PM2.5 stands for particulate matter 2.5 microns or smaller. These particles are 30 times thinner than a human hair and come from car exhaust, power plants, wildfires, and burning fuel. They are small enough to bypass your body's natural defenses and enter your bloodstream.

How does air pollution affect the body?

Air pollution affects virtually every organ in the body. PM2.5 particles enter your lungs, pass into your bloodstream, and travel to your heart, brain, kidneys, liver, and other organs. This causes chronic inflammation, increasing risks of heart disease, stroke, lung cancer, dementia, and many other conditions.

How many people are affected by air pollution?

99% of the global population breathes air that exceeds WHO safety guidelines. Air pollution kills approximately 8 million people every year—more than AIDS, malaria, and tuberculosis combined.

Thailand's Chiang Mai Air Pollution Report

Overview

Air Pollution in Chiang Mai

Chiang Mai faces significant air pollution challenges. 100% of districts exceed the WHO guideline for clean air. This is putting 1.7 million across 24 districts at risk.

The average PM2.5 over 2023 was 33.3µg/m³. That's 6.7 times the WHO guideline for clean air of 5µg/m³.

This is equivalent of everybody, including children, smoking about 552 cigarettes in a year.

Trends

Air Quality Trend

Annual PM2.5 levels from 2014 to 2023. The WHO guideline for safe air is 5 µg/m³.

Health Impact

Life Expectancy Impact

If Chiang Mai met the WHO guideline of 5 µg/m³, the average person would live 2.78 years longer.

That's 4.8M years of life stolen from 1.7 million people. Years of watching children grow up. Years of building a career. Years of quiet mornings and celebrations.

Lives cut short. Breathing kills.

Most Polluted

Districts with Highest Pollution

The top 10 most polluted districts in Chiang Mai. These areas face the greatest health burden from air pollution.

1.Fang
3.2 years lost
2.Mae Ai
3.2 years lost
3.Chai Prakarn
3.1 years lost
4.Phrao
3 years lost
5.San Kamphaeng
3 years lost
6.Doi Saket
3 years lost
7.San Sai
2.9 years lost
8.Saraphi
2.9 years lost
9.Muang Chiang Mai
2.9 years lost
10.Chiang Dao
2.9 years lost

Exposure

Population Exposure by Pollution Level

Distribution of population across different PM2.5 pollution levels. The WHO guideline is 5 µg/m³—only populations below this threshold are breathing safe air.

< 5 µg/m³

5-10 µg/m³

10-15 µg/m³

15-25 µg/m³

25-35 µg/m³

73%

1.3M

> 35 µg/m³

27%

464K

Districts

All 24 Districts in Chiang Mai

Complete air quality data for every district in Chiang Mai, sorted by population.

District	Population	PM2.5 µg/m³	Years Lost
Muang Chiang Mai	252K	34.5	2.9 years
Fang	110K	38.0	3.2 years
San Sai	107K	35.0	2.9 years
Mae Rim	89K	33.3	2.8 years
San Kamphaeng	88K	35.3	3.0 years
Saraphi	87K	34.5	2.9 years
San Pa Tong	85K	31.5	2.6 years
Doi Saket	83K	35.2	3.0 years
Hang Dong	83K	32.7	2.7 years
Mae Taeng	82K	32.7	2.7 years
Chiang Dao	77K	34.2	2.9 years
Mae Ai	76K	38.0	3.2 years
Mae Chaem	69K	27.0	2.2 years
Chom Thong	67K	29.2	2.4 years
Phrao	58K	35.4	3.0 years
Omkoi	52K	25.4	2.0 years
Chai Prakarn	48K	36.6	3.1 years
Hot	48K	27.2	2.2 years
Mae Wang	34K	29.9	2.4 years
Doi Tao	30K	28.6	2.3 years
K. Doi Lo	28K	30.7	2.5 years
Samoeng	25K	29.2	2.4 years
Wiang Haeng	23K	32.1	2.7 years
K. Mae On	17K	32.3	2.7 years

Showing 24 districts, sorted by population (largest first). PM2.5 values are for 2023. Years lost calculated against WHO guideline of 5 µg/m³.

Breathing in Chiang Mai is Injurious to Health.