The hazes can be choking and can reduce visibility at noon to a few tens of yards. Fumes belch from factory chimneys, coal-fired power plants, heating systems in apartment blocks, and millions of road vehicles. When the weather traps smog in the streets, city hospital admissions soar and the morgues fill.
The foul air of dozens of fast-expanding cities across China contains cocktails of toxic contaminants unprecedented in the range of pollutants they contain at high concentrations. Now, new research into these swirling maelstroms of gases and tiny particulates suggests that they may be incubating chemical reactions that compound the health effects in ways not seen before – effects that doctors say are cutting five years off the expected lifespan of half a billion people in northern China.
A study by Chinese and U.S. researchers, published in the bulletin of the World Health Organization (WHO) in February, says the science and regulation of smogs have not kept up with their changing composition in the 21st century. In particular, they do not track the “multi-contaminant” nature of the new smogs. Lijian Han and colleagues from the Chinese Academy of Sciences’ Research Center for Eco-Environmental Sciences in Beijing, who were among the study’s coauthors, are calling for a new approach to assessing the health risks from chemically complex urban smogs – not just in China, but across the fast-industrializing and urbanizing countries of the developing world.
Most monitoring of urban air still concentrates on one or at most two pollutants, sometimes particulates, sometimes nitrogen oxides or sulphur dioxides or ozone. Similarly, most medical studies of the impacts of these toxins look for links between single pollutants and suspected health effects such as respiratory disease and cardiovascular conditions. And most air quality standards – drawn up by the WHO, the U.S. Environmental Protection Agency, Chinese authorities, and others – are still based on limits to the same individual pollutants.
Read more at Yale Environment 360
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