Mass closure analysis and source apportionment of PM2.5 during the wintertime of Xi’an, China

摘要

Chemical characteristics of PM2.5 samples from Xi’ an urban area in January and February 2006, and the sam e periods of 2008 and 2010 were determined in this study . Qualitative ratios including OC2/EC1, NO3~-/SO4~(2-), and Zn/Pb were carried out in PM2.5 samples to illustrat e the changes in PM2.5 emission sources in Xi’an winter (Cao et al., 2005). PM2.5 samples collected during the wintertime o f 2006, 2008 and 2010 were determined for carbon (OC, EC and carbon fractions), water-soluble ions (F~--, Cl-, SO4~(2-) , NO3~-, Na~+, NH4~+, K+, Mg~(2+) and Ca~(2+)) and elements (S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Z n, As, Br, Cd, and Pb) analyses. This information w as especially important for evaluating the changes in PM2.5 mass, chemical compositions and source appo rtionments.