Millions of deaths could be avoided if the world adopts tough new air pollution limits set out today by the World Health Organization (WHO).
The guidelines call for much lower daily and annual levels of exposure to six pollutants from cars, power stations and other sources, in the first major overhaul听of the recommendations in 16听years. The stricter ceilings are听due to an increase in research on the health impacts from even low levels of pollution.
鈥淲e have even stronger evidence than before on the effect听of air pollution on health. Before our evidence was huge, now it鈥檚 even stronger,鈥� says Maria听Neira at the WHO.
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Stephen Holgate at the University of Southampton, UK, says population-based studies have shown 鈥渢here are no safe levels of air pollution鈥�.
The WHO鈥檚 air quality guidance isn鈥檛 legally binding but influences governments, and clean air campaigners have increasingly been calling for stricter measures.
Under the new advice, annual limits on people鈥檚 exposure to tiny听particulate matter known as PM2.5, which mostly comes from burning fossil fuels in cars and industry, are halved. Annual exposure to nitrogen dioxide, a听toxic gas from diesel vehicles, is听cut by 75 per cent.
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Air pollution is currently the world鈥檚 greatest environmental threat to health, resulting in 7听million premature deaths a year, according to the WHO, although some estimates are even higher.
The WHO calculates that if the world met the new PM2.5 limits, ignoring other measures, it would cut deaths due to PM2.5 by about 80 per cent, or 3.3 million people a听year. 鈥淗ow can you refuse to reduce by 80 per cent?鈥� says Neira.
Air quality experts say the new limits are in line with the science on the health impact of exposure to dirty air. 鈥淭hese are really quite significant developments. It鈥檚 very听dramatic. But it does reflect the current state of the literature,鈥� says Jonathan Grigg at Queen Mary University of London.
鈥淗arms to health occur throughout the entire life course, but pregnancy and childhood are especially vulnerable periods, with mounting evidence for effects on long-term growth and cognitive ability,鈥� says Frank Kelly at Imperial College London. 鈥淲e need to view air pollution much more seriously, as it is a major public health problem.鈥� Meeting the new guidelines is feasible but听will be a challenge, especially in many UK cities, he adds.
Grigg says the UK government should consider immediately adopting the new guidelines, using the Environment Bill moving through parliament. 鈥淲e could lead the world,鈥� he says. A spokesperson for the UK Department for Environment, Food & Rural Affairs says: 鈥淲e will听consider the updated WHO guidelines on PM2.5 to inform the development of air quality targets, but we must not underestimate the challenges these would bring, particularly in large cities and for听people鈥檚 daily lives.鈥�
Globally, 91 per cent of the world鈥檚 population lives in areas that exceed the old limits. Asia has听a particularly high death toll linked to dirty air, with people in听cities across China and India breathing some of the highest levels of particulate pollution.
Because of the difficulty of making such big air pollution cuts,听the WHO has also published easier interim targets. Neira says countries should remember that cleaning up their air will not only听save lives, but protect against future respiratory diseases and help meet climate goals.
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