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?