奥运前后北京及其周边大气六氟化硫浓度的变化

2008年6～9月,对北京、兴隆、廊坊、沧州、石家庄、涿州、保定和禹城等8个站点进行每日2次的空气样品采集,利用气相色谱法对样品中的SF6浓度进行分析,以期对华北地区大气SF6的浓度范围、空间分布及其变化规律进行初步探索.结果表明,北京及其周边大气SF6浓度分布存在空间差异,8个站点在采样期间的平均浓度分别为:(10.7±5.1)×10-12、(6.7±0.6)×10-12、(7.2±1.6)×10-12、(8.0±1.7)×10-12、(9.6±5.5)×10-12、(7.6±2.1)×10-12、(8.3±3.5)×10-12和(8.5±2.0)×10-12(V/V),区域平均浓度为8.3×10-12(V/V).华北地区SF6的浓度大小和变化幅度主要受人为排放源的影响,呈现出脉冲式排放.兴隆站可作为华北区域的本底站点,观测期间其SF6的浓度呈线性增加,增长速度远大于全球本底增长速度.奥运前后的各种减排措施对北京SF6的排放有一定影响.

Atmoshperic sulfur hexafluoride in Beijing and near cities during the summer of 2008

As a potent greenhouse gas, sulfur hexafluoride (SF6) has been measured during the summer of 2008. Air samples from eight sites of North China were collected twice daily, the distributed sites including urban, suburban and rural locations. They are Beijing, Xinglong, Langfang, Cangzhou, Shijiazhuang, Zhuozhou, Baoding and Yucheng. During the observing period, the average mixing ratio of SF6 for these sites were (10.7±5.1)′10-12、(6.7±0.6)′10-12、(7.2±1.6)′10-12、(8.0±1.7)′10-12、(9.6±5.5)′10-12、(7.6±2.1)′10-12,(8.3±3.5)′10-12 and (8.5±2.0)′10-12 (V/V), respectively. The regional mixing ratio was 8.3′10-12 V/V for the North China. The magnitude and variation of SF6 was mainly affected by the anthropogenic emission source with an impulse pattern. As there was no sign of notable SF6 emission in the influence area of Xinglong, the station can be qualified as a background monitoring site for North China. The observed growth rate of SF6 in Xinglong was higher than that of the global. Anyway, the activities for energy saving and emission reduction did debase the concentration of SF6 in Beijing during the Olympic time.