‍The trend – Over the past few weeks, we have seen a number of important stories about how air pollution affects human health. These add to the ever-growing pool of evidence documenting its harms, which include respiratory and cardiovascular conditions, cancer, adverse birth outcomes, cognitive impairment and neurodegenerative disease. Recent policy recommendations and changes could make a difference, for better, or worse. Read on to find out more.

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Direct link to Alzheimer’s – Fine particulate matter (PM) air pollution has been linked to a higher risk of Alzheimer’s disease by a major study published in PLOS Medicine. Researchers analysed data from 27.8 million US Medicare recipients aged 65+ between 2000 and 2018, finding that PM2.5 exposure was directly associated with increased Alzheimer’s diagnoses. Although conditions such as hypertension, stroke and depression were considered, they explained only a small proportion of the association. The link remained largely unchanged after adjustment. Notably, the association was slightly stronger among individuals with prior stroke, suggesting neurological effects of pollution beyond vascular pathways.

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A price on health – Air pollution from heavy diesel vehicles is costing Australians AUD6.2bn ($8.2bn) annually in health impacts, according to research by the University of Melbourne. Although trucks and buses comprise just 4% of the national fleet, they generate roughly 25% of exhaust-related pollution. The study links exposure to premature deaths, hospital admissions, asthma and lung cancer, describing heavy vehicle exhaust as comparable to cigarette smoke. Alarmingly, children attending daycare facilities near major roads faced pollution levels equivalent to eight cigarettes daily. The authors have urged policymakers to incorporate health costs into heavy vehicle laws and accelerate cleaner transport transitions.

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Recognised risk – Air pollution was formally recognised as a cancer risk in Europe in early February after its inclusion in the fifth edition of the European Code Against Cancer, published by the International Agency for Research on Cancer on behalf of the European Commission. The updated guidance, developed over four years by more than 60 experts, presents 14 recommendations for individuals and parallel advice for policymakers. Evidence cited indicates air pollution raises overall cancer risk by 11% and cancer mortality by 12%, while 99% of the global population breathes harmful air. The Code urges both behavioural changes and stronger public policy to reduce exposure.

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US rolls back – In the same month, the US Environmental Protection Agency (EPA) repealed 2024 amendments to the Mercury and Air Toxics Standards (MATS), removing tighter limits on mercury, PM and toxic metals from coal- and oil-fired power plants. The rollback ends a mandated 70% cut in mercury emissions from lignite-burning plants and a 67% reduction in metals including lead, nickel and arsenic, alongside scrapping continuous particulate monitoring.

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At what cost? The EPA estimates $670m in savings, whereas the previous administration projected up to $1.9bn in health benefits and $1.4bn in climate benefits. Interestingly, the agency also warns that exposure to methylmercury could put 75,000 US newborns at greater risk of learning disabilities every year. The EPA also recently revoked the “endangerment finding”, which determined that greenhouse gas emissions harm health and wellbeing.

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On the wire – Electrification will undoubtedly help the world tackle the health harms associated with air pollution as it works towards limiting global warming. However, the pace needs to pick up and investing in clean energy solutions, including critical infrastructure, is fundamental for those wanting positive change. Another avenue would be to investigate pollution control and monitoring technologies, which are key to mitigating this potent risk that we face in our daily lives.