Particle size distributions and gas–particle partitioning of polychlorinated dibenzo-p-dioxins and dibenzofurans in ambient air during haze days and normal days - Liang Yong

Little information is available on the distributions of airborne polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) during haze days. In this study, PCDD/F concentrations, particle size distributions, and gas–particle partitioning in a Beijing suburban area during haze days and normal days were investigated. High PCDD/F concentrations, 3979–74,702 fg m− 3 (173–3885 fg I-TEQ m− 3), were found during haze days and ~ 98% of the PCDD/Fs were associated with particles. Most PCDD/F congeners (> 90%) were associated with particles. PCDD/F concentrations increased as particle sizes decreased and 95% of the particle-bound PCDD/Fs were associated with inhalable fine particles with aerodynamic diameters < 2.5 μm. PCDD/Fs were mainly absorbed in the particles and the Harner–Bidleman model predicted the particulate fractions of the PCDD/F congeners in the air samples well. The investigated …