Variation of PM10 Flux and Scenario Analysis before and after the Olympic Opening Ceremony in Beijing

An investigation of PM10(the synoptic patten and particle matter less than 10 μm) transport variation before and after Beijing Olympics (20 Jul to 24 Aug 2008) was performed through fluxes simulation carried on the Nested Air Quality Prediction Modeling System (NAQPMS). Results showed large magnitude and distribution variations of PM10 fluxes, essentially southerly, southeasterly, and easterly, due to changes in meteorological conditions. Before the Olympics opening ceremony, the most important fluxes transported into Beijing were southerly (55.8%) and southeasterly (29.4%) versus significant changes in a range of 38.1% and 47% respectively during the Olympic games (8－24 Aug 2008) with significant decrease of total flux from 50 t·h-1 to 40.2 t·h-1. Vertically, the strongest PM10 transport occurred in the lower boundary layer before 8 Aug, while an almost homogeneous transport prevailed during the Olympics games. An in-deep analysis was performed on the impact of meteorology and emissions on PM10 transport and air quality over Beijing through substitution between 2006 and 2008 emissions data in NAQPMS model, proved that, in sight of the important role meteorological conditions played in regional PM10 transport, emissions control (environmental restrictions) during the Olympic Games was more effective in improving air quality over Beijing.