Persistent organic pollutants in tropical coastal and offshore environment: part A—atmospheric polycyclic aromatic hydrocarbons

Air samples were collected at four sites from August 2009 to May 2010. Temporal variation of polycyclic aromatic hydrocarbon (PAH) concentrations showed the highest concentration in November and the lowest in May, except for one case attributable to a specific meteorological event, a typhoon, which resulted in a dramatic increase in PAHs concentrations. PAH compositional pattern, diagnostic ratios, hierarchical cluster analysis, and principal component analysis indicated that the major sources of PAHs in the Gaoping coastal area were local vehicle emissions, stationary sources, and coal/wood combustion. In addition, the distinct compositional patterns at each sampling site suggested that sources of PAHs varied with sampling periods. Back trajectory analysis indicated that transport pathway and moving speed of air parcels were two important factors that influence temporal and spatial variation of PAH concentrations. Air parcel pathways and PAH compositional patterns also indicated that PAHs observed at an offshore island (Liu-Chiu Isle) in November were affected by sources in the southwest coastal area of Taiwan. The data set of PAH concentrations built in this study provides useful information to estimate air–water exchange behavior of PAHs and to investigate the fate of PAHs in the Gaoping coastal area.

Keywords
Seasonal variation; Source identification; Back trajectory analysis; Air parcel pathway