Gas/particle partitioning, particle-size distribution of atmospheric polybrominated diphenyl ethers in southeast...

A size-segregated gas/particle partitioning coefficient K_Pi was proposed and evaluated in the predicting models on the basis of atmospheric polybrominated diphenyl ether (PBDE) field data comparing with the bulk coefficient K_P. Results revealed that the characteristics of atmospheric PBDEs in southeast Shanghai rural area were generally consistent with previous investigations, suggesting that this investigation was representative to the present pollution status of atmospheric PBDEs. K_Pi was generally greater than bulk K_P, indicating an overestimate of TSP (the mass concentration of total suspended particles) in the expression of bulk K_P. In predicting models, K_Pi led to a significant shift in regression lines as compared to K_P, thus it should be more cautious to investigate sorption mechanisms using the regression lines. The differences between the performances of K_Pi and K_P were helpful to explain some phenomenon in predicting investigations, such as P_L⁰ and K_OA models overestimate the particle fractions of PBDEs and the models work better at high temperature than at low temperature. Our findings are important because they enabled an insight into the influence of particle size on predicting models.