关键词: 关键词：大气自净能力, 气象条件, 冷空气强度, 城市化, 夜间灯光指数

Abstract: Abstract: Based on the ground meteorological observation data of Hohhot station from 1981 to 2018, air quality data from 2014 to 2018 and nighttime light data from 1992 to 2013, the atmospheric self-cleaning ability index (ASI) was calculated, and the variation characteristics of atmosphere self-cleaning ability in Hohhot city in the past 38 years and its influencing factors were discussed.The results show that ASI was negatively correlated with air quality index (AQI), and the relationship between them could be expressed by a power function. The smaller the ASI was, the greater the risk of air pollution would be. The annual average ASI in Hohhot  declined significantly, especially after the 21st century. Compared to precipitation, wind speed and mixed layer height were more important to ASI. The positive correlation between the cold air active days and ASI was significant. After the 21st century, the cold air activity was obviously weak, which had a certain influence on ASI. The nighttime light index and the nighttime light area had a significantly negative correlation with ventilation. To some extent, the urbanization process played a role in the decline of ASI, especially after the 21st century.

Key words: Key words: atmospheric self-cleaning ability, meteorological conditions, cold air intensity, urbanization, nighttime light index