ทั่วไป, Pollution / มลภาวะ | 14 comments

That time of the year is upon us once again, the time where Chiang Mai and the surrounding provinces become a dangerous place to live and breathe.

For the lucky few, it’s time to pack up your bags and leave Chiang Mai for a few months, for most it’s the time where breathing becomes difficult, the smog becomes unbearable and the air quality in Chiang Mai reaches hazardous levels.

To help keep you up-to-date and to plan your days, we have added a new page for users to check the latest official air quality figures from Chiang Mai and selected locations across Thailand – Air Pollution in Chiang Mai, Thailand in a quick and simple way. An example of what you can expect to find can be seen here.

Current Air Pollution Levels in Chiang Mai


Air Quality Index (AQI)

Find out more: Air Pollution in Chiang Mai, Thailand

Levels Explained

The above colour zones; Green, Yellow and Red zones have been calculated as follows.


The World Health Organization (WHO) 2005 air quality guidelines were used. This report sets a recommended limit of 50 µg/m3 in a 24-hour period and this has been presented in green. In order to help countries like Thailand to reduce their PM10 levels, the WHO published interim levels for which they have 3. The yellow area therefore represents interim level 3 which sets a limit of 75 µg/m3 in a 24-hour period. Anything above this is displayed in red which indicates a unhealthy air quality level.

PM-10 Level Pollution Level Colour
0-50 Low / Good Green
50-75 Medium / Moderate Yellow
75+ High / Unhealthy Red
Air Quality Index (AQI)

Each country around the world has it’s own ‘Air Quality Index’ or AQI guidelines and terminology can differ for example some countries call this measurement the ‘Air Pollution Index’ API (see Wikipedia entry). This monitors a number of components including sulfur dioxide (SO2), nitrogen dioxide (NO2), suspended particulates (PM10), carbon monoxide (CO), and ozone (O3). Thailand too has it’s own formula for calculating their AQI level (see PCD explanation), which has been used here.

AQI Level Pollution Level Colour
0-50 Low / Good Green
50-100 Medium / Moderate Yellow
100+ High / Unhealthy Red

What can we do to help?

Every year there is much talk about this major air quality issue, which usually includes many complaining about those who clear land through burning, the large increase in cars and trucks on the reads and the continuing development of green areas turning into concerete jungles.

In the past, lots of pressure has been put on local government and some positive action has been taken, for example the setup of a helpline to report illegal burning saw residents call in their masses.

Unfortunately the measures are only having a mild effect and as soon as levels return to “normal”, it’s all but forgotten for another year. More needs to be done, but what?

You can help

This website is lucky enough to receive a good number of visitors everyday, each of whom cares for Chiang Mai and is concerned for it’s welfare, especially when it comes to the rise in air pollution levels. We each have different skills and experience that enable us to suggest real ways to improve the situation.

We’d like to call on all of you now to get your thoughts on air quality in Chiang Mai:

  • What do you think should be done?
  • What measures should be put in place?
  • What should local and national government be doing?
  • How should local communities help?
  • What can the expat community do to help?
  • As a growing Chiang Mai community ourselves, what can we/should we do to help?

Please go to our forum now, take part in the discussion and lets work together to make a difference:

Forum Post: Air Pollution: What can we do about it?


  1. Thanks for the meters Alan. A closer look however shows that the meter for PM10 in Chiang Mai points to less than 80 i.e. the yellow warning zone, not in the pink danger area while the figure is over 91.3.

    Also the WHO danger level is et at 50 ppm while the official Thai standard is 120 ppm. I raised this with the head of pollution control for ChaingMai at big public meeting recently and he gave a long convuloted answerI could not follow except that he did not accept my contention that the government lies to the people about the danger level.

    Others may be able to elaborate.

  2. Hi Ricky, Thanks for the feedback.

    I have updated the dials/meters to display the actual numbers more accurately. Also, I have added an explanation on the levels and their associated colours. above and on the page itself for clarification.

    Any further feedback on these levels are welcomed.

  3. Thank you for updates.

  4. Do you think that suggesting someone is lying is a good way to win them over Ricky?

  5. I hope this year the smog is not so bad.

  6. Dr Prasak writes hoping this year will be better than last. Well the answer can be found by looking at the PCD website which has daily figures across Thailand dating back some 8 years.

    Chiang Mai has two recording stations. Uparaat is in the old city beside the school of the same name and readings are usually some 20% higher here than at the Sala Glaang on the Mae Rim road.

    Last year in mid March the pollution was very dangerous with PM10 around 200 ppm. Now following recent rains we have the cleanest air imaginable.

  7. Note about WHO:
    Dr Beat Richter, the famous pediatrician from Switzerland, who has set up hospitals for children in Cambodia gives a talk every Saturday in Siem Reap.
    He continues to make scathing attacks on the WHO which has a policy in the Doctor’s words of “promoting the killing of children”.
    He says the WHO has a policy that medical care should be at a level commensurate with the level of economic development of a country. That means sub-standard hospital laborities, cheap ( often fake & deadly ) drugs etc etc.
    Surely the lax air quality standards the WHO promote for non-first world countries amount to the same and provide a convenient way out for those Thai bureaucrats who care not for the people’s health.
    The PCD appears to be in this category, in sharp contrast to the Health Ministry which has successfully fought big pharma and brought cheap life saving drugs to suffers of AIDS and heart disease.

  8. Today – 14th Jan 2012 I looked at the pollution meters above and notice they are stuck on readings for 15th April 2010. i.e. 86.3 PM10 & 95 for AQI. Yesterdays readings at Chiang Mai are PM10 50.9 $ AQI 57. These should both plummet as we have had morning rain.

    We need to fix this and I suggest the meters, reduced in size appear at the top corner of the login page.

  9. Am on the way to see and setup our new home. However we can not stay because of pollution. I have health issues do not neEd respertory too. Why the Thai’s do not finally fix this do not understand. This place is so nice except!

  10. Excure spelling from my tablet!

  11. Where can I get cuTrent pollution info.? We are now here and will stay in house as much as possible.

  12. Thank you for the figures. I think that Thais are “pyromaniacs”! I fled Chiang Mai because of the ill-effects on my respiratory system. All around our property Thais were burning trash, vegetable waste and rice straw..
    Last week I visited my wife’s province of Buri Ram. We stayed in a new motel, and it was excellent value. However, as soon as I stepped out of the motel, there was once again, the ubiquitous smell of wood smoke! All day and every day!
    Amazing Thailand!

    • We love Chaing Mai but have stopped visiting because of air pollution. We spend Winters in Hua Hin instead. I prefer CM in lots of ways but the pollution was unbearable. When (if) it improves we will be abck but not before.

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