Modeling dry deposition of total particle mass in trafficked and rural sites of Central Taiwan

Dry deposition plates, PS-1, micro orifice uniform deposit impactor (MOUDI), Noll rotary impactor (NRI), and Universal sampler were used to measure dry deposition fluxes and ambient air particle concentrations during day and night periods at a trafficked and a rural sampling site in central Taiwan. The results indicate that dry deposition fluxes of total particle mass at the trafficked site are about 100 times higher than at the rural sampling site. Statistical results also proved that there are no significant differences for the coarse particle concentrations in the trafficked and rural sampling sites. MOUDI, NRI, and Universal sampler were used to estimate the dry deposition flux. The ratios of estimated/measured dry deposition flux of total particle mass in the trafficked area are better than for the rural sampling site. This is because the NRI sampler applied in the trafficked area. The Noll & Fang model-predicted dry deposition flux is more accurate than that predicted by the Sehmel & Hodgson model in both the traffic and rural sampling sites. The Universal sampler was applied in predicting dry deposition flux in the rural site. The results show that the Universal sampler is not a suitable device in predicting dry deposition because it can only collect particle sizes less than 10 mu m. However, this study indicates that NRI combined with the Universal sampler is useful in predicting particle mass dry deposition. (C) 1999 Elsevier Science Ltd.