Quantitative Source Apportionment of Size-segregated Particulate Matter at Urbanized Local Site in Korea

The suspended particulate matter (PM) has been collected by a cascade impactor for 2 years (September 2005-September 2007) in Kyung Hee University-Global Campus located on the border of Yongin and Suwon Cites in Korea. PM was separated into 9 fractions with following aerodynamic size ranges: ST1 (> 9 mu m), ST2 (5.8-9.0 mu m), ST3 (4.7-5.8 mu m), ST4 (3.3-4.7 mu m), ST5 (2.1-3.3 mu m), ST6 (1.1-2.1 mu m), ST7 (0.7-1.1 mu m), ST8 (0.4-0.7 mu m), ST9 (< 0.4 mu m). The 20 chemical species (Al, Mn, Si, Fe, Cu, Pb, Cr, Ni, V, Cd, Ba, Zn, Na+, NH4+, K+, Mg2+, Ca2+, Cl-, NO3-, SO42-) were analyzed by ion coupled plasma atomic emission spectrometry and ion chromatography after proper pretreatments of each sample filter. Based on the chemical information, positive matrix factorization (PMF) was used to identify size-segregated PM sources except for ST9. A total of 11 sources were identified and their contributions were intensively estimated. Further conditional probability function (CPF) was used to examine the potential location of identified sources after PMF modeling, A result of 2-year average source contribution showed that aged sea salt, road dust, long-range transport, and soil sources were most dominant in ST1 (PM > 9.0 mu m); mixed automobiles and coal combustion sources in ST5 (2.1 mu m < PM < 3.3 mu m); oil combustion, secondary aerosol, and incineration in ST8 (0.4 mu m < PM < 0.7 mu m); and biomass burning source in ST7 (0.7 mu m < PM < 1.1 mu m), respectively. The relative contribution of most abundant sources was 32.4% of long-range transport source in the coarse particle mode and 34.5% of secondary aerosol in the fine particle mode, respectively. It seems that the size-resolved analysis by PMF provides useful information on controlling local/regional emission sources and on acquiring scientific knowledge for size-resolved aerosol compositions emitted from specific sources.