Thailand Air Quality
Live PM2.5 and US AQI readings for Thailand's main tourist cities, plus a guide to the North's annual burning season and how to plan around it. See also the Bangkok weather forecast.
Bangkok
24
US AQI
GoodPM2.5: 3.4 µg/m³ · PM10: 4 µg/m³
Chiang Mai
39
US AQI
GoodPM2.5: 1.8 µg/m³ · PM10: 1.9 µg/m³
Phuket
51
US AQI
ModeratePM2.5: 7.4 µg/m³ · PM10: 12.2 µg/m³
Pattaya
20
US AQI
GoodPM2.5: 1.4 µg/m³ · PM10: 2.4 µg/m³
Koh Samui
38
US AQI
GoodPM2.5: 5.8 µg/m³ · PM10: 9.3 µg/m³
Krabi
49
US AQI
GoodPM2.5: 6.9 µg/m³ · PM10: 10.8 µg/m³
Hua Hin
19
US AQI
GoodPM2.5: 1.1 µg/m³ · PM10: 2.1 µg/m³
Live data from Open-Meteo, updated Aug 31, 2026, 4:00 AM (Bangkok time). Refreshes roughly every 30 minutes.
EPA Air Quality Index scale
| Band | US AQI | What it means |
|---|---|---|
| Good | 0–50 | Air quality is satisfactory. Enjoy the day outdoors. |
| Moderate | 51–100 | Acceptable for most people. Unusually sensitive groups should watch for symptoms. |
| Unhealthy for Sensitive Groups | 101–150 | Children, older adults and those with respiratory conditions should reduce prolonged outdoor exertion. |
| Unhealthy | 151–200 | Everyone may begin to notice effects. Consider a mask outdoors and shorten outdoor plans. |
| Very Unhealthy | 201–300 | Health alert. Avoid prolonged outdoor exertion; wear an N95 mask if you must go out. |
| Hazardous | 301+ | Emergency conditions. Stay indoors with filtered air where possible. |
What PM2.5 means for travelers
PM2.5 refers to fine particulate matter smaller than 2.5 micrometers — small enough to lodge deep in the lungs and enter the bloodstream. It comes from vehicle exhaust, industry, and — in Thailand's case — large-scale agricultural and forest burning. Short visits at moderate levels are rarely a health concern for healthy adults, but travelers with asthma, other respiratory conditions, young children, or older adults should pay closer attention, especially in Bangkok during hazy spells and in the North during burning season.
Thailand's burning season, month by month
Nov–Jan
Generally clean
Northeast monsoon clears the air across most of the country — one of the best windows to visit anywhere, including Chiang Mai.
Feb–Apr
Burning season (North)
Agricultural and forest burning across northern Thailand and neighboring countries pushes PM2.5 up, worst in Chiang Mai, Chiang Rai and Mae Hong Son. Bangkok can see haze too, but usually milder.
May–Oct
Rainy season, cleaner air
Monsoon rains wash particulates out of the air across the country — reliably good air quality even in the North.
Practical tips
- Check before you plan outdoor time. On days above US AQI 100, shift strenuous activity — hiking, cycling, long walks — to earlier in the day or move it indoors.
- Pack an N95 or KN95 mask if you're visiting Chiang Mai, Chiang Rai or Mae Hong Son between February and April. Cloth and surgical masks don't filter PM2.5 effectively.
- Ask about air purifiers when booking hotels in the North during burning season — many properties now offer HEPA purifiers in rooms on request.
- Have a backup itinerary. Bangkok, the islands and the South are usually far less affected, so a bad-air week in the North is a good excuse to head for the coast.
Frequently asked questions
Is Bangkok's air quality bad?
Bangkok's air quality is usually moderate, with occasional spikes into unhealthy territory during the dry season (roughly December–March) when traffic exhaust and regional burning combine with still air. Outside those months it's typically fine for outdoor activity.
When is burning season in Chiang Mai?
Chiang Mai and the wider North see the worst air quality from around February to April, when farmers clear fields and forest before the rains. PM2.5 levels can reach 'Unhealthy' or 'Very Unhealthy' on the worst days, especially in March.
Is it safe to visit Thailand during burning season?
Yes, with some planning. The islands and Bangkok are far less affected than the North. If you're set on Chiang Mai or Chiang Rai in Feb–Apr, check daily readings, pack an N95 mask, keep outdoor time shorter on bad days, and consider a hotel with air purification.
What is a 'good' PM2.5 level?
The US EPA considers PM2.5 under about 12 µg/m³ (US AQI 0–50) 'Good.' Thailand's own standard is more lenient. This page uses the US AQI scale so readings are comparable to what you'd see for any other city worldwide.
How often is this page updated?
Readings come live from Open-Meteo's Air Quality API and refresh roughly every 30 minutes.
Do I need a mask in Bangkok?
Most days, no. On days when the US AQI climbs above 100 (Moderate to Unhealthy for Sensitive Groups), an N95 or KN95 mask outdoors — and limiting strenuous exercise — is a sensible precaution, especially for children, older travelers, or anyone with asthma.