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8 February 2023

Hidden harms of indoor air pollution — five steps to expose them

Dirty outdoor air might grab the headlines, but learning how pollutants inside buildings form, accumulate and affect our health is equally crucial.

Air pollution is a leading cause of illness — from asthma1 to heart disease, stroke, lung cancer2 and, probably, dementia3. For outdoor air pollution, improved standards and regulations, guided by science, have over the past three decades markedly driven down emissions of particulates, nitrogen oxides and sulfur dioxide in many parts of the world4. Indoor air pollution hasn’t received the same attention, even though it might cause almost as many deaths globally — 3.2 million in 2020, according to the World Health Organization (WHO), compared with around 3.5 million linked to polluted outdoor air (see

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