Fang Guor-Cheng, Wu Yuh-Shen, Huang Shih-Han, Rau Jui-Yeh
Air Toxic and Environmental Analysis Laboratory, Department of Environmental Engineering, Hungkuang Institute of Technology, Hungkuang University, Sha-Lu, Taichung 433, Taiwan.
Chemosphere. 2004 Aug;56(6):509-18. doi: 10.1016/j.chemosphere.2004.04.032.
Downward, upward dry deposition fluxes and total suspended particulate of particulate heavy metals (Fe, Pb, Zn, Cu, Mg and Mn) were measured in daytime and nighttime period in Sha-Lu, a small city in the central Taiwan during summer period of 2003. The results showed that the total suspended particulate concentrations of particulate mass in the daytime period (averaged 996.2 g/m3) were higher than in nighttime period (averaged 560.7 g/m3). And the downward dry deposition fluxes (averaged 54.07 g/m2s) were about two times as that of upward dry deposition fluxes (averaged 26.48 g/m2s) in the daytime period. Furthermore, the average downward dry deposition fluxes (averaged 26.22 g/m2s) were also about two times as that of upward dry deposition fluxes (averaged 12.11 g/m2s) in the nighttime period. In addition, the average downward dry deposition fluxes are greater than the upward dry deposition fluxes for all the heavy metals in either daytime or nighttime period. The proposed reasons are that the wind speed and concentration difference for daytime and nighttime period lead to these results at the traffic sampling site of central Taiwan. In addition, the deposition velocity for mass, heavy metals (Fe, Pb, Zn, Cu, Mg and Mn) during daytime and nighttime period were also calculated. The average daytime dry deposition velocity for downward particulate mass, upward particulate mass, Fe, Pb, Zn, Cu, Mg and Mn were 5.56, 2.66, 1.71, 0.18, 1.06, 0.24, 0.47 and 0.11 (cm/s), respectively. And the average nighttime dry deposition velocity for downward particulate mass, upward particulate mass, Fe, Pb, Zn, Cu, Mg and Mn were 4.70, 2.11, 1.66, 0.18, 0.86, 0.23, 0.32 and 0.07 (cm/s), respectively at traffic sampling site of central Taiwan.
2003年夏季，在台湾中部的小城市沙鹿，对颗粒态重金属（铁、铅、锌、铜、镁和锰）的向下、向上干沉降通量以及总悬浮颗粒物进行了白天和夜间的测量。结果表明，白天颗粒物质的总悬浮颗粒物浓度（平均996.2微克/立方米）高于夜间（平均560.7微克/立方米）。并且白天的向下干沉降通量（平均54.07微克/平方米·秒）约为向上干沉降通量（平均26.48微克/平方米·秒）的两倍。此外，夜间的平均向下干沉降通量（平均26.22微克/平方米·秒）也约为向上干沉降通量（平均12.11微克/平方米·秒）的两倍。另外，在白天或夜间时段，所有重金属的平均向下干沉降通量均大于向上干沉降通量。推测原因是台湾中部交通采样点白天和夜间的风速及浓度差异导致了这些结果。此外，还计算了白天和夜间时段质量、重金属（铁、铅、锌、铜、镁和锰）的沉降速度。台湾中部交通采样点白天向下颗粒物质、向上颗粒物质、铁、铅、锌、铜、镁和锰的平均干沉降速度分别为5.56、2.66、1.71、0.18、1.06、0.24、0.47和0.11（厘米/秒）。而夜间向下颗粒物质、向上颗粒物质、铁、铅、锌、铜、镁和锰的平均干沉降速度分别为4.70、2.11、1.66、0.18、0.86、0.23、0.32和0.07（厘米/秒）。
