空气重污染应急措施对北京市PM2.5的削减效果评估

利用嵌套网格空气质量模式系统(NAQPMS)模拟了2013年1月10~14日一次典型的大气严重污染过程,并利用同期气象和污染物浓度的小时观测数据验证了NAQPMS的模拟结果.敏感性试验结果表明,在重污染期间,当仅实施《北京市空气重污染应急预案(试行)》一级预警中机动车单双号限行措施时,可削减北京PM2.5小时平均浓度4%~10%;当仅实施工业限产减排30%的措施时,可削减北京PM2.5小时平均浓度1%~6%;当同时实施机动车单双号限行和工业限产减排30%的措施时,可削减北京平均PM2.5小时平均浓度6%~12%,并且PM2.5小时浓度与削减率的变化趋势呈反相关,即该措施对污染较轻时段PM2.5浓度削减率高于污染峰值时段;若京津冀地区两市一省同时实施机动车单双号限行和工业限产减排30%的措施时,可削减重污染期间北京小时平均PM2.5浓度20%~35%,且污染严重的区域和时段削减效果更加显著,空气质量可提升一个等级.研究结果表明,当北京发生重污染时,仅靠北京本地限排限产并不能有效减轻PM2.5浓度,若要有效控制北京重污染,应根据污染物区域输送特征,京津冀地区实施大气污染联防联控.

A model evaluation of the effect of implementing heavy air pollution emergency plan to PM2.5 reduction in Beijing

The nested air quality prediction model system (NAQPMS) was utilized to simulate a severe polluted process from January 10th to 14th, 2013. NAQPMS reproduced the variation of pollutants well, with good agreement between model simulation and observations both in tendency and magnitude. The sensitivity tests indicate that PM2.5 would be reduced by 4%~10%, 1%~6%, and 6%~12%, respectively, if the odd-even traffic control measure, the 30% industrial emission cut measures were implemented separately, or simultaneously. It was found that PM2.5 concentration was inversely correlated with its reduction ratio in the above three tests, in other words, the reduction ratio of the above measures taken in Beijing was much higher in the periods of low PM2.5 concentration. If both of the above measures were taken simultaneously over Hebei-Beijing-Tianjin (HBT) region, it would lead to 20%~35% reduction in PM2.5 concentration and air quality would be improved by one level higher, especially during the periods in areas of peak concentration. In summary, it was unreliable to limit local emissions exclusively for controlling heavy pollution of Beijing, and the combined effort in control of HBT could be a better way to solve the emergent air pollution problem in Beijing.