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.

United Kingdom's Wales Air Pollution Report

Overview

Air Pollution in Wales

Wales faces significant air pollution challenges. 100% of districts exceed the WHO guideline for clean air. This is putting 3.1 million across 22 districts at risk.

The average PM2.5 over 2023 was 8.6µg/m³. That's 1.7 times the WHO guideline for clean air of 5µg/m³.

This is equivalent of everybody, including children, smoking about 143 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 Wales met the WHO guideline of 5 µg/m³, the average person would live 0.34 years longer.

That's 1.1M years of life stolen from 3.1 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 Wales. These areas face the greatest health burden from air pollution.

1.Caerphilly
0.6 years lost
2.Torfaen
0.6 years lost
3.Rhondda, Cynon, Taff
0.6 years lost
4.Merthyr Tydfil
0.5 years lost
5.Cardiff
0.5 years lost
6.Newport
0.5 years lost
7.Monmouthshire
0.4 years lost
8.Vale of Glamorgan
0.4 years lost
9.Bridgend
0.4 years lost
10.Neath Port Talbot
0.4 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

64.7%

2.0M

10-15 µg/m³

35.3%

1.1M

15-25 µg/m³

25-35 µg/m³

> 35 µg/m³

Districts

All 22 Districts in Wales

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

District	Population	PM2.5 µg/m³	Years Lost
Cardiff	365K	10.1	0.5 years
Swansea	248K	8.5	0.3 years
Rhondda, Cynon, Taff	230K	10.8	0.6 years
Carmarthenshire	195K	7.5	0.2 years
Caerphilly	169K	11.5	0.6 years
Newport	161K	10.1	0.5 years
Flintshire	150K	6.4	0.1 years
Vale of Glamorgan	145K	9.4	0.4 years
Powys	139K	7.5	0.2 years
Bridgend	139K	9.2	0.4 years
Wrexham	137K	6.5	0.1 years
Gwynedd	131K	5.8	0.1 years
Neath Port Talbot	129K	8.9	0.4 years
Pembrokeshire	122K	5.9	0.1 years
Torfaen	101K	11.0	0.6 years
Conwy	100K	5.9	0.1 years
Denbighshire	93K	6.0	0.1 years
Monmouthshire	91K	9.6	0.4 years
Ceredigion	77K	6.3	0.1 years
Merthyr Tydfil	73K	10.2	0.5 years
Blaenau Gwent	70K	8.3	0.3 years
Anglesey	52K	5.2	0.0 years

Showing 22 districts, sorted by population (largest first). PM2.5 values are for 2023. Years lost calculated against WHO guideline of 5 µg/m³.

Breathing in Wales is Injurious to Health.