Smoke Pollution Makes March the Worst Month to Visit Chiang Mai and Northern Thailand


You would have to be crazy to intentionally plan a trip to Chiang Mai during the month of March. Your chances for having your trip ruined by hazardous levels of air pollution are significantly increased. In general, I would not recommend anyone plan to visit Northern Thailand during the two month period from the middle of February to the middle of April. Your chances of encountering unbreathable air are just too high.

Just how bad is it? Look at the two photos below. They were taken from my apartment balcony looking west towards Doi Suthep, Chiang Mai’s famous mountain. The first picture was taken on February 23, 2013. Now, the smoke and haze problem can be bad at the end of February, as well, which is why I think I took this picture. We had gotten some unseasonable rain the night before, and I was surprised how clear the air was. Anyways, this is what the view of the mountain should look like on a clear day:


Doi Suthep on a clear day

And this is a picture I took this morning, March 25, 2013:


Where did the mountain go?

Anyone with eyes can see that this is not healthy air to be breathing. To see how bad it really is, we also need to look at the data for pollution particles in the air. At the time the above picture was taken, Yupparaj Wittayalai School, which is located almost exactly in the middle of the city of Chiang Mai, was reporting a moving 24 hour average of 202 micrograms per cubic meter of PM10 particles. These are the particles less than 10 microns in diameter, which can easily lodge within lung tissue and cause many health problems. A PM10 count above 120 is considered unsafe. Here is a graph for the month of March showing the PM10 counts:

Chiang Mai PM10 readings for March 2013

Chiang Mai PM10 readings for March 2013

You’ll notice that the PM10 count has consistently risen above unsafe levels since March 14, and it has only gotten worse as the month progressed. If you think these levels are bad, the air pollution in the nearby city of Mae Hong Son is just downright scary. Look at this graph showing the PM10 readings over the past 5 days:

Extremely dangerous air pollution in Mae Hong Son, March 21-25 2013

Extremely dangerous air pollution in Mae Hong Son, March 21-25 2013

Yes, as you can see from the graph, the PM10 levels never dipped below 100 during the 5 day period, and at their worst they shot up over 700! How can we allow this to happen?

What is the cause of this smoky haze that appears every year at the same time? To understand it, you have to know about the seasons in Thailand. As part of Southeast Asia affected by the monsoon, Thailand basically has 3 seasons: hot, rainy, and cool. The rainy season lasts from about June to October. It is the time of year when the main rice crop is planted and grows. The cool season is from about November to February, and the hot season is usually March to May. In the northern part of Thailand, the cool and hot seasons are both very dry, with little rain at all. This makes it the perfect time of year to burn stuff.

Some of the burning is undoubtedly the result of naturally occurring forest fires that break out in the hot dry conditions. However, the lion’s share of the smoke pollution is the result of man-made fires. The two main types of fires are agricultural fires and forest fires. The agricultural fires are set by rice farmers in the valleys. After the rice is harvested, there is a lot of material from the old rice stalks that must be cleared in order to prepare the soil for the next season’s planting. The easiest way for farmers to clear their land is to simply set their fields on fire. So this is what they do. This results in huge amounts of smoke polluting the air. It also starts numerous forest fires in the surrounding areas from burning embers that get carried by the wind.

The other type of man-made fire is forest fires that are set by people living in the hills for a number of reasons. They may do it to clear away underbrush as a way to encourage the growth of favorite types of mushrooms. They may do it to flush out wild boar so they can be easily hunted. Or they may do it as slash-and-burn farming to clear away trees from forest land and use it to grow crops.

One other Thai habit that adds to all the air pollution is the tendency to sweep up dry leaves into a pile and then set it on fire. No matter where you go in the country, this seems like the most common and accepted way to dispose of dry leaves that fall on your property.

The result is thousands of people every year showing up at area hospitals with complaints of eye infections, chest pain, burning throats and sinuses, and heart conditions. So what is the government doing about it? Not much, really. Every year they seem to talk a lot about the problem, but never actually get anything done. Instead of trying to get farmers to stop burning they encourage them to burn at controlled intervals or other such nonsense. And for the times when they do actually put a complete ban on burning in place, there is no enforcement to speak of. Much of the burning takes place at night because people know it’s easier to get away with lighting fires at that time.

Has this yearly problem hurt the number of tourist arrivals? Not this year. But I think that’s because of the recent explosion in independent tourists coming from China. Last year there was a hit movie in China that took place mostly in Chiang Mai. Since then, you can’t tun around in Chaing Mai without bumping into a Chinese tourist…they’re everywhere. But I feel sorry for them if they came here at the end of March without doing some research on the yearly pollution problem beforehand. All the tourists going up to the temple on top of Doi Suthep must be pretty disappointed by the view. If I can’t see the mountain from the city, there’s no way they can see the city from the mountain.

So should you avoid traveling to Chiang Mai and Northern Thailand because of this problem? Only if you happen to come to Thailand during mid-Feb to mid-April. If this is the only time you can plan a trip, I’d really recommend you stick to Bangkok and the South. The beaches will be much more enjoyable at this time. However, during the other 10 months out of the year the air quality in Chiang Mai is usually good to excellent. Really, anytime between June and January is much better for taking in the sights of the North.


Smoke Pollution Makes March the Worst Month to Visit Chiang Mai and Northern Thailand — 5 Comments

  1. And this year they have continued into May and there is no end in sight…. We have been dealing with dangerous air quality for 5 months now and moving into our 6th month. 6th May 2016

    • I think December and June are the best months. June has mild weather with many cloudy days and some rain, which can be a refreshing change from constant glaring sunlight. The air is also very clean then, and the trees are all so green. December is good for cooler weather that is dry and usually sunny, but there are also more tourists then.

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