Predictions of gas-particle partitioning coefficients (K(P)) of polycyclic aromatic hydrocarbons at various occupational environments of Songkhla Province, Thailand.

Ambient air samples were collected over periods of 24 hours and 3 hours using a Graseby-Anderson high volume air sampler with PM10 TE-6001 at 15 sampling sites, including an urban residential zone, rural area, industrial factories, waste incinerator, traffic areas and agricultural burning areas in Songkhla Province, Thailand. An analysis of organic carbon and elemental carbon was conducted to estimate the gas-particle partitioning of PAHs using a model proposed by Dachs-Eisenreich. The estimated LogK(P) of PAHs emphasized the risk for lung cancer among outdoor workers in waste incinerators, traffic intersections and bus terminals, suggesting the role of the carbonaceous fraction over the gas-particle partitioning of PAHs. Analysis of f(SC)K(SA)delta(OCT)/F(OM)K(OA) ratios revealed a significant role of adsorption and absorption in unusually high elemental carbon fractions (ie low OC/EC ratio) in fine particles collected at waste incinerators and the abnormally high organic carbon fractions (ie high OC/EC ratio) observed in those fine particles of an urban residential zone, respectively. The dual mode of ab/adsorption tended to dominate the gas-particle partitioning of LMW PAHs collected at the traffic intersections and bus terminal.