
A face mask or respirator is a device designed to protect the wearer from inhaling hazardous atmospheres. These include fumes, vapours, gases and particulate matter such as dusts and airborne microorganisms. There are two main categories: the air-purifying respirator, in which respirable air is obtained by filtering a contaminated atmosphere, and [...]

Coronaviruses are a group of viruses that cause diseases in mammals and birds. In humans, coronaviruses cause respiratory tract infections that are typically mild, such as the common cold, though rarer forms such as SARS, MERS, and COVID-19 can be lethal. Symptoms vary in other species: in chickens, they cause an upper respiratory tract disease [...]