Source apportionment research of fine particulate matter in the atmosphere by PAHs

Abstract

Haze weather frequently occurs in many cities in China. Polycyclic aromatic hydrocarbons(PAHs) in fine particulate matter(PM2.5) can adversely affect the environment and human health. In this paper, PM2.5 samples were collected at nine sites in a city in northeastern China from September 2013 to October 2014. Sixteen USEPA(US Evironment Protection Agency) priority PAHs in PM2.5 were analyzed to determine their spatial and temporal distribution characteristics. The source apportionment of PAHs was conducted with the Positive Matrix Factorization(PMF) model. The results indicate that the concentrations of total PAHs(T-PAHs) in PM2.5 are within the range of 0.26 to 72.48 ng/m3. The seasonal variation of T-PAHs is winter>spring>autumn>summer, and the space distribution of PAHs is JZP>DP>BFH>LP> EESA>IPT>CP>HZMC>JYP. In all types of PAHs, three-ring and five-ring PAHs are significantly prominent(62%) in the heating period due to petrogenic sources and traffic emissions. Middle- and high-ring PAHs in the non-heating period are caused by coal combustion and vehicle exhaust, which accounts for 77% of the total emissions. The source apportionment results obtained by the diagnostic ratio of PAHs reflect that coal burning, traffic and other sources have a distinct influence on PAH emissions in this city. Six factors are defined by PMF v5.0, namely, coke oven emissions(7.7%), biomass burning(44.3%), petrogenic sources(10.7%), coal combustion(10.4%), gasoline engine emissions(16.7%), and diesel engine emissions(10.3%). The results indicate that the PAHs in PM2.5 in the city are primarily caused by combustion processes and vehicle exhaust.