For the new coronavirus you can use particulate protection masks with better protection effect, such as 3M masks and N95 masks. When virus-carrying droplet nuclei exist in the air as particulate matter, particulate matter protective masks are comparable to medical protective masks in their blocking ability and can be used for self-protection in crowded places.
If the wearer does not carry pathogens, it is more comfortable to choose a mask with an exhalation valve. For the general population in places that are not densely populated, when there are no confirmed or suspected patients, ordinary medical surgical masks can be used and can also play a preventive role.