During the Olympic period in 2008, concentration of SO2, NO2 and O3 in urban area should reach the WHO guidelines and the particles should be comparable to that in the major cities in the developed countries.

• 其中，2008年奥运会举办期间，市区大气中二氧化硫、二氧化氮、臭氧指标达到世界卫生组织指导值的要求，颗粒物指标达到发达国家大城市水平。