SO 2 measurements made in recent years at sites in Beijing and its surrounding areas are performed to study the variations and trends of surface SO 2 at different types of sites in Northern China.The overall average c...SO 2 measurements made in recent years at sites in Beijing and its surrounding areas are performed to study the variations and trends of surface SO 2 at different types of sites in Northern China.The overall average concentrations of SO 2 are （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 SO 2 levels in winter （heating season） are 4–6 folds higher than those in summer.There are highly significant correlations among the daily means of SO 2 at different sites,indicating regional characteristics of SO 2 pollution.Diurnal patterns of surface SO 2 at all sites have a common feature with a daytime peak,which is probably caused by the downward mixing and/or the advection transport of SO 2 -richer air over the North China Plain.The concentrations of SO 2 at 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 SO 2 concentrations of all three sites show a significant decrease from period before to after the control measures for the 2008 Olympic Games,suggesting that the SO 2 pollution control has long-term effectiveness and benefits.In the post-Olympics period,the mean concentrations of SO 2 at 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 SO 2 between the pre-Olympics and post-Olympics periods.By extractin展开更多
基金supported by the National Basic Research Program of China (No.2005CB4222002)the National Natural Science Foundation of China (No. 20407001,40775074)+1 种基金the Basic Research Fund of CAMS (No. 2008Z011,2011CX001,2011Z003)the China Meteorological Administration(No. GYHY200706036,GYHY201106050)
文摘SO 2 measurements made in recent years at sites in Beijing and its surrounding areas are performed to study the variations and trends of surface SO 2 at different types of sites in Northern China.The overall average concentrations of SO 2 are （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 SO 2 levels in winter （heating season） are 4–6 folds higher than those in summer.There are highly significant correlations among the daily means of SO 2 at different sites,indicating regional characteristics of SO 2 pollution.Diurnal patterns of surface SO 2 at all sites have a common feature with a daytime peak,which is probably caused by the downward mixing and/or the advection transport of SO 2 -richer air over the North China Plain.The concentrations of SO 2 at 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 SO 2 concentrations of all three sites show a significant decrease from period before to after the control measures for the 2008 Olympic Games,suggesting that the SO 2 pollution control has long-term effectiveness and benefits.In the post-Olympics period,the mean concentrations of SO 2 at 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 SO 2 between the pre-Olympics and post-Olympics periods.By extractin
