A dust mask is a flexible paper pad held over the nose and mouth by elastic or rubber straps for personal comfort against non-toxic nuisance dust.
When used properly, dust masks prevent the inhalation of dust in the air and protect the lungs. When you inhale, the air is pulled through the dust mask, and dust is captured on the outside of the mask. Dust masks will leak if they don’t fit your face properly. Dust masks don’t filter out chemical vapors.