[Characteristics of PM Pollution in Beijing During the Historical Period of the 2022 Olympic Winter Games].

Based on the dataset derived from January to March between 2015 and 2021 in Beijing, the PM pollution characteristics and its potential source regions during the historical period of the Beijing 2022 Olympic Winter Games and Paralympic Winter Games were investigated. From 2015 to 2018, both the number of severely polluted days (daily average (PM)>75 μg·m) and the average PM concentrations during severe pollution episodes decreased significantly in the period of January to March. While, neither variable has changed obviously since 2018.