Air quality
Air quality in Chiang Mai today
Updated
Moderate (US AQI 61) Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. Model estimate for Mon, Oct 26, 8:00 am (01:00 UTC).
Live AQI, PM2.5, PM10 and ozone for Chiang Mai, Thailand, with a 48-hour forecast and the best time to be outside.
- US AQI now
- 61 Moderate
- PM2.5
- 18 µg/m³ 1.2× WHO 24-h guideline
- PM10
- 19 µg/m³
- Ozone
- 56 µg/m³
- Dominant pollutant
- PM2.5 sub-index 61
- Best hour today
- 8:00 am AQI 61
- European AQI
- 42
Air quality in Chiang Mai right now
Right now the modelled US Air Quality Index for Chiang Mai, Thailand is 61, which falls in the "Moderate" band (up to 100). Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors.
The index is driven mainly by PM2.5, whose own sub-index is 61. Fine and coarse particles come from traffic, heating, industry, dust and smoke; they build up on calm nights and clear when wind or rain arrives.
PM2.5 is 18 µg/m³, 1.2 times the WHO 24-hour guideline of 15 µg/m³; PM10 is 19 µg/m³ against a guideline of 45; ozone is 56 µg/m³ (below the WHO 8-hour level of 100); nitrogen dioxide is 15 µg/m³ (below the 24-hour guideline of 25).
Also this hour: UV index 1.2, carbon monoxide 676 µg/m³.
NASA FIRMS shows 5 fire hotspots within 300 km in the last day (nearest about 211 km), but particle levels are not elevated enough to point to smoke right now.
Chiang Mai AQI forecast: next 48 hours
Over the next 24 hours the AQI is forecast to range from 61 around Mon 8:00 am to 107 around Mon 5:00 pm, from "Moderate" at best to "Unhealthy for Sensitive Groups" at worst.
The following day is expected to be cleaner, averaging about 62 against 72 for the next 24 hours.
| Local time (Asia/Bangkok) | US AQI | Category | PM2.5 µg/m³ | PM10 µg/m³ | Ozone µg/m³ |
|---|---|---|---|---|---|
| Mon 8:00 am | 61 | Moderate | 18.4 | 19 | 56 |
| Mon 11:00 am | 63 | Moderate | 18 | 18 | 158 |
| Mon 2:00 pm | 65 | Moderate | 16.4 | 17 | 143 |
| Mon 5:00 pm | 107 | Unhealthy for Sensitive Groups | 15.4 | 16 | 113 |
| Mon 8:00 pm | 75 | Moderate | 20.6 | 21 | 54 |
| Mon 11:00 pm | 68 | Moderate | 24.9 | 25 | 27 |
| Tue 2:00 am | 67 | Moderate | 13.4 | 13 | 25 |
| Tue 5:00 am | 66 | Moderate | 15.3 | 15 | 44 |
| Tue 8:00 am | 66 | Moderate | 11.9 | 12 | 76 |
| Tue 11:00 am | 64 | Moderate | 6.6 | 7 | 113 |
| Tue 2:00 pm | 61 | Moderate | 7.4 | 8 | 127 |
| Tue 5:00 pm | 66 | Moderate | 8.9 | 9 | 104 |
| Tue 8:00 pm | 59 | Moderate | 26.7 | 27 | 30 |
| Tue 11:00 pm | 60 | Moderate | 25.6 | 26 | 22 |
| Wed 2:00 am | 60 | Moderate | 18.4 | 19 | 26 |
| Wed 5:00 am | 61 | Moderate | 6.8 | 7 | 25 |
| Wed 8:00 am | 59 | Moderate | 10.9 | 11 | 58 |
Every third hour of the CAMS forecast via Open-Meteo. US AQI uses rolling averages (24 h for particles, 8 h for ozone), so it moves more slowly than the hourly concentrations.
Best time to be outside in Chiang Mai today
Between 6 am and 9 pm local time, the cleanest air today is forecast around 8:00 am (AQI 61, Moderate) and the worst around 5:00 pm (AQI 107). That is a swing of 46 points, so a run or walk around 8:00 am is noticeably better.
Chiang Mai vs the rest of Thailand
Across 24 Thailand cities we track, the average US AQI right now is 55 (Moderate). Chiang Mai at 61 is 6 points worse than average.
For context, the median across 3,556 cities worldwide is 58.
Air quality in cities near Chiang Mai
| City | Distance | US AQI | Category | PM2.5 µg/m³ |
|---|---|---|---|---|
| Mawlamyine | 293 km | 37 | Good | 7 |
| Nay Pyi Taw | 318 km | 67 | Moderate | 24.9 |
| Kyauktan | 370 km | 52 | Moderate | 9.9 |
| Mingala Tangnyunt | 372 km | 52 | Moderate | 9.9 |
| Yangon | 372 km | 52 | Moderate | 9.9 |
| Set Ka Lay | 375 km | 52 | Moderate | 9.9 |
| Hlaingthaya | 377 km | 52 | Moderate | 9.9 |
| Vientiane | 392 km | 62 | Moderate | 7.7 |
Model vs measured
We found no measured PM2.5 sensor cell within 25 km of Chiang Mai, so the numbers on this page are model estimates. Models capture regional pollution well but can miss very local sources such as a busy road or a nearby fire.
Advice for sensitive groups
At 61, most people are fine outdoors. If you are unusually sensitive to PM2.5, keep long or intense workouts to the cleaner hours shown above.
What the US AQI numbers mean
| US AQI | Category | What it means |
|---|---|---|
| 0-50 | Good | Air quality is satisfactory and poses little or no risk; a good time for outdoor activity. |
| 51-100 | Moderate | Acceptable for most people. Unusually sensitive people should consider shortening long or heavy exertion outdoors. |
| 101-150 | Unhealthy for Sensitive Groups | People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors. |
| 151-200 | Unhealthy | Everyone should reduce prolonged or heavy exertion outdoors; sensitive groups should avoid it and keep windows closed. |
| 201-300 | Very Unhealthy | Health alert: everyone should avoid prolonged or heavy exertion outdoors, and sensitive groups should stay indoors. |
| 301-500 | Hazardous | Emergency conditions: everyone should avoid all outdoor physical activity and stay indoors with filtered air if possible. The scale tops out at 500; heavier dust or smoke is shown as 500. |
Values on this page are modelled by CAMS (Copernicus) and served by Open-Meteo; they are estimates for the area around the city centre, not readings from an official monitor.
Nearby cities
More for Chiang Mai
Air quality elsewhere
Data: Open-Meteo Air Quality API, Copernicus Atmosphere Monitoring Service (CAMS), NASA FIRMS.