Volume 3, No. 1, June 2003, Pages 29-39 PDF(142 KB)
Characteristics of Atmospheric Metals during Dry Monsoon Season in the Coastal Region of Western Taiwan
Hsi-Hsien Yang1, Pei-Chuan Chen1, Lien-Te Hsieh2, Min-Ching Lin1, Kuo-Lin Huang3
1 Department of Environmental Engineering and Management, Chaoyang University of Technology, Wufeng, Taichung 413, Taiwan
2 Department of Environmental Science and Engineering, Pingtung University of Science and Technology,1, Hseuh Fu Road, Neipu, Pingtung 912, Taiwan
3 Center of General Education, Chang Jung Christian University, Kway Jen, Tainan 711, Taiwan
This study investigated the characteristics (elemental concentrations, size distributions, and dry deposition flux) of aerosol particles in the coastal region of western Taiwan during the dry monsoon (fall and winter) season. Factor analysis results show that resuspended soil dust is a significant source of particles. However, factor analysis is unable to define specific emission sources of noncrustal metals, probably because these metals are mixed by long-distance transportation, regardless of their sources. On average, coarse mode particles (with aerodynamic diameters of larger than 1.0 μm) contribute 66% of the total particle mass. These coarse particles represent 53%, 64%, 62%, and 44% of the mass of elements Al, Ca, Fe, and Ti, respectively. Coarse particles predominate dry deposition fluxes because the average percentages of dry deposition fluxes attributed to fine particles are only 0.2%, 0.2%, 0.18%, 0.22% and 0.19% of the total particle mass, the Al mass, the Ca mass, the Pb mass and the Ni mass, respectively. Both atmospheric concentrations and dry deposition fluxes of Al, Ca, Fe, Mn and Sr are strongly influenced by crustal sources. For Pb, Zn, Ni, Ba, Cu and Cr, the parent aerosol is soil-oriented but the dry deposition is not. Neither the parent aerosol nor the dry deposition of V and Cd is influenced by crustal sources. Enrichment factors of most metal crust elements are considerably lower in dry deposition than in the parent aerosol. Fractionation factor analysis results show that the crustal component of a metal element in a parent aerosol is fractionated from the atmosphere by a dry deposition sequence. Although the noncrustal sources are not important in dry deposition, noncrustal elements can be easily fractionated between particles and dry deposits. Among the elements investigated, Pb had the highest fractionation factor of 12.1.
Metal; Size distribution; Dry deposition; Enrichment factor.