Abstract
This study employed the method, which we have developed for determining trace metal elements in nano (0.030-0.108 μm), submicron (0.108-1.000 μm) and micron (1.000-9.970 μm) airborne particulates collected by electrical low pressure impactor (ELPI) using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The calibration curves showed good linearity in the range of 0.9526 (69Ga)-0.9994(27Al), and RSD for seven replicates of standard filter were below 18%. Furthermore, comparison of correlation between ELPI/LA-ICP-MS and Dicho/ICP-MS proved reliability of the proposed method and had extremely practical value. The proposed analytical method was applied to determine elemental concentrations of nano, submicron and micron particles collected at Hsinchu Science Park (HSP). Total of 27 elements, including Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Rb, Se, Sr, Ag, Cd, In, Cs, Ba, Tl and Pb were determined in this work. The result showed that at HSP was possibly responsible for As and Si in fine particles (<1μm). Annual trends of Pb, Cu, V, As, Cd and Tl have increased gradually, indicating that air pollutions at HSP became more serious from 2007 to 2010. Ambient mean As concentrations measured at HSP are all below the limited value (6ng/m3). However, 27 out of 99 measured As data were higher than the limited values with a 26.0 ng/m3 maximum concentration found in the year of 2009. On the other hand, the highly concentrated Ga, In and Tl in submicron particles might pose a potential health risk to the surrounding public. Asian dust (AD) storm are known to be a major air pollution source, which have strongly affected the atmospheric environment in many aspect. Aerosol samples were collected at national experimental high school from March 17 to 24, 2010. The result showed that most major elements, including Na, Mg, Al, Si, Fe, K and Ti distributed in not only micron fraction but also submicron fraction, which were carried by the storm. Submicron contributions of Zn, Cu, V, Pb, As and Cd descend significantly during AD episode while micron contribution is increased. Furthermore, we believed that several HSP related elements such as Tl, Rb, Cs, Co, Ga and Ag in micron fraction were also associated with dust storm, which suggest that dust storm not only deliver large amounts of crustal elements but also contribute significant amounts of toxic pollutants from foreign regions.