The characteristics of environmental particulate matter in the urban area of Beijing, China, during the 2008 Olympic Games

Özet

Atmospheric particulate matter (PM) and street dust samples from the Chaoyang District of easternBeijing were studied over a period encompassing the 2008 Beijing Olympic Games. PM10 concentrationdata are combined with trajectory clustering and potential source contribution function (PSCF) methodsto identify the principal transport pathways. Sources for high-concentration aerosol events and airflowfrom the surrounding Hebei Province and Shandong Province to the southeast are found to exert themost significant external influence on Beijing's air quality. China undertook a number of initiatives toimprove air quality for the Olympic Games and we show that PM10 concentrations and magnetic susceptibility were significantly lower during the Olympic period compared to the pre-Olympic periodconfirming that controlling local sources in Beijing and shutting factories in surrounding provincessubstantially improved air quality. On short timescales PM10 shows an inverse correlation to relativehumidity and hence precipitation which acts to improve air quality. Atmospheric PM and street dustremained high through the Olympic period probably due in part to redistribution of historical sourcesand implying that the aim of zero pollution is not achievable in the short term. Analysis of the heavymetal content in both PM and street dust identifies consistently high values of Zn, with Pb relativelyhigher in the PM; a primary source in vehicular emissions therefore seems likely.