CURRENT SOURCE APPORTIONMENT STUDIES IN ASIA: AN OVERVIEW

Abstract:

We reviewed the existing literature on source apportionment of particulate air pollution (PM) in Asian cities as part of a broader review of the literature on the health effects of air pollution in developing Asia. We searched three on-line databases, the Web of Science, PubMed, and Google Scholar, as well as all of the major journals where air pollution and source apportionment peer-reviewed papers are published, and identified 15 Asian cities in which PM measurements were made since 1995 and at some representative background sites. Each study had used receptor-based methods, Chemical Mass Balance (CMB) Analysis, Principal Component Analysis (PCA), and Positive Matrix Factorization (PMF), or other chemical speciation methods currently accepted for source apportionment work, to study the complex mixture of sources that make up the urban atmosphere. Because the studies had employed different source apportionment methodologies, and had used different source categories to describe their results, we grouped their results into five major source categories consisting of mobile, stationary, biomass, fugitive, and other. The highest fine particulate matter concentration was observed in Beijing, Hanoi, Delhi, and Kolkata reaching over 100-g-m3 (annual average). For some major cities the ratios of PM2.5 to PM10 were provided or could be calculated. South Asian cities seem to have a higher coarse fraction in their PM compared to East Asian cities. This ratio ranges between 0.22 and 0.35 in the South Asian cities of Dhaka, Rajshahi, Chennai, Islamabad, and Chak Shahzad where road dust, soil dust, and uncontrolled construction dust dominate in the ambient air. With progressive development in recent years, this ratio is probably shifting to equal portion of both fine and coarse fractions as seen in many East Asian cities. In Bangkok, Beijing, Taiwan, and Bandung, the fine fraction slightly dominates the coarse fraction as vehicle emissions and industrial activity have progressively increased in the last decade. In more developed countries of South Korea and Japan this ratio is higher reaching as high as 0.77 for Seoul. The increased fine fraction compared to the coarse fraction provides an insight of the composition and the complex mixture of sources of the aerosol in these cities. This work was funded by the Health Effects Institute (HEI).