PM2.5 in an industrial district of Zhengzhou,China:Chemical composition and source apportionment

Zhengzhou is a developing city in China,that is heavily polluted by high levels of particulate matter.In this study.fine particulate matter(PM) was collected and analyzed for their chemical composition(soluble ions,elements,elemental carbon(EC) and organic carbon(OC)) in an industrial district of Zhengzhou in 2010.The average concentrations of PMwere 181,122,186 and 211μg/m~3 for spring,summer, autumn and winter,respectively,with an annual average of 175μg/m~3,far exceeding the PMregulation of USA National Air Quality Standards(15μg/m~3).The dominant components of PMin Zhengzhou were secondary ions(sulphate and nitrate) and carbon fractions.Soluble ions,total carbon and elements contributed 41%,13%and 3%of PMmass,respectively.Soil dust,secondary aerosol and coal combustion, each contributing about 26%,24%and 23%of total PMmass,were the major sources of PM,according to the result of positive matrix factorization analysis.A mixed source of biomass burning,oil combustion and incineration contributed 13%of PM.Fine particulate matter arising from vehicles and industry contributed about 10%and 4%of PM,respectively.