Influence of sandstorms on levels of Polycyclic Aromatic Hydrocarbons (PAHs) in PM_(2.5) in southern China

摘要

Polycyclic Aromatic Hydrocarbons (PAHs) in PM_(2.5) samples were collected at Mount Heng in southern China during spring-summer of 2009 and quantitated by GC/MS. Under the influence of sandstorms, the mean volume concentration of PM_(2.5) was 150.61 μg/m~3, which was much higher than that measured in the absence of sandstorms (58.50 μg/m~3). On sandstorm days, total PM_(2.5) PAHs average mass concentration was 30.70 μg/g, which was much lower than that detected with no sandstorm (80.80 μg/g). As a result, sandstorms increased particulate levels and reduced visibility. On the other hand, sandstorms decreased the concentration of PAHs due to dilution and turbulence effect. The distribution characteristics of individual PAH species in PM_(2.5) under sandstorm conditions indicated that the pollutants at Mount Heng were mainly from incomplete combustion and pyrolysis of fuels and were transported to the sampling site. These results were different from usual days. Under the influence of sandstorms, concentrations of 4-ring and 5-ring PAHs were low, even not detected, whereas 6-ring PAHs were the most abundant.