How scientists cracked the puzzle of Beijing’s wintertime smog
Sulphate levels in Chinese capital’s air similar to those produced by volcanic eruptions
Levels of a pollutant linked to diarrhoea and global cooling in Beijing’s notorious smog can approach those produced by volcanic eruptions, according to a newly published international study.
Researchers from Germany, the United States and China recorded extremely high concentrations of sulphate on the Tsinghua University campus in January 2013 during a joint study of air pollution in the Chinese capital.
Sulphate is a salt of sulphuric acid that, in nature, is usually formed in the atmosphere after a volcanic eruption.
The sulphate concentration on the roof of one Tsinghua building hit 300 micrograms per cubic metre of air, comparable to the fallout from the eruption of the Eyjafjallajokull volcano in Iceland in 2010, which produced an average, near-surface concentration of 400 micrograms over Scandinavia.
That might explain why some people experience diarrhoea, a typical effect of sulphate poisoning, on smoggy days, alongside other symptoms linked to air pollution.