Characteristics of Pb isotope ratios and concentrations in TSP samples from long-range transport in Korea from August 2015 to October 2016

Lead (Pb) is a toxic heavy metal even at low exposure levels and has been recognized as a major public health risk. Lead is released by various natural and anthropogenic sources to the atmosphere and small Pb-containing particles are transported over long distances through the prevailing wind systems, causing atmospheric pollution on local, regional, and intercontinental scales. After the virtual phase-out of leaded gasoline in the world, East Asia, particularly China, becomes the largest contributor for anthropogenic atmospheric Pb emissions with the rapid economic growth and industrialization during the past decades. In order to characterize the impacts of long-range transported Pb on the atmospheric Pb levels in Korea, we have analyzed Pb concentrations and its isotopic compositions in aerosols collected at three sites in Korea. A total of 144 aerosol samples (total suspended particulate, TSP) were collected at Incheon (IC, urban and industrial area), Taean (TA, rural coastal area) and Jeju (JJ, remote area in an island) from August 31, 2015 to October 6, 2016.

The mean concentrations of atmospheric Pb at IC, TA, and JJ sites were 16.2 ± 14.1 ng m^-3, 11.1 ± 8.06 ng m^-3, and 6.29 ± 6.33 ng m^-3 respectively. These Pb levels are comparable to those in Japan, but appear to be much lower than those observed in Chinese cities. Combing Pb isotope compositions and the HYSPLIT air mass back trajectories, we identified the dominant source affecting atmospheric Pb cycling at individual sites between the seasons. The results show that contribution from China amounted to be 41% for IC, 57% for TA, and 39% for JJ, respectively, during the whole period investigated. Chinese contribution is observed to increase in winter and spring and decrease in summer and autumn as a response to the Asian winter and summer monsoons.