Beijing's Marathon Run to Clean Foul Air Nears Finish Line

摘要

Looking south from the roof of the Institute of Remote Sensing Applications (IRSA) in Beijing, the new Olympic Stadium known as the Bird's Nest shimmers on a hazy horizon. IRSA may not have a ringside seat for the competition that begins here next week, but it is on the frontlines of an Olympian struggle now reaching a climax: the grueling effort to clean Beijing's air. Since 1 June, instruments perched atop IRSA-one of 14 stations in the Beijing region run by a team from six Chinese Academy of Sciences (CAS) institutes-have been monitoring gases and particulate matter around the clock. The stakes are high: In 2001, Beijing Olympics organizers vowed that concentrations of four of the worst pollutants-sulfur dioxide (SO_2), nitrogen dioxide (NO_2), carbon monoxide, and particulate matter less than 10 micrometers in diameter (PM_(10))-would meet World Health Organization (WHO) guidelines by 2008. Since then, the goalposts have shifted. In 2004, Beijing officials said that concentrations of PM_(10) would be reduced to levels comparable with other major cities in developing countries and that tropospheric ozone-a corrosive molecule that sunlight shears off from NO_2, volatile organic compounds, and other precursors-would meet China's air standard, which is more lenient than WHO's.