CAMS model • Open-Meteo

Chiang MaiAir quality, PM2.5 and PM10

Check PM2.5 and PM10 particle levels alongside ozone, nitrogen dioxide and other gases. Compare the latest available concentrations with recent days and explore changes in air pollution through the available historical records.

Chiang Mai - latest available concentrations (September 26, 2026, 08:00 local time): PM2.5: 10.1 µg/m³, PM10: 10.2 µg/m³, O₃: 50 µg/m³, NO₂: 16.9 µg/m³, SO₂: 5.2 µg/m³, CO: 719 µg/m³. These are hourly CAMS model values for a point representing the city.

Air quality questions →

1 weather warning in effect for Thailand 🌧️ Heavy rain

Chiang Mai · Air pollutant concentrations

Data time: September 26, 2026 · 08:00 · local time

PM2.5

Fine particles

10.1µg/m³Fair · 1 hour

PM10

Particulate matter

10.2µg/m³Good · 1 hour

O₃

Ozone

50µg/m³Good · 1 hour

NO₂

Nitrogen dioxide

16.9µg/m³Fair · 1 hour

SO₂

Sulphur dioxide

5.2µg/m³Good · 1 hour

Carbon monoxide

719µg/m³

PM2.5 vs PM10 - what is the difference? → · Models and monitoring stations →

DAILY DATA · Chiang Mai

Chiang Mai - air pollution over recent days (2026-08-31 - 2026-09-25)

Concentrations of all available pollutants for this city.

PM2.5Lowest 7.16 2026-09-07Highest 20.83 2026-09-222026-08-31 - 2026-09-25

Scroll the chart or table sideways to see the full period.

Chiang Mai · daily averages · µg/m³
Pollutant	2026-09-25	2026-09-24	2026-09-23	2026-09-22	2026-09-21	2026-09-20	2026-09-19	2026-09-07	2026-09-06	2026-09-05	2026-09-04	2026-09-03	2026-09-02	2026-09-01	2026-08-31
PM2.5	16.46	18.59	18.06	20.83	9.46	10.94	12.09	7.16	14.93	12.13	14.43	12.79	15.5	15.63	11.62
PM10	16.63	18.84	18.2	20.88	9.51	11.39	12.29	7.5	17.18	13.72	18.25	14.18	17.6	17.14	13.04
O₃	67.67	72.96	84.21	73.79	59.58	52.58	62.42	43.79	46.04	40.79	45.08	43.38	38.54	38.38	38.71
NO₂	23.12	24.01	29.98	31.23	18.12	19.85	20.68	12.42	15.93	18.65	16.91	20.58	18.83	22.91	19.32
SO₂	6.57	7.8	14.05	14.57	8.45	7.19	7.27	3.09	3.83	4.82	4.46	5.82	6.33	7.52	5.21
CO	1,865.33	1,501.17	1,399.42	1,250.83	1,031.96	925.75	777.83	837.96	1,032.13	1,818.42	1,832.88	1,378.13	1,251.88	1,410.33	1,091.29

A dot on the chart and a dash in the table indicate missing data. The latest day may be incomplete.

How should I interpret the data and averaging period? →

Open-Meteo / CAMS ↗

AIR QUALITY ARCHIVE · Chiang Mai

Chiang Mai - air pollution history (2015-10 - 2020-05)

Compare monthly particle and gas concentrations in the available archive.

PM10Lowest 21.6 2018-09Highest 118 2016-042015-10 - 2020-05

Scroll the chart or table sideways to see the full period.

Chiang Mai · monthly averages · units shown beside each pollutant
Pollutant	2020-05	2020-04	2020-03	2020-02	2020-01	2019-12	2019-11	2019-10	2019-09	2019-08	2019-07	2019-06	2019-05	2019-04	2019-03	2019-02	2019-01	2018-12	2018-11	2018-10	2018-09	2018-08	2018-07	2018-06	2018-05	2018-04	2018-03	2018-02	2018-01	2017-12	2017-11	2017-10	2017-09	2017-08	2017-07	2017-06	2017-05	2017-04	2017-03	2017-02	2017-01	2016-12	2016-11	2016-10	2016-09	2016-08	2016-07	2016-06	2016-05	2016-04	2016-03	2016-02	2016-01	2015-12	2015-11	2015-10
PM10 µg/m³	30.1	79.8	109	88	69.4	59	47.2	37.3	34.2	28.6	30.4	26.7	49.8	82.6	103	59.6	35.7	29.4	29.7	23.5	21.6	30.9	36.2	38.3	33.2	61.4	85.6	64	39.9	41.5	39.1	38.3	36.7	40.2	36	35.3	47	67.1	69.2	58.9	36.3	38.9	32.4	28.5	27.9	29.7	28.1	24.5	49.5	118	107	82.2	57.8	46.6	35.3	48.3
NO₂ (ppm)	—	—	0.0218	0.0261	0.0253	0.0212	0.0158	0.0107	0.00923	0.00903	0.00642	0.0077	0.014	0.0209	0.0263	0.0254	0.0189	0.0162	0.0154	0.0112	0.0111	0.0265	0.0463	0.0112	0.0124	0.0152	0.0266	0.0224	0.0153	0.0174	0.0137	0.011	0.0106	0.0101	0.0103	0.0104	0.0131	0.0168	0.0195	0.0383	0.0135	0.0162	0.0167	0.0124	0.0128	0.013	0.0114	0.011	0.0189	0.0308	0.0307	0.0283	0.0245	0.0214	0.0171	0.018
SO₂ (ppm)	0.00117	0.00177	0.0017	0.00141	0.00106	0.001	0.001	0.001	0.001	0.00219	0.00126	0.001	0.00106	0.00167	0.00187	0.0015	0.00119	0.00177	0.0018	0.001	0.001	0.00103	0.001	0.001	0.001	0.0013	0.00171	0.00136	0.00103	0.001	0.001	0.001	0.001	0.001	0.001	0.001	0.001	0.00107	0.00131	0.00111	0.001	0.001	0.00103	0.001	0.001	0.001	0.001	0.001	0.0011	0.0023	0.00145	0.00104	0.001	0.001	0.001	0.001
CO (ppm)	0.548	0.884	1.14	0.961	0.888	0.827	0.84	1.15	0.616	0.541	0.463	0.498	0.638	1.08	1.22	0.935	0.861	0.94	0.84	0.761	0.644	0.684	0.694	0.597	0.624	0.84	1.02	0.992	0.904	0.86	0.849	0.672	0.571	0.543	0.611	0.692	0.647	0.891	0.985	1.14	1.13	0.941	0.937	0.889	0.99	0.843	0.863	0.931	0.892	1.46	1.29	1.45	1.11	1.01	0.889	1.09

A dot on the chart and a dash in the table indicate missing data. Historical values do not describe today’s air quality.

How should I interpret the data and averaging period? →

OpenAQ ↗

Historical data by station 1

AIR QUALITY ARCHIVE · Si Phum, Mueang

Si Phum, Mueang

Station code: Si Phum, Mueang

Monthly monitoring station data.

PM10Lowest 21.6 2018-09Highest 118 2016-042015-10 - 2020-05

Scroll the chart or table sideways to see the full period.

Si Phum, Mueang · monthly averages · units shown beside each pollutant
Pollutant	2020-05	2020-04	2020-03	2020-02	2020-01	2019-12	2019-11	2019-10	2019-09	2019-08	2019-07	2019-06	2019-05	2019-04	2019-03	2019-02	2019-01	2018-12	2018-11	2018-10	2018-09	2018-08	2018-07	2018-06	2018-05	2018-04	2018-03	2018-02	2018-01	2017-12	2017-11	2017-10	2017-09	2017-08	2017-07	2017-06	2017-05	2017-04	2017-03	2017-02	2017-01	2016-12	2016-11	2016-10	2016-09	2016-08	2016-07	2016-06	2016-05	2016-04	2016-03	2016-02	2016-01	2015-12	2015-11	2015-10
PM10 µg/m³	30.1	79.8	109	88	69.4	59	47.2	37.3	34.2	28.6	30.4	26.7	49.8	82.6	103	59.6	35.7	29.4	29.7	23.5	21.6	30.9	36.2	38.3	33.2	61.4	85.6	64	39.9	41.5	39.1	38.3	36.7	40.2	36	35.3	47	67.1	69.2	58.9	36.3	38.9	32.4	28.5	27.9	29.7	28.1	24.5	49.5	118	107	82.2	57.8	46.6	35.3	48.3
NO₂ (ppm)	—	—	0.0218	0.0261	0.0253	0.0212	0.0158	0.0107	0.00923	0.00903	0.00642	0.0077	0.014	0.0209	0.0263	0.0254	0.0189	0.0162	0.0154	0.0112	0.0111	0.0265	0.0463	0.0112	0.0124	0.0152	0.0266	0.0224	0.0153	0.0174	0.0137	0.011	0.0106	0.0101	0.0103	0.0104	0.0131	0.0168	0.0195	0.0383	0.0135	0.0162	0.0167	0.0124	0.0128	0.013	0.0114	0.011	0.0189	0.0308	0.0307	0.0283	0.0245	0.0214	0.0171	0.018
SO₂ (ppm)	0.00117	0.00177	0.0017	0.00141	0.00106	0.001	0.001	0.001	0.001	0.00219	0.00126	0.001	0.00106	0.00167	0.00187	0.0015	0.00119	0.00177	0.0018	0.001	0.001	0.00103	0.001	0.001	0.001	0.0013	0.00171	0.00136	0.00103	0.001	0.001	0.001	0.001	0.001	0.001	0.001	0.001	0.00107	0.00131	0.00111	0.001	0.001	0.00103	0.001	0.001	0.001	0.001	0.001	0.0011	0.0023	0.00145	0.00104	0.001	0.001	0.001	0.001
CO (ppm)	0.548	0.884	1.14	0.961	0.888	0.827	0.84	1.15	0.616	0.541	0.463	0.498	0.638	1.08	1.22	0.935	0.861	0.94	0.84	0.761	0.644	0.684	0.694	0.597	0.624	0.84	1.02	0.992	0.904	0.86	0.849	0.672	0.571	0.543	0.611	0.692	0.647	0.891	0.985	1.14	1.13	0.941	0.937	0.889	0.99	0.843	0.863	0.931	0.892	1.46	1.29	1.45	1.11	1.01	0.889	1.09

A dot on the chart and a dash in the table indicate missing data. Historical values do not describe today’s air quality.

How should I interpret the data and averaging period? →

OpenAQ ↗Thailand

Environment and quality of life ratings · Chiang Mai

Archived ratings of the local environment: green spaces, cleanliness, noise and water quality. Opinion indicators are separate from pollutant concentration measurements.

Indicator	Chiang Mai	laoPDR	Cambodia	Vietnam	Myanmar	Malaysia
Green and Parks in the City	43%	37%	36%	42%	33%	54%
particulate matter PM2.5 (µg/m³)	25	—	—	—	—	—
Pleasure of spending time in the city	32%	38%	32%	30%	24%	48%
particulate matter PM10 (µg/m³)	46	—	—	—	—	—
Air Pollution	81%	72%	68%	78%	83%	53%
Garbage Disposal	51%	20%	25%	24%	12%	47%
Availability and quality of drinking water	55%	51%	48%	43%	34%	56%
Cleanliness and tidiness	49%	32%	25%	29%	18%	47%
Noise and Light pollution	55%	55%	59%	65%	52%	49%
Water Pollution	60%	73%	73%	73%	74%	62%

NO₂ 3.1O₃ 55

September 26, 202608:00

Thailand · air quality in other cities

Bangkok Samut Prakan Province Udon Thani Chonburi Nakhon Ratchasima Hat Yai Pak Kret Si Racha Lampang Khon Kaen Surat Thani Rangsit Ubon Ratchathani Nakhon Si Thammarat Khlong Luang District Nakhon Pathom Rayong Phitsanulok

WEATHER & SURROUNDINGS

Thailand · weather forecast

Daily maximum and minimum temperatures. Forecast point: 15.87, 100.9925. Forecast for a country reference point; conditions in the city may differ.

Scroll the forecast to see the following days.

Thailand · September 23, 2026: minimum temperature 25.9°C, maximum 33.2°C. Wind: 12 km/h. Humidity: 74%.

Full forecast: temperature, rainfall, wind and humidity

Date	Day °C	Min °C	Max °C	Night °C	Rain mm	Wind m/s	Humidity %	Clouds %
2026-09-23	31.2	25.9	33.2	26.8	6.2	3.3	74	24
2026-09-24	30.1	25.3	31.6	26.1	13.2	4.1	79	98
2026-09-25	26.9	25.3	28.6	25.3	22.6	4.7	92	100
2026-09-26	28.7	24.7	29.3	25.1	9.3	5.3	84	93
2026-09-27	25.5	22.8	26.6	23.5	6.8	4.6	88	100
2026-09-28	27.8	23.1	28.2	24.2	32.8	3.8	84	85
2026-09-29	29	23.4	29	24.8	5.5	3.8	77	100
2026-09-30	29.1	23.5	29.1	25.5	2.3	3.8	79	100
2026-10-01	28.5	24.2	28.5	24.5	9.7	2.4	80	100
2026-10-02	25.8	23.3	25.8	23.8	22.8	1.4	91	100
2026-10-03	24.7	22.8	25.9	24.2	9.8	1.7	94	99
2026-10-04	29.1	23.1	29.1	24	25.9	3.9	78	86
2026-10-05	29.3	23.1	29.3	24.6	10.4	2.7	75	99
2026-10-06	30.2	23.7	30.2	25.1	3.4	2.1	72	88
2026-10-07	29.7	24.2	29.7	24.5	12.1	2.9	75	97
2026-10-08	31.1	24.1	31.1	25.6	1.8	1.7	68	51
2026-10-09	30.8	23.7	30.8	25.9	8.8	1.8	68	88
2026-10-10	31.4	23.8	31.4	25.5	4.7	3.9	68	45

UV index by day · Thailand

Data for a country reference point. Local conditions may differ.

SPF 50, long sleeves and shade between 10:00-16:00.

0-2 low3-5 moderate6-7 high8-10 very high11+ extreme

Scroll the forecast to see the following days.

Thailand · September 25, 2026: UV index: 8.3 .

Indicator	2026-09-25	2026-09-26	2026-09-27	2026-09-28	2026-09-29	2026-09-30	2026-10-01	2026-10-02	2026-10-03	2026-10-04	2026-10-05	2026-10-06	2026-10-07	2026-10-08	2026-10-09	2026-10-10
UV index	8.3	5.8	5.5	7.2	7.3	6.5	4.4	2.3	2.7	7	7.5	6.9	7.5	8	7.7	—

Open-Meteo ↗

AIR QUALITY QUESTIONS

Chiang Mai · air pollution - questions and answers

What do the latest air quality data show for Chiang Mai?

When was PM2.5 highest in Chiang Mai over the past week?

The highest available daily mean PM2.5 was 20.8 µg/m³ (September 22, 2026). This comparison covers 7 days with data in the seven days before September 26, 2026. The day of the latest reading is excluded because it may be incomplete.

What period does the pollution history for Chiang Mai cover?

Available monthly means cover 2015-10 - 2020-05. The tables include PM10, NO₂ (ppm), SO₂ (ppm), CO (ppm). Missing values are marked with a dash, not treated as zero. Monthly archives and current model data may come from different sources.

Is the PM2.5 concentration for Chiang Mai an AQI score?

No. PM2.5 and PM10 are concentrations in µg/m³. AQI is a separate index calculated using a defined scale. When comparing air quality, also check other pollutants, the date and the averaging period.

What UV index does the available forecast show for Chiang Mai?

For September 25, 2026, the forecast UV index is 8.3. The UV section also shows the following available days. The forecast is for a country reference point (Thailand), not the city itself.

What wind speed is forecast for Chiang Mai?

For September 23, 2026, forecast wind speed is 12 km/h. The weather table includes wind, temperature and other available parameters for subsequent days. These data describe a country reference point (Thailand); local wind may differ.

PM2.5 · PM10 · NO₂ · O₃

Understanding air quality and pollution data

What do PM2.5 and PM10 mean?

PM2.5 and PM10 are fractions of airborne particulate matter. PM2.5 covers fine particles up to 2.5 micrometres in diameter, while PM10 covers particles up to 10 micrometres. Concentrations in µg/m³ tell you how many micrograms of particles are present in a cubic metre of air. Compare values over the same time period.

Where does the air pollution data come from?

The latest concentrations come from the CAMS atmospheric model via Open-Meteo for each city’s coordinates. Values describe a model area, so conditions on individual streets may differ. Historical monitoring station data is shown separately where available.

How does PM2.5 concentration differ from AQI?

PM2.5 is the concentration of one particle fraction, expressed in µg/m³. AQI is an index calculated using a particular scale and thresholds. The pollutant cards show concentrations. Our city ranking compares PM2.5; PM10, ozone, nitrogen dioxide and other available gases add to the picture of air quality.

Which dates do the values and charts cover?

Each current value has a data date and time. Current concentration cards show the latest available hour, daily charts summarise individual days, and monthly records let you compare longer periods. These values represent different time intervals.

How can I check pollution in my city?

Search for your city and open its air quality page. Start with PM2.5 and PM10, then check the other available pollutants and the data timestamp. Charts and tables help you compare concentrations over time. Weather and historical climate information complement the pollution data.

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