| Summary: | 碩士 === 國立中興大學 === 環境工程學系 === 87 === The purpose of this study was to determine the characteristics and the affecting factors on the airborne dust concentrations from the paved roads in Taichung urban area. The dust emission factor was established and the efficiency of vacuum sweeping the road dust were also assessed in this study. Several experiments were conducted from March 1998 to April 1999. The measurement included TSP concentration, traffic flow rate, wind speed (U) and the silt loading (SL). Mass balance method was used to determine the particulate emission factor from a paved road. The results indicated the particulate concentrations were welled correlated with traffic flow rate, silt loading and wind speed with the correlation coefficients 0.98, 0.86 and 0.89, respectively.
The determined particulate emission factors from the paved road were 0.69±0.36 g/VKT with approximately 12 % of the emissions contributed from the vehicular exhaust. The emission factor EF was determined as EF = 0.47 U0.81 SL0.35, which was about 8 times lower than the AP-42 suggested value. It indicated that the emission inventory might overestimated the emissions from the paved road. Based on these studies, the annual TSP emissions from paved road in Taichung City was approximately 2660 tones, which was equivalent to 9 % of the total emissions this city.
Furthermore the study also evaluated the silt loading on 12 main roads in Taichung City. The total surface loading ranged from 2.0 g/m2 to 9.6 g/m2 and the silt loading ranged from 0.3 g/m2 to 1.0 g/m2 which was equivalent to 5~12 % of the road dust. The experimental runs also showed approximately 31±17 % reduction in TSP concentrations near road-side after dust-removal by vacuum sweeping truck, which was equivalent to 3 % reduction on ambient TSP concentration.
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