2020年春节期间京津冀及周边地区2次大气重污染过程分析

基于环境空气质量监测数据、天气实况资料、能源与主要大气污染物排放量数据,分析了2000年以来我国主要大气污染物的排放量和能源结构的演变,讨论了我国申请排污许可证企业主要污染物允许排放量空间分布,揭示了2020年1月下旬—2月中旬京津冀及周边地区发生的2次大气重度污染过程的形成原因。结果显示:全国取得排污许可证的企业中,73%的VOCs排放企业、62%的NO_x排放企业、48%的颗粒物排放企业聚集在京津冀及周边地区,密集的排放源为重污染形成提供了充分的污染物和前体物;气象条件对2次典型大气重度污染过程起着至关重要的作用,第一次(1月25—28日)是高压主导型的污染过程,高压抑制了污染物水平扩散,同时大气低层有逆温,抑制了污染物垂直扩散;第二次(2月9—13日)是低压前部型污染过程,由于地面伴有弱低压,并有较强逆温,抑制了污染物扩散;烟花爆竹燃放对PM_2.5浓度的影响基本只有5~10 h,对2次重度污染过程的影响有限。京津冀及周边地区改善环境空气质量任重道远,提出科学的大气污染防治政策,研发适宜的污染防治技术,采取可持续的措施与行动,完善相关标准体系等是真正实现大气环境质量改善的关键。

Analysis of two atmospheric heavy pollution processes in Beijing-Tianjin-Hebei and surrounding areas during the Spring Festival of 2020

Based on the monitoring data of ambient air quality, weather observation data, and the data of energy consumption and main atmospheric pollutants emission, the evolution of main pollutants emission and energy structure in China since 2000 was analyzed. The spatial distribution of allowable emission of main pollutants of enterprises which applied for emission permits in China was discussed, and the two serious pollution processes occurred in Beijing, Tianjin, Hebei and surrounding areas from late-January to mid-February 2020 were studied and revealed. The results showed that among the enterprises that had obtained emission permits, 73% of VOCs emission enterprises, 62% of NOx emission enterprises and 48% of particulate matter emission enterprises were concentrated in Beijing-Tianjin-Hebei region and its surrounding areas. The dense emission sources provided sufficient pollutants and precursors for heavy pollution. Meteorological conditions played an important role in the two typical heavy pollution events. The first heavy pollution case (January 25-28) was dominated by high pressure, which restrained the horizontal diffusion of pollutants, while there was inversion in the lower atmosphere, which restrained the vertical diffusion of pollutants. The second heavy pollution case (February 9-13) was located in front of low pressure, which restrained the diffusion of pollutants due to the weak low pressure and strong inversion on the ground. The impact of setting off fireworks on PM2.5 concentration was basically only 5 to 10 hours, and this impact on the two pollution process was limited. At present, there is a long way to go to improve the ambient air quality in Beijing-Tianjin-Hebei region and the surrounding areas. For the improvement of the air quality, it is vital to put forward scientific and reasonable air pollution prevention and control policies, research and develop appropriate pollution prevention and control technologies, take practical and sustainable measures and actions, and improve relevant standard systems.