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.

Kenya's Nairobi Air Pollution Report

Overview

Air Pollution in Nairobi

Nairobi faces significant air pollution challenges. 100% of districts exceed the WHO guideline for clean air. This is putting 5.4 million across 17 districts at risk.

The average PM2.5 over 2023 was 17.8µg/m³. That's 3.6 times the WHO guideline for clean air of 5µg/m³.

This is equivalent of everybody, including children, smoking about 295 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 Nairobi met the WHO guideline of 5 µg/m³, the average person would live 1.26 years longer.

That's 6.8M years of life stolen from 5.4 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 Nairobi. These areas face the greatest health burden from air pollution.

1.Embakasi North
1.3 years lost
2.Kamukunji
1.3 years lost
3.Mathare
1.3 years lost
4.Ruaraka
1.3 years lost
5.Makadara
1.3 years lost
6.Embakasi Central
1.3 years lost
7.Embakasi West
1.3 years lost
8.Starehe
1.3 years lost
9.Embakasi East
1.3 years lost
10.Embakasi South
1.3 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

100%

5.4M

25-35 µg/m³

> 35 µg/m³

Districts

All 17 Districts in Nairobi

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

District	Population	PM2.5 µg/m³	Years Lost
Kasarani	620K	17.9	1.3 years
Starehe	567K	18.1	1.3 years
Embakasi East	533K	18.1	1.3 years
Langata	443K	17.3	1.2 years
Dagoretti South	388K	16.5	1.1 years
Roysambu	384K	17.5	1.2 years
Westlands	320K	17.4	1.2 years
Embakasi South	269K	18.0	1.3 years
Embakasi West	265K	18.3	1.3 years
Kibra	256K	17.6	1.2 years
Kamukunji	243K	18.4	1.3 years
Embakasi Central	240K	18.3	1.3 years
Dagoretti North	229K	17.4	1.2 years
Makadara	229K	18.4	1.3 years
Embakasi North	140K	18.4	1.3 years
Ruaraka	137K	18.4	1.3 years
Mathare	107K	18.4	1.3 years

Showing 17 districts, sorted by population (largest first). PM2.5 values are for 2023. Years lost calculated against WHO guideline of 5 µg/m³.

Breathing in Nairobi is Injurious to Health.