Abstract. Daily air concentrations and dry deposition fluxes of seven metal species were monitored at five sites in central Taiwan for five or six days every month from September 2009 to August 2010. Annual average concentrations at the five sites were in the range of 2.8 to 3.6 ng m−3 for As, 25 to 82 ng m−3 for Mn, 1900 to 2800 ng m−3 for Fe, 69 to 109 ng m−3 for Zn, 18 to 33 ng m−3 for Cr, 60 to 110 ng m−3 for Cu, and 25 to 40 ng m−3 for Pb. Annual average dry deposition fluxes were on the order of 3, 20, 400, 50, 25, 50, and 50 μg m−2 day−1 for As, Mn, Fe, Zn, Cr, Cu, and Pb, respectively. Annual average dry deposition velocities (Vd) for the seven metal species ranged from 0.18 to 2.22 cm s−1 at these locations. Small seasonal and geographical variations, e.g. from a few percent to a factor of 2 for different species and/or at different locations, were found in the measured concentrations, fluxes, and Vds. The measured fluxes and air concentrations had moderate to good correlations for several of the species at several of the sites (e.g. Fe, Zn, and Mn at most of the sites), but had either weak or no correlations for the other species or at the other sites (e.g. As at Sites I and III, Zn and Cr at Site IV, and Cu at most of the sites). The latter cases were believed to have large uncertainties in the flux measurements using surrogate surfaces. Sensitivity tests were conducted for particle Vds using a size-segregated particle dry deposition model, assuming various combinations of three lognormal size distributions representing fine particles (PM2.5), coarse particles (PM2.5–10), and super-sized particles (PM10+), respectively. It was found that the measured dry deposition fluxes can be reproduced reasonably well using the size-segregated particle dry deposition model if the mass fractions of the metal species in PM2.5, PM2.5–10 and PM10+ were known. Significant correlations between the modeled and the measured daily fluxes were found for those cases that were believed to have small uncertainties in the flux measurements.

Daily air concentrations and dry deposition fluxes of seven metal species were monitored at five sites in Central Taiwan for five or six days each month from September 2009 to August 2010. Annual average concentrations at the five sites were in the range of 2.8 to 3.6 ng m⁻³ for As, 25 to 82 ng m⁻³ for Mn, 1900 to 2800 ng m⁻³ for Fe, 69 to 109 ng m⁻³ for Zn, 18 to 33 ng m⁻³ for Cr, 60 to 110 ng m⁻³ for Cu, and 25 to 40 ng m⁻³ for Pb. Annual average dry deposition fluxes were on the order of 3, 20, 400, 50, 25, 50 and 50 μg m⁻² day⁻¹ for As, Mn, Fe, Zn, Cr, Cu and Pb, respectively. Annual average dry deposition velocities (<i>V</i>_d) for the seven metal species ranged from 0.18 to 2.22 cm s⁻¹ at these locations. Small seasonal and geographical variations, e.g., from a few percent to a factor of 2 for different species and/or at different locations, were found for measured concentrations, fluxes and <i>V</i>_d. Measured fluxes and air concentrations had moderate to good correlations for several species at several sites, but had weak or no correlations for other species or at other sites, the latter cases were believed to have large uncertainties in flux measurements using surrogate surfaces. Sensitivity tests were conducted for particle <i>V</i>_d using a size-segregated particle dry deposition model, assuming various combinations of three lognormal size distributions representing fine particles (PM_2.5), coarse particles (PM_2.5-10) and super size particles (PM₁₀₊), respectively. It was found that measured dry deposition fluxes can be reproduced reasonably well using the size-segregated particle dry deposition model if the mass fractions of metal species in PM_2.5, PM_2.5-10 and PM₁₀₊ were known. Significant correlations between modeled and measured daily fluxes were found for those cases that were believed to have small uncertainties in flux measurements

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