The time of year infamously known as Chiang Mai’s smoky season has arrived. Perhaps one of travelers’ biggest worries is planning a trip to northern Thailand and not knowing how bad the air quality is. After living through several of Chiang Mai’s smoky seasons, here’s what you can generally expect during the worst of it and how to handle it.
Chiang Mai’s hot smoky season doesn’t get into full swing until March. However, we’ve noticed the beginnings of haziness as early as January and extending through the end of April.
What Causes Chiang Mai’s Smoky Season?
The smoky season is caused by several different factors, although we can’t say for certain which is the biggest contributor.
It’s well-known that local farmers burn fields and brush to get ready for a new season of crops. We’ve driven past farmland just outside Chiang Mai’s Old City and smoke trails can be easily seen from the road. We’ve also seen smoke wafting up from the hills and nearby mountains. Locals also burn their trash, but that is arguably a year-round thing.
Additionally, it’s hard to miss the dark gray smog spewing from vehicles’ exhaust pipes, particularly from Chiang Mai’s songthaews and tuk tuks. When the high season rolls around between October and February, the increased traffic adds to the air pollution.
Chiang Mai is also surrounded by Doi Suthep, Doi Saket, Doi Inthanon, and Doi Khun Tan. These mountains help to create a valley that traps the dense vehicle smog and crop burning smoke over Chiang Mai.
And not to be forgotten, the last rainstorm passes through Chiang Mai near the end of October. No frequent rain to clean the air means that by the time it’s March, the land and air are dry and dusty.
What to Expect During Chiang Mai’s Smoky Season
Chiang Mai’s smoky season is apparent by its typical robin egg blue skies replaced by a dingy yellow haze, lack of visibility, and a lingering campfire smell in the air. Even nearby hills and buildings can be difficult to see and often disappear entirely on bad days. On the worst days the local mountain, Doi Suthep, cannot be seen. Even the sun is muted to a glowing orange ball in the sky.
The smell of smoke lingers in the air. We smell it in the morning when we first step outside or open our windows. When we go out for the evening or line-dry our laundry, our clothes and hair smell like we’ve been around a bonfire.
We also noticed that many surfaces develop a thin gritty film on them. Often we can see the dust clouds hanging in the air, which were created by passing cars and nearby construction.
Health Effects of Chiang Mai’s Smoky Season
The dust, dirt, and smoke particles contribute to a poor air quality index (AQI). Particles that are smaller than 10 microns in diameter (PM10 or less) are considered to have adverse health effects, particularly PM2.5. Carbon monoxide, nitrogen dioxide, and sulfur dioxide also contribute to AQI levels. Levels constantly swing between 101 (Unhealthy for Sensitive Groups) and 200 (Unhealthy).
Chiang Mai’s AQI levels can be viewed in real-time on AQICN.org, although this site doesn’t show seasonal trends or a yearly comparison. For those who are interested in conveniently monitoring the air quality, there’s also an app called Air4Thai available for Android and Apple smartphones.
In general, the higher the AQI, the hazier it is and the greater toll it can take on your lungs. Some people may also experience sinus trouble. For others, the smog can cause bronchial inflammation, labored breathing, or an asthma attack.
How to Combat Chiang Mai’s Smoky Season
Many people are concerned with the adverse health effects caused by the increased air pollution during Chiang Mai’s smoky season. Luckily, there are a few options to keep you healthy, both indoors and outdoors.
01 Stay Indoors During Peak Hours
Staying indoors during the hottest times in the afternoon will do wonders for most people. Chiang Mai’s smoky season also coincides with some of the hottest temperatures of the year, so we find ourselves preferring to go out in the mornings and evenings anyways. We make sure to keep our windows shut and turn on the fan if we want air circulation in our house.
02 Wear N95 Grade Masks
If the smog is bothersome while you’re outside, wearing face masks with a proper filter grade will protect your lungs and sinuses. Look for masks that specifically advertise a filter grading of at least N95. They should also fit snugly around the nose and mouth with no open gaps on the sides to allow unfiltered air in.
We have purchased masks like this at large department stores such as HomePro or hardware stores featuring 3M products. Masks generally cost around 150 baht (5 USD) each.
These are not the cheap surgical look-a-like masks that can be purchased at 7-Elevens, mini Tescos, or FamilyMarts. Thais wear these thin, white masks during the burning season but they are useless. These masks don’t protect the lungs from the finer particles.
03 Invest in an Indoor Air Purifier
Air conditioning units can filter the air for larger particles such as lint and hair. However, investing in a stand-up air filter for your home or apartment can keep your lungs and sinuses happy indoors. These are designed to trap the smaller particles.
There are many brands on the market. They are generally accessible at major home appliance stores and supercenters such as HomePro. These air purifiers are expensive, but it’s worth the investment for people who are more sensitive to the air quality.
Although we don’t have an indoor air filter, we use a neti pot to clean out our sinuses from time to time. We bought ours from a small pharmacy at Chiang Mai Gate and use it when the dust and smoke make our noses itch. There are different brands and styles of neti pots, but we prefer the squeezable ones to the ones that work off gravity alone.
04 Enjoy Time in Southern Thailand
Otherwise, you can do what we’ve planned to do and vacation in the southern beach regions of Thailand. The crop burnings are so few and far between that they affect the air quality much less. We’ve recommended this to others in the past.
Our Experience with Chiang Mai’s Smoky Season
We first arrived in Chiang Mai in March 2013 right as the burning season was kicking into high gear. At the time the sky was hazy and the air smelled like a campfire but we weren’t overly affected by the dry heat or the smoke at the time. We attributed this to being preoccupied with getting settled into our new apartment and being so excited about moving to Thailand.
Every year since – 2014, 2015, and 2016 – Chiang Mai’s smoky season has seemed to worsen. We did invest in face masks with the proper N95 filter grade. Chris noticed that his sinuses flared up when he didn’t use his mask outside when we were on our motorbike. We also adjusted our schedule and stayed inside between 2pm and 6pm when we thought it was the hottest. We also generally avoided outdoor restaurants and cafés.
It wasn’t until the rain showed up sporadically in April and May that the visibility and air quality improved significantly.
The Bottom Line
Chiang Mai’s smoky season can make you physically uncomfortable and you definitely miss out on the picturesque views. It’s no wonder why tourists are hesitant to visit Chiang Mai during the burning season. Or why locals tend to vacation down south during this time.
We personally do not recommend visiting northern Thailand in February, March, or April. This is especially true if you have breathing problems triggered by air pollution. However, we think most people will enjoy their time here as long as they know the limitations of their own body and use caution when outside. After all, we’re sure almost anyone would be thrilled to spend time in Chiang Mai, smoky season or not!