2018年春节期间京津冀地区污染过程分析

为了解2018年春节期间京津冀地区空气污染情况，利用近地面污染物浓度数据、激光雷达组网观测数据，结合WRF气象要素、颗粒物输送通量和HYSPLIT气团轨迹综合分析污染过程.结果表明，春节期间出现3次污染过程.春节前一次污染过程，各站点PM_2.5浓度均未超过200μg/m³；除夕夜，廊坊站点PM_2.5峰值浓度达到504μg/m³，是清洁天气的26倍；年初二~初五，各站点PM_2.5始终高于120μg/m³，且污染主要聚集在500m高度以下，北京地区存在高空传输，800m处最大输送通量达939μg/（m³·s），此次重污染过程为一次典型的区域累积和传输过程.京津冀地区处于严格管控状态时，燃放烟花爆竹期间PM_2.5峰值浓度可达无燃放时PM_2.5峰值的3.2倍.为防止春节期间重污染现象的发生，需对静稳天气下燃放烟花炮竹采取预防对策.

Analysis of the pollution process in the Beijing-Tianjin-Hebei region during the Spring Festival of 2018

In order to investigate the air pollution condition in Beijing-Tianjin-Hebei area during the Spring Festival in 2018, the pollution process was comprehensively analyzed by using near-surface pollutant concentration data and lidar observation data combined with WRF meteorological elements, particulate matter transport flux and HYSPLIT air mass trajectory. The results showed that there were three pollution processes during the Spring Festival. The concentration of PM_2.5 in each station did not exceed 200μg/m³ during the first pollution process before the Spring Festival. On New Year's Eve, the peak concentration of PM_2.5 at Langfang Station reached 504μg/m³, 26 times that of clean weather. From the second to the fifth day of the Lunar New Year, the PM_2.5 at each station was always higher than 120μg/m³, and the pollution was mainly concentrated below the height of 500 meters. There was high-altitude transportation in Beijing area, and the maximum transportation flux at 800 meters reaches 939μg/(m²·s). This heavy pollution process was a typical regional accumulation and transportation process. This study revealed that the Beijing-Tianjin-Hebei region is under strict control, and the peak concentration of PM_2.5 when fireworks are set off can reach 3.2 times of that when no fireworks are set off. In order to prevent the occurrence of heavy pollution during the Spring Festival, preventive measures need to be taken for setting off fireworks and firecrackers in stable weather.