How harmful is air pollution to your health?

Air pollution is one of the most dangerous health risks in the world. Each year, an estimated 2.4 million people die prematurely because of it. Researchers now compare the harm to that of smoking and advocate for equally strict policy. The effects have been robustly demonstrated in Europe, North America, and East Asia^1,2,3.

Fine particulate matter (PM2.5, particles that penetrate deep into the lungs) and ozone increase the risk of serious lung diseases such as COPD and asthma, as well as heart attacks. Measurable damage to the lungs, blood vessels, and DNA is already visible before any symptoms appear⁴. Most of the associations come from observational research, so a direct cause-and-effect relationship is not always fully established. For pregnant women and birth outcomes, however, researchers do consider the association likely causal.

Pregnant women and their unborn children are especially vulnerable. For every increase of 10 micrograms of fine particulate matter per cubic metre, birth weight falls by approximately half a percent. The risk of low birth weight rises by 22% and the risk of preterm birth by 16%. The harm is greatest in the third trimester and among mothers with lower levels of education⁵. After birth the risk persists: early exposure is associated with more respiratory complaints, allergies, and delays in brain development⁶.

There is also good news. Stricter regulations on diesel engines and clean-air policies show that premature deaths can genuinely be reduced^1,7. More greenery in cities also helps: measurably greater vegetation is associated with around 3% lower cardiovascular mortality, likely because greenery counteracts pollution, noise, and heat⁸. The total harm remains difficult to measure precisely, because air pollution consists of many different substances simultaneously.