[Distribution Characteristics and Source Analysis of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Dust of Xi'an City, China].

A total of 58 surface dust samples were collected from Xi'an city. The concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) were analyzed by gas chromatography with a flame ionization detector (GC-FID). At the same time, the distribution and sources of PAHs in surface dust were studied. The results showed that the concentrations of individual PAH ranged from 14.69 to 6370. 48 microg x kg(-1), and the total concentrations of 16 PAHs (∑16 PAHs) ranged from 5039.67 to 47,738.50 microg x kg(-1), with a mean of 13,845.82 microg x kg(-1). Compared to the Y PAHs levels of other cities, the ∑16 PAHs in surface dust of Xi'an belonged to a relatively higher level. PAHs in surface dust were mainly dominated by high molecular weight PAHs with 4-6 rings and the concentration of 7 carcinogenic PAHs (1 CPAHs) accounted for 46.08% of 3 16PAHs. The mean of ∑16 PAHs in surface dust had the highest concentration at industrial area; followed by the educational area, traffic area, business and traffic area; residential area and parks showed relatively lower concentration. The average content of ∑16 PAHs in surface dust presented an increasing trend along the main urban area--the second ring road--the third ring road. ∑16 PAHs in surface dust had higher concentrations at the industrial areas of the east and west suburbs of Xi'an, the south suburb and the north section of the second ring road; ∑16 PAHs concentrations in the main urban area, north suburb and southeast part of Xi'an were relatively lower. The results of ratio, cluster analysis and principal component analysis showed that PAHs in surface dust were mainly originated from the combustion of fossil fuels and coal combustion. Among them, diesel combustion reached 36.07%, gasoline combustion accounted for 32.31%, and coal combustion was resposbe for 23.40%