PCDD/F measurement at a high-altitude station in Central Taiwan: evaluation of long-range transport of PCDD/Fs during the Southeast Asia biomass burning event.

Recent biomass burning in Southeast Asia has raised global concerns over its adverse effects on visibility, human health, and global climate. The concentrations of total suspended particles (TSPs) and other vapor-phase pollutants (CO and ozone) were monitored at Lulin, an atmospheric background station in central Taiwan in 2008. To evaluate the long-range transport of persistent organic pollutants (POPs) during the Southeast Asia biomass burning event, the atmospheric polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were also measured at Lulin station. The atmospheric PCDD/F and TSP concentrations measured at Lulin station ranged from 0.71-3.41 fg I-TEQ/m(3) and 5.32-55.6 microg/m(3), respectively, during the regular sampling periods. However, significantly higher concentrations of PCDD/Fs, TSPs, CO, and ozone were measured during the spring season. These high concentrations could be the result of long-range transport of the products of Southeast Asia biomass burning. During the Southeast Asia biomass burning event (March 18-24, 2008), an intensive observation program was also carried out at the same station. The results of this observation program indicated that the atmospheric PCDD/F concentration increased dramatically from 2.33 to 390 fg I-TEQ/m(3) (March 19, 2008). The trace gas (CO) of biomass burning also significantly increased to 232 ppb during the same period, while the particle-bound PCDD/Fs in the TSP increased from 28.7 to 109 pg I-TEQ/g-TSP at Lulin station during the burning event. We conclude that there was a significant increase in the PCDD/F concentration in ambient air at a high-altitude background station in central Taiwan during the Southeast Asia biomass burning event.