Characteristics and recent trends of sulfur dioxide at urban, rural, and background sites in north China: effectiveness of control measures.
Characteristics and recent trends of sulfur dioxide at urban, rural, and background sites in north China: effectiveness of control measures.
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DOI：
10.1016/s1001-0742(11)60727-4
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发表时间：
2012
影响因子：
6.9
通讯作者：
Weili Lin;Xiaobin Xu;Zhiqiang Ma;Huarong Zhao;Xiwen Liu;Y. Wang
中科院分区：
文献类型：
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作者：
Weili Lin;Xiaobin Xu;Zhiqiang Ma;Huarong Zhao;Xiwen Liu;Y. Wang
通过对北京及周边地区近几年的SO2观测，研究了我国北方不同类型地面SO2的变化及趋势。SO2总平均浓度为（16.8 ± 13.1）ppb，（14.8 ± 9.4）ppb，（7.5 ± 4.0）ppb，中国气象局（CMA，北京市区），古城（GCH，相对污染的农村地区，北京市区西南110公里），以及上店子（SDZ，清洁本底区，北京城区东北100公里）。冬季（采暖季）SO2浓度比夏季高4-6倍。不同站点SO2日均值之间存在极显著的相关性，反映了SO2污染的区域特征。各站点地面SO2的日变化具有一个共同的特征，即白天有一个峰值，这可能是由于华北平原上空富SO2空气的向下混合和/或平流输送造成的。CMA和GCH的SO2浓度呈显著下降趋势（CMA为-4.4 ppb/yr，GCH为-2.4 ppb/yr），而SDZ的SO2浓度呈不显著下降趋势（-0.3 ppb/yr），反映了SDZ作为华北区域大气背景站点的特征。3个监测点的SO2浓度在2008年奥运会控制措施实施前后均有明显下降，表明SO2污染控制具有长期效果和效益。奥运后，CMA、GCH和SDZ的SO2平均浓度分别为（14.3 ± 11.0）ppb、（12.1 ± 7.7）ppb和（7.5 ± 4.0）ppb，与奥运前相比分别下降了26%、36%和13%。分析表明，气温、相对湿度、风速、风向等因素的差异不是导致奥运前后SO2浓度显著差异的主导因素。通过提取更能代表当地或区域特征的数据，获得了污染区SO2减少40%，区域SO2减少20%的奥运会控制措施的效果。
SO2measurements made in recent years at sites in Beijing and its surrounding areas are performed to study the variations and trends of surface SO2at different types of sites in Northern China. The overall average concentrations of SO2are (16.8 ± 13.1) ppb, (14.8 ± 9.4) ppb, and (7.5 ± 4.0) ppb at China Meteorological Administration (CMA, Beijing urban area), Gucheng (GCH, relatively polluted rural area, 110 km to the southwest of Beijing urban area), and Shangdianzi (SDZ, clean background area, 100 km to the northeast of Beijing urban area), respectively. The SO2levels in winter (heating season) are 4-6 folds higher than those in summer. There are highly significant correlations among the daily means of SO2at different sites, indicating regional characteristics of SO2pollution. Diurnal patterns of surface SO2at all sites have a common feature with a daytime peak, which is probably caused by the downward mixing and/or the advection transport of SO2-richer air over the North China Plain. The concentrations of SO2at CMA and GCH show highly significant downward trends (−4.4 ppb/yr for CMA and −2.4 ppb/yr for GCH), while a less significant trend (−0.3 ppb/yr) is identified in the data from SDZ, reflecting the character of SDZ as a regional atmospheric background site in North China. The SO2concentrations of all three sites show a significant decrease from period before to after the control measures for the 2008 Olympic Games, suggesting that the SO2pollution control has long-term effectiveness and benefits. In the post-Olympics period, the mean concentrations of SO2at CMA, GCH, and SDZ are (14.3 ± 11.0) ppb, (12.1 ± 7.7) ppb, and (7.5 ± 4.0) ppb, respectively, with reductions of 26%, 36%, and 13%, respectively, compared to the levels before. Detailed analysis shows that the differences of temperature, relative humidity, wind speed, and wind direction were not the dominant factors for the significant differences of SO2 between the pre-Olympics and post-Olympics periods. By extracting the data being more representative of local or regional characteristics, a reduction of up to 40% for SO2 in polluted areas and a reduction of 20% for regional SO2 are obtained for the effect of control measures implemented for the Olympic Games.