A Case Study of Chemical Characteristics of Daytime and Nighttime Ambient Particles in Shanghai, China

Ambient daytime and nighttime PM2.5 (particulate matter with aerodynamic diameter less than 2.5 μm) and TSP (the total suspended particulates) samples were collected at two sites (named Pudong and Jinshan) in Shanghai. The concentrations of PM2.5 and TSP were lower at Pudong than at Jinshan. Higher PM2.5 and TSP concentrations were observed during daytime than nighttime for both sites. Carbonaceous aerosol and secondary sulfate were the most abundant components. Larger enrichment factor (EFs) of Zn, Pb, Cl, and S for Jinshan nighttime were observed than for other sampling periods. PM2.5 showed higher relative spatial uniformity (the coefficients of divergence, COD = 0.18) than TSP (COD = 0.23) during the sampling period. The variations of chemical components and the species ratios showed that the contributions of primary particulate emissions in Jinshan (industrial zone) were more significant than in Pudong (residential zone)