To understand the complicated relationships between synoptic forcing, regional transport and aerosol pollution during the same period of the Beijing Olympic and Paralympic Winter Games in history from 2015 to 2019, long-term meteorological observations, aerosol measurements and radiosonde data in Beijing and Zhangjiakou were analyzed, in combination with numerical simulation and objective synoptic classification. It’s found that the heavy aerosol pollution in both Beijing and Zhangjiakou is associated with warm, moist, and calm wind situations at the ground level. At the upper level, the heavy pollution events in Beijing are related to the 850 hPa southwest winds, and the heavy pollutions in Zhangjiakou are typically associated with the southwest and south winds. Although the distance between the centers of Beijing and Zhangjiakou is around 160 km, the increasing aerosol concentrations and occurrence of thermal inversion aloft are often synchronously observed in those two cities, which are relevant to certain large-scale synoptic patterns. When there is a high-pressure system in eastern China at the 850 hPa level, the warmer air mass in the southern regions can be brought to Beijing and Zhangjiakou, enhancing the thermal inversion and suppressing the development of boundary layer to some extent. Meanwhile, the aerosols emitted from the south Hebei, the north Shanxi and middle Inner Mongolia can be transported to Beijing, leading to the exacerbation of pollution. With a higher altitude, the polluted air masses advected to Zhangjiakou are mainly from the western upstream regions, which can deteriorate the air quality in addition to the local emissions. Thus, under the unfavorable synoptic conditions, joint efforts to reduce emissions in Beijing, Zhangjiakou, and those upstream regions should be considered to effectively mitigate the heavy pollution.

通过分析北京和张家口地区长期地面气象资料、气溶胶浓度数据和探空数据, 研究冬奥会和冬残奥会历史同期(2015—2019年的2月1日至3月20日)的气象条件和气溶胶污染过程, 并利用数值模拟和客观环流分型方法, 探究高空环流和区域输送的影响。结果表明, 北京和张家口两地的气溶胶污染过程与近地面的暖、湿和小风条件有关。在850 hPa高度, 当两地受西北风影响时, 近地面的气溶胶浓度较低。北京的重污染过程主要与850 hPa高度的西南风有关, 张家口的重污染则主要与850 hPa高度的西南风和南风有关。虽然北京与张家口两市中心相距160多公里, 但两地的气溶胶污染和位温垂直结构变化有很强的关联性。当华东地区存在较强的高压系统时, 来自京津冀以南地区850 hPa高度的暖空气会输送到北京和张家口, 使两地同时出现高空增温现象, 进而增强对流层下部的热力稳定度, 不利于边界层的发展和污染物的垂直扩散。此外, 当上述环流出现时, 河北南部、山西北部和内蒙古中部等地区排放的污染物会通过输送过程影响北京。张家口地区海拔较高, 除本地排放外, 影响其空气质量的污染气团主要来自西部的上游地区。因此, 当出现不利的高空环流形势时, 除需要控制本地的排放外, 还要考虑对上游地区施行协同减排措施。