제주시 도심지역에서 PM10과 PM2.5의 조성 특성

Abstract

Ambient PM10 and PM2.5 in this research was taken at 48-h or 72-h intervals at the downtown of Jeju City from October 2013 through February 2015. In this research, 23 elements and 8 soluble ionic species were determined using inductively coupled plasma-mass spectrometer (ICP-MS) and ion chromatographic system (IC). The objective of this research was to assess the composition and contents of soluble ions and metal elements in PM10 and PM2.5 and to identify the possible sources of ambient particulate matter using principal component analysis (PCA). The average concentrations of PM10 and PM2.5 in the downtown of Jeju City were 26.45 and 18.35 ㎍/m3, respectively. The ratio of PM2.5/PM10 was approximately 0.69. This result indicates that most of the PM10 is composed of PM2.5 and these particles may have similar sources. SO4 2-, NH4 + and NO3 - were the most abundant species in both of PM10 and PM2.5. These three species accounted for 80.3% and 92.4% of total ionic concentrations in PM10 and PM2.5, respectively. On the other hand, the contribution of other species (i.e., Na+, Mg2+, Ca2+, K+, Cl-) to total ionic concentration was very low in both of PM10 and PM2.5. From the ratio of PM2.5/PM10 for each ion species, SO4 2- and NH4 + was over 0.5, NO3 - show the value of 0.45, and Na+ and Cl- from sea salts and Mg2+ and Ca2+ from Soil exhibited values lower than 0.3. Based on total ionic concentration, the contribution of SO4 2-, NH4 + and NO3 - was 58.9% in the coarse fraction and 92.4% in the fine fraction, while that of the other ionic species such as Na+, Mg2+, Ca2+, Cl- was 38.8% in the coarse fraction and only 5.9% in the fine fraction. It was found that the concentration of elements such as Na, Ca, Al, Fe, K, Mg, Zn, Pb, and Mn contained in PM10 and PM2.5 were much higher than that of any other trace elements. Based on a simple comparison of the metal concentrations by their magnitude, the data sets can be arbitrarily grouped intotwo categories on the basis of the concentration of 10 ng/m3. The ratio of PM2.5/PM10 for Al, Ca, Fe, Mg and Na was lower than 0.35, while that for the other elements was higher than 0.5. By setting the arbitrary enrichment factor(EF) value of 10, several elements such as Sr, K, Ba, Ca, Mg, Mn contained in PM10 and PM2.5 had relatively lower EF values, while the anthropogenically-derived elements, including Se, As, Cu, Zn, V, Ni, Cd, and Cr, exhibited high EF values above 10. The results of the principal components analysis of the 18 metal elements and 4 ionic species were not readily interpreted. Nevertheless, five source categories of PM2.5 and PM10 provided the explanation for the data. About 71% of average PM10 was attributed to crustal material, fuel combustion such as coal, sea salts and resuspension dust, road dust and traffic-related particles, and secondary particles. Five principal components provided the explanation with about 72% of average PM2.5. These results indicated that secondary particles/fuel combustion processes, soil dust, sea salts/resuspension dust, and oil combustion/road traffic might be the sources of PM2.5.