论文部分内容阅读
To understand pollution characteristics of chemical composition, the particles samples were collected by two Andersen cascade impactors in Nanjing northern suburb during May to July in 2013.Major components of PM2.1 reported as ionic compositions, carbon species and metallic elements.The PM2.1 samples were analyzed for its chemical compositions (Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Zn, Mo, Cd, Ba, Pb, Na+, NH4+, K+, Mg2+, Ca2+, Cl-,NO3-, SO42-, OC and EC).The SO42-, NH4+ and NO3-were the mainly ionic species, accounting for 78.54% in total ions mass in PM2.1.The concentration of OC ranged between 5.14 and 26.98μg·m-3, with an average of 13.04μg·m-3, while EC between 0.80 and 7.46, with an average of 2.61μg·m-3.Ca, Na, Fe and K dominated the collected elements in PM2.1 in summer, accounting for 70.17% of total elemental mass, Cr, A1, Mg, Zn and V accounted for 27.53% of total elemental mass, the other elements insufficiently accounted for 3% of total elemental mass.The positive matrix factorization version 3 (EPA-PMF 3.0) was applied to identify the source contribution of PM2.1 concentrations at the study area.Source categories were determined based on chemical component abundances in source profiles.Overall, results indicated that seven factors were obtained, indentified as (Ⅰ) secondary aerosol characterized by high concentrations of NH4+, NO3" and SO42-, accounting for 20.22%;(Ⅱ) metallurgical aerosol characterized by high concentrations of Pb, Cd and Zn, accounting for 6.71%;(Ⅲ) road dust characterized by high concentrations of Mg, Ca, Na, Al and Ba, accounting for 11.85%;(Ⅳ) biomass burning characterized by high concentrations of K+, Na+, Cl-and K, accounting for 10.17%;(Ⅴ) residual oil characterized by high concentrations of V and Cr, accounting for 16.63%;(Ⅵ) iron and steel industry characterized by high concentrations of Mn and Fe, accounting for 9.48%;(Ⅶ) Vehicle Exhaust characterized by high concentrations of OC, Mo, EC and K, accounting for 24.94%.