Clarification of Dry deposition of Suifer dioxide to Basic Soils and Estimation of Its deposition amount

2003-2005年，我们与中日环境保护友谊中心和中国环境科学研究院的海外合作研究人员在北京、兰州和大同等地进行了SO2和O3干沉降速率的测量。在选择取样地点时，考虑了以下项目：交通便利、材料供应方便、地面平整、范围面积等地形信息、包括植被在内的地表条件、二氧化硫基线浓度、代表风速、平均温度、湿度等。采用气象梯度法和我们提出的实际土壤被动法（代表面法），分别在一个季节和两个季节进行了沉积速度的测量试验。尽管如此，北京和兰州仍然是黄沙的接收区和空气污染的城市， 关于我们 在中国观测到了光化学烟雾。用气象梯度法计算了SO2和臭氧在黄土中的干沉降速率。采用代表面法得到了二氧化硫的沉降速度。为明确二氧化硫干沉降速率的控制因素，在臭氧、氮氧化物、硝酸、甲醛等单一和共存条件下，对兰州黄土进行了二氧化硫干沉降速率的实验室暴露试验，结果表明，梯度法估算的干沉降速率高于被动法，考虑到与现场测量数据的一致性，湿度发生了变化。虽然臭氧的存在并没有改变二氧化硫的沉积速度，但对沉积硫化合物的分析结果表明，随着臭氧浓度的增加，[S（IV）- S（VI）]对沉积二氧化硫的氧化作用所占的比例有增加的趋势。在干燥条件下，硝酸或甲醛的共存使二氧化硫的沉积速度降低到更小，而硫氧化物的沉积速度随着湿度的增加而增加，在干燥条件下如实际观察，其沉积速度比湿度更低。少

During fiscal 2003-2005, we measured dry deposition velocity of sulfur dioxide and ozone in Beijing, Lanzhou, and Daton in China with the overseas cooperative researchers belong to Sino-Japanese Friendship Center for Environmental Protection and Chinese Research Academy of Environmental Sciences. In the selection of sampling sites, the following items were considered ; Convenience of the traffic, convenience of the material supply, flatness of the ground, terrain information such as the area of the extent, earth surface condition including the vegetation, base line concentration of sulfur dioxide, representative wind velocity, mean temperature, humidity, etc. In their sites, measurement experiment of the deposition velocity was respectively carried out at one or two seasons using the meteorological gradient method and passive method (representative surface method) using actual soil proposed by us. Still, Beijing and Lanzhou are yellow sand receptor region and air-polluted cities where … More the photochemical smog was observed in China. Thus, we can examine the dry deposition of the ozone to the loess with it of sulfur dioxide.The dry deposition velocity of sulfur dioxide and ozone was obtained by the meteorological gradient method. Still, the deposition velocity of sulfur dioxide was obtained with representative surface method. In comparison of dry deposition velocity for sulfur dioxide estimated the above two methods, generally, the gradient method gave higher velocity than the passive method.In order to clarify control factor of the deposition velocity, laboratory exposure experiment of loess collected in Lanzhou to sulfur dioxide was carried out under single and coexistence condition of the ozone, nitrogen oxide, nitric acid, formaldehyde, and humidity changed considering the consistency with the field measurement data. Though the sulfur dioxide deposition velocity did not change by the coexistence of the ozone, as a result of the analysis of depositing sulfur compound, the proportion that oxidation of [S(IV)- S(VI)] for deposited sulfur dioxide was done tended to increase, as the ozone concentration is higher, more. In the dry condition, coexistence of nitric acid or formaldehyde caused to decrease the deposition velocity of sulfur dioxide to less. The deposition velocity of sulfur oxide increased, as the humidity is higher, and under the drying condition such as the actual observation, it became low deposition velocity further than the humidifying. Less