Dry depositions study for semi-open/outdoor environments at a concrete processing factory in ChangHua Coastal Park

Abstract

This study consisted of the collection and comparison of ambient air total suspended particulates (TSP), PM10, PM2.5 concentrations and dry depositions for semi-open/outdoor environments at a concrete processing factory in ChangHua Coastal Park during the year of 2017 (half-year observation). This study aimed to find the appropriate dry deposition models in the prediction of the semi-open/outdoor dry depositions for this factory. The results indicated that the average TSP, PM10, PM2.5 concentrations in the semi-open environment were all higher than those of the outdoor environment at this concrete processing factory, and the average dry depositions at the outdoor environment were all higher than those from the semi-open environment. A possible reason for this is the lack of any ventilation instrument during the processing period at the semi-open environment. In addition, the factory’s storage area opened directly to the outdoor environment. Ambient air particles were easily suspended in the atmosphere by the high frequency of passing trucks. Thus, high ambient air dry depositions particulates were measured at the outdoor environment. 20 and 23 μm particle sizes were selected as the calculated dry depositions velocities to obtain the calculated dry depositions fluxes for both the Baklanov and Wood models in this study. The above results showed that they exhibited better dry depositions prediction results for estimating outdoor and semi-open environments at this industrial concrete processing factory. Moreover, when comparing the above two models of dry depositions prediction performance, the Wood model exhibited better than the Baklanov model. Finally, this study also indicated that the ambient air particles moved from southeast to northwest Taiwan from July to December. In addition, PM2.5 and PM10 particles concentrations gradually increased from summer through autumn and winter season.