Optimum particle size for prediction of ambient air arsenic dry deposition in central Taiwan

This investigation monitors the concentrations of ambient air arsenic species (As, As(III) and As(V)) in total suspended particulates (TSPs) and dry deposits. Calculated/measured dry deposition flux ratios of ambient air arsenic species at five characteristic sampling sites in the years 2009-2010 are determined using two dry deposition models. An analysis reveals that the average concentrations of arsenic species in TSPs and dry deposits were highest at the Quan-xing sampling site, located in a severely polluted area where numerous industrial factories are located. The average seasonal concentrations of arsenic species in TSPs were highest in winter and fall in all instances. Analytical results reveal that low-wind conditions increased the concentrations of arsenic species in fall and winter at the five study sampling sites. Finally, Noll and Fang's model yielded the best predictions of the dry-deposited ambient air arsenic species (As, As(III), and As(V)) dry deposition for when the particles were larger than 5.6 μm, while Baklanov and Sorensen's model yielded the most accurate results when the particles were smaller than 5.6 μm.

► Characterize air arsenic species concentrations in TSP and dry depositions. ► Ambient arsenic species concentrations and dry deposition for seasonal variations. ► Using dry deposition model to estimate arsenic species at different particle size.