What mask should I wear in foggy days?

First, domestic PM2.5 is mostly dry particles, so you can consider buying NIOSH N-standard masks, such as N95. Of course, you can choose the P series. If you find it difficult to breathe with N95, please try wearing KN90 mask.

Second, cartoon masks can be described as "useless", and gauze masks cannot filter PM2.5；;

Thirdly, N95 masks also have a service life, generally 40 hours or 1 month, and cannot be washed;

Fourth, not everyone is suitable for wearing N95, and it is recommended that the elderly and pregnant women do not use it.