17 – 23 Sep 2025 · Thailand · Wednesday to Tuesday, UTC+7

Thailand weekly air quality

Modelled US AQI · 8 cities · CAMS via Open-Meteo

44.3Weekly mean modelled AQI · Good

Mean PM2.5: 8.8 µg/m³. Both means cover the selected cities hour by hour. They are not a national average or Thailand’s official index.

-3.5 AQI compared with the previous week’s mean of 47.8.

Highest hourly estimate: 114 in Chiang Mai · 17 Sept, 17:00 GMT+7.

1344 of 1344 city-hours have a modelled AQI. These are estimates for roughly 45 km model grid cells, not monitoring-station measurements. How this report is made

Daily modelled US AQI

Day	Mean AQI	Low–high	Mean PM2.5 (µg/m³)	City-hours
Wed, 17 Sep	50.1Moderate	22–114	11.7	192 / 192
Thu, 18 Sep	48.1Good	15–83	9.6	192 / 192
Fri, 19 Sep	43.1Good	15–79	7.5	192 / 192
Sat, 20 Sep	38.4Good	15–64	7.3	192 / 192
Sun, 21 Sep	41.3Good	18–63	8.7	192 / 192
Mon, 22 Sep	45.9Good	28–63	9.8	192 / 192
Tue, 23 Sep	43.2Good	19–64	6.6	192 / 192

Hourly means (UTC+7)

Each cell averages the selected cities’ modelled AQI for that hour.

Day	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23
Wed	44	44	45	45	46	46	47	48	48	49	50	50	51	51	51	51	54	59	60	57	52	52	52	52
Thu	52	52	51	51	51	51	51	50	50	49	48	48	47	47	46	46	46	46	46	46	45	46	46	46
Fri	46	46	46	45	45	44	44	44	44	43	43	43	43	43	43	43	42	42	42	41	42	42	41	41
Sat	40	39	39	39	39	38	38	38	38	38	38	38	38	38	38	39	39	39	39	39	39	38	38	38
Sun	38	39	38	38	38	39	39	40	40	41	42	42	43	43	43	43	43	43	43	43	43	43	44	44
Mon	45	45	45	45	45	45	45	45	45	45	45	45	45	45	46	46	47	47	48	48	48	48	47	47
Tue	47	46	46	46	45	45	45	44	44	44	43	43	43	43	42	42	42	42	43	42	42	40	40	38

Cities by modelled US AQI

Sorted by weekly mean. Each city is a single model grid cell near its centre.

City	Mean AQI	Peak AQI	Mean PM2.5 (µg/m³)	Hours
Chiang Mai	65.4Moderate	114	16	168 / 168
Khon Kaen	53.2Moderate	62	10.6	168 / 168
Nakhon Ratchasima	49.7Good	75	10.2	168 / 168
Bangkok	46.4Good	67	8.9	168 / 168
Chiang Rai	40.2Good	54	7.3	168 / 168
Phuket	39Good	49	7.1	168 / 168
Hat Yai	37.1Good	46	6.6	168 / 168
Pattaya	23.4Good	34	3.4	168 / 168

City-hours by category

Good: 848

Moderate: 494

Unhealthy for Sensitive Groups: 2

Unhealthy: 0

Very Unhealthy: 0

Hazardous: 0

US AQI scale
AQI	Category
0–50	Good
51–100	Moderate
101–150	Unhealthy for Sensitive Groups
151–200	Unhealthy
201–300	Very Unhealthy
301+	Hazardous

How this report is made

Open-Meteo provides hourly estimates from the Copernicus Atmosphere Monitoring Service (CAMS) global model at roughly 45 km resolution. We use the grid cell nearest each city’s centre. Nearby places may share a cell, and local pollution can differ.

The AQI is the provider’s modelled US AQI across pollutants, one value per city per hour. Weekly, daily and hourly means average those values across the selected cities. PM2.5 is a concentration in µg/m³. These figures use a different basis from the measured PM2.5-derived AQI in the Malaysia and Singapore reports.

Days and hours use UTC+7. The report includes past model hours only, never forecasts. The previous-week comparison appears only when at least 90% of that week’s city-hours are available.

For official local readings and advice, visit Pollution Control Department · Air4Thai. Air-quality data: Open-Meteo and CAMS, licensed under CC BY 4.0. Haze Monitor is independent of these providers and local authorities.

Day	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23
Wed	44	44	45	45	46	46	47	48	48	49	50	50	51	51	51	51	54	59	60	57	52	52	52	52
Thu	52	52	51	51	51	51	51	50	50	49	48	48	47	47	46	46	46	46	46	46	45	46	46	46
Fri	46	46	46	45	45	44	44	44	44	43	43	43	43	43	43	43	42	42	42	41	42	42	41	41
Sat	40	39	39	39	39	38	38	38	38	38	38	38	38	38	38	39	39	39	39	39	39	38	38	38
Sun	38	39	38	38	38	39	39	40	40	41	42	42	43	43	43	43	43	43	43	43	43	43	44	44
Mon	45	45	45	45	45	45	45	45	45	45	45	45	45	45	46	46	47	47	48	48	48	48	47	47
Tue	47	46	46	46	45	45	45	44	44	44	43	43	43	43	42	42	42	42	43	42	42	40	40	38

Day	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23
Wed	44	44	45	45	46	46	47	48	48	49	50	50	51	51	51	51	54	59	60	57	52	52	52	52
Thu	52	52	51	51	51	51	51	50	50	49	48	48	47	47	46	46	46	46	46	46	45	46	46	46
Fri	46	46	46	45	45	44	44	44	44	43	43	43	43	43	43	43	42	42	42	41	42	42	41	41
Sat	40	39	39	39	39	38	38	38	38	38	38	38	38	38	38	39	39	39	39	39	39	38	38	38
Sun	38	39	38	38	38	39	39	40	40	41	42	42	43	43	43	43	43	43	43	43	43	43	44	44
Mon	45	45	45	45	45	45	45	45	45	45	45	45	45	45	46	46	47	47	48	48	48	48	47	47
Tue	47	46	46	46	45	45	45	44	44	44	43	43	43	43	42	42	42	42	43	42	42	40	40	38

Day	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23
Wed	44	44	45	45	46	46	47	48	48	49	50	50	51	51	51	51	54	59	60	57	52	52	52	52
Thu	52	52	51	51	51	51	51	50	50	49	48	48	47	47	46	46	46	46	46	46	45	46	46	46
Fri	46	46	46	45	45	44	44	44	44	43	43	43	43	43	43	43	42	42	42	41	42	42	41	41
Sat	40	39	39	39	39	38	38	38	38	38	38	38	38	38	38	39	39	39	39	39	39	38	38	38
Sun	38	39	38	38	38	39	39	40	40	41	42	42	43	43	43	43	43	43	43	43	43	43	44	44
Mon	45	45	45	45	45	45	45	45	45	45	45	45	45	45	46	46	47	47	48	48	48	48	47	47
Tue	47	46	46	46	45	45	45	44	44	44	43	43	43	43	42	42	42	42	43	42	42	40	40	38