A dust mask or respirator is a mask worn over the mouth and nose to protect the wearer against the inhalation of dusk and other harmful particulates. This dust mask acts as a filter as the wearer breathes, the filter material porous enough to allow air to pass but not bigger particles. The mask may have a valve. Respirators are worn by, among others, people working in dusty environments (e.g. when sanding) and also by cyclists wishing to minimise the airborne pollutants from motor vehicles they might inhale on roads.

Dust masks are essential wear for workers installing fibreglass and offer protection when sanding and working with power tools, particularly on surfaces coated with dried paint where the dust formed may be toxic. Dust masks are commonly worn in agriculture as well where workers may come into contact with germs and spores, as well as pesticides and fertilisers.