CHARACTERIZATION OF SOURCES OF LEAD IN THE URBAN AIR OF ASIA USING RATIOS OF STABLE LEAD ISOTOPES

Airborne particulate matter was collected at urban sites in six Asian countries (Japan, Korea, China, Thailand, Sri Lanka, and Indonesia), a nd the stable lead isotope ratios were measured. Some source-related m aterials, such as coal and leaded gasoline, were also analyzed and com pared to the ratios observed in airborne lead. Airborne lead isotope r atios differed considerably from each other, and these differences cor responded to differences in the regional source of lead. Leaded gasoli ne was still the primary source of lead in some cities in Asia, and th e lead isotope ratios were strongly influenced by those of leaded gaso line. In Chinese and Korean cities, however, the considerable effect f rom coal combustion and industrial activity was also observed in their isotope ratios, despite leaded gasoline use. On the other hand, only refuse incineration was a possible single source of lead in Japanese a ir from the view of lead isotope ratios.