Characterization of carbonaceous aerosols during and post-Shenzhen UNIVERSIADE period

The 26th UNIVERSIADE, and event that (briefly describe, including PM2.5 controls that were put in place) was successfully held in Shenzhen during Aug.12th ~ 24th, 2011. Monitored PM2.5 (aerodynamic diameter??2.5 ??m) mass concentrations measured (12.99??3.73) ??g/m3 and (25.24??5.20) ??g/m3 at two selected sampling sites. However, significant increase in PM2.5 mass appeared after the UNIVERSIADE, when the control measures were terminated. At this time, PM2.5 mass concentrations were (48.01??8.73) ??g/m3 and (54.05??6.53) ??g/m3, respectively. In this study, elemental carbon was used as a tracer to estimate the contamination levels of primary and secondary carbonaceous aerosols both during and after the UNIVERSIADE event. Results show that primary organic carbon post-UNIVERSIADE increased by 55% and 22% and the secondary organic carbon increase by 442% and 169% at the two sites, respectively. Considering meteorological factors and backward trajectory clustering modeling, both long-distance particle transportation and local contamination accumulation contribute to the air quality degradation, among which secondary atmospheric reactions might be the major factor leading to the observed PM2.5 increase.EI081972-19783