They are wearing cloth masks. They are much less effective than an N95, but they don't contribute to any kind of significant CO2 buildup:
https://intermountainhealthcare.org/blogs/topics/covid-19/2020/07/debunking-common-face-mask-misconceptions/#:~:text=Wearing%20a%20cloth%20mask%20will,up%20inside%20the%20mask.