I went to the airshow in 2016 and the air was quite alright. Changchun's supposed to have quite troublesome air quality in November though.I think the Airshow should be moved to Changchun since the air clarity is far superior up there. They should rename the show at Zhuhai a defense show instead.
It's really more about the design of the airport, where the runway is to the south of the hangers, which makes any footage shot from within the venue shooting against the sun. You really need to circumvate the roadblocks to the cropfields south of the runway before lockdown begins to get good footage and a good view of the airshow.