The abstract must be improved: It is a description of processes but not an abstract of the work presented in the paper. What are the objectives, measurement methods, data, analyses methods, new results and conclusions?
An analyses is missing in section 2 which data are required and why. It is necessary to show which data are available and which data are missing. It should be explained why the data basis is complete for this study

1. Grammatical error in Lines 20-22 need be modified.
2. "red line " in the description of Fig. 1 "The location of Beijing city in China" is inappropriate.
3. More studies on the association between circulation and PM2.5 pollution should be summarized in introduction or compared with results. (e.g. Leung et al., 2018, DOI: 10.5194/acp-2017-916; Liu et al., 2019, doi: 10.1007/s13351-019-9007-z).