The Research on The Dry Deposition of Sulfur Dioxide in The Loess Zone.

2000-2002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和甘肃兰州进行了SO2和O3干沉降速率的测量。在采样点的选择上，主要考虑以下几个方面：交通的便利性、便利性。材料供应、地面平整度、地形信息（如范围面积）、地表状况（包括植被）、二氧化硫基线浓度、代表性风速、平均温度、湿度等。在两个地点，采用气象梯度法和代表面法，分别在两个季节对实际土壤进行了沉降速率的测定试验由我们提出。尽管如此，北京和兰州都是黄沙受体区和空气污染城市， 关于我们 中国最早观测到了雾霾。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。在对两种方法估算的二氧化硫干沉降速度进行比较时，一般来说，梯度法比代表面法估算的干沉降速度要高。以兰州黄土为研究对象，在改变臭氧和湿度的单一和共存条件下，进行了室内二氧化硫暴露试验，并考虑到与现场测量结果的一致性数据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，沉积的二氧化硫被[S（IV）→S（VI）]氧化的比例有增加的趋势。硫氧化物的沉积速度随着湿度的增大而增大，在实际观测的干燥条件下，硫氧化物的沉积速度比干燥条件下的硫氧化物的沉积速度进一步降低。少

During fiscal 2000-2002, we measured dry deposition velocity of sulfur dioxide and ozone in Beijing and Lanzhou City, Gansu 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 both sites, measurement experiment of the deposition velocity was respectively carried out at two seasons using the meteorological gradient method and representative surface method using actual soil proposed by us. Still, both of Beijing and Lanzhou are yellow sand receptor region and air-polluted cities where the photochem … More ical smog was observed in China first. 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 representative surface 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 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. 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