Ambient trace metals sources in Taichung, Taiwan: Principal component analysis

Abstract

There were eight trace metals, including As, Hg, Mn, Fe, Zn, Cr, Cu, and Pb, measured in the total suspended particles collected in central Taiwan using PS-1 samplers at five different sites. Overall, these trace metal concentrations were lower in summer than other seasons, and higher in industrial areas than in wetland. Principal Component Analysis (PCA) was utilized to identify the pollutant sources for each site. Three distinct sources were found in this study, and the results suggest that mobile sources were the main factor contributing to Mn, Fe, Zn, and Cr emissions, which were mainly from urban areas and in the vicinity of highways intersections. Within addition, municipal solid waste incinerators are significantly associated with emissions of As, Hg, Cu, and Pb. Finally, smelters were associated with high Hg, As, Fe, and Zn emissions from local industrial areas. However, contributions from two known point sources, a coal-fired power plant and a steeling plant could not be distinguished from the PCA results. This may be due to the prevailing wind directions and limitations of the measurements used in this work. These two sources are located to the west of these sampling sites, while the prevailing wind direction in this area was southwest. Copyright © Taiwan Association for Aerosol Research.