Taiyuan Rain Analysis Of PAHs And Sources Of Contamination

Distribution, sources and deposition fluxes of16total polycyclic aromatichydrocarbons (PAHs) in rainwater collected from July to November2013inTaiyuan were investigated in this study. The mean concentration of Σ16-PAHswas25542.51ng/L (ranged from5261.63to205818.25ng/L),2~3ring PAHswere the major components, accounting for54.69%,4ring and5~6ring PAHsaccounted for31.77%and13.55%, respectively. The mean concentration ofdissolved of Σ16-PAHs was15751.71ng/L (ranged from3372.95to130299.20ng/L),2~3ring PAHs were the major components, accounting for47.45%,4ring and5~6ring PAHs accounted for39.27%and13.28%, respectively. Themean concentration of particulate of Σ16-PAHs was9790.80ng/L (ranged from3252.39to46909.68ng/L),2~3ring PAHs were the major components,accounting for66.32%,4ring and5~6ring PAHs accounted for19.70%and13.98%, respectively.The tendency of concentration of dissolved Σ16-PAHs isthe same as that of2~3ring PAHs，but it is different from the tendency of4ringPAHs and5~6ring PAHs.The tendency of concentration of particulateΣ16-PAHs is the same as that of4ring and5~6ring PAHs, but it is differentfrom2~3ring PAHs.PAHs in the atmosphere in Taiyuan might be removedeffectively by rainwater, mean deposition fluxes of Σ16-PAHs（dissolved PAHsplus particulate PAHs） was12910.16ng/（m2·d）. There were significantpositive correlations between deposition fluxes of Σ16-PAHs in different monthsand their mean rainfall (p<0.01) and frequencies of rains (p<0.01). The results ofdiagnostic ratios of dissolved and particulate PAHs indicated the source of PAHsin Taiyuan mainly derived from coal combustion, and also some from petroleumcombustion and petroleum. Principal Component Analysis of dissolved andparticulate PAHs indicated that the source of PAHs were mainly from coalcombustion、fossil fuel combustion and oil source.The analysis of backward trajectory analysis showed that the air pollution of Taiyuan was mainlyoriginated local emission.