Nearly 37 million people in China may have been infected with COVID-19 on a single day this week, Bloomberg News reported on Friday, citing estimates from the government's top health authority.
I’m not sure about air purifiers, but my impression is that China is really good about masks, mandate or no. They’ve already gone through a fairly recent airborne pandemic and it became a cultural norm to wear a mask when possibly sick.
More things to consider: are there mask mandates and are FFP2/3 level masks used? How widely air purifiers are used to reduce virus levels in air?
I’m not sure about air purifiers, but my impression is that China is really good about masks, mandate or no. They’ve already gone through a fairly recent airborne pandemic and it became a cultural norm to wear a mask when possibly sick.