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), and the stable lead isotope ratios were measured. Some source-related materials, such as coal and leaded gasoline, were also analyzed and compared to the ratios observed in airborne lead. Airborne lead isotope ratios differed considerably from each other, and these differences corresponded to differences in the regional source of lead. Leaded gasoline was still the primary source of lead in some cities in Asia, and the lead isotope ratios were strongly influenced by those of leaded gasoline. In Chinese and Korean cities, however, the considerable effect from 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 air from the view of lead isotope ratios.