Chemical characteristics and source of size-fractionated atmospheric particle in haze episode in Beijing

The abundance, behavior, and source of chemical species in size-fractionated atmospheric particle were studied with a 13-stage low pressure impactor (ELPI) during high polluted winter episode in Beijing. Thirty three elements (Al, Ca, Fe, K, Mg, Na, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Sr, Zr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, Hg, Tl, and Pb) and eight water soluble ions (Cl−, NO3−, SO42−, NH4+, Na+, K+, Ca2+, and Mg2+) were determined by ICP/MS and IC, respectively. The size distribution of TC (OC+EC) was reconstructed. Averagely, 51.5±5.3% and 74.1±3.7% of the total aerosol mass was distributed in the sub-micron (PM1) and fine particle (PM2.5), respectively. A significant shift to larger fractions during heavy pollution episode was observed for aerosol mass, NH4+, SO42−, NO3−, K, Fe, Cu, Zn, Cd, and Pb. The mass size distributions of NH4+, SO42−, NO3−, and K were dominated by accumulation mode. Size distributions of elements were classified into four main types: (I) elements were enriched within the accumulation mode (