Assessment of variations in atmospheric PCDD/Fs by Asian dust in Southeastern Korea

Atmospheric concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were measured in southeastern Korea during the spring of 2002. During this period, severe Asian dust events (ADs) occurred throughout Korea. Total suspended particulates (TSP) of ADs (456.8 μg m−3) increased approximately 3.6-fold compared with non-Asian dust events (NADs; 128.5 μg m−3). However, the concentrations of PCDD/Fs (average concentration, 3.34 pg m−3) did not increase as much as TSP; there was not a significant difference in the concentrations of particle-bound PCDD/Fs collected between ADs (2.45 pg m−3) and NADs (2.05 pg m−3). Meanwhile, according to TSP levels, the concentrations during NADs were 2.8-fold higher than ADs (16.73 and 5.98 ng g−1-TSP, respectively). High TSP levels during sand storms without an increase in PCDD/Fs reflected an increase in coarse and accumulation mode particles. Gas/particle partitioning studies revealed the additional inputs of particulate matters to the air during ADs which did not relate with the increase of PCDD/Fs. Furthermore, emissions from ADs may consist of relatively complex atmospheric particles; back trajectories showed air masses moving at low altitudes over Korea, but there were no differences in PCDD/Fs or atmospheric pollutants regardless of air movements. The study area, which is located in southeastern Korea, might be affected by both marine and regional anthropogenic sources, which do not appear to cause clear differences in PCDD/F concentrations or congener profiles between different air trajectories.