Where can I buy a dust mask?

Dust masks are available in pharmacies. Dust mask is a necessary protective equipment for workers engaged in and exposed to dust. It is mainly used in the working environment with low concentration of harmful gas and steam and dust. The filter box contains only adsorbent or sorbent. Some filter boxes are also equipped with filter layers, which can prevent aerosols at the same time. Some military gas masks are mainly made of activated carbon cloth, or waterproof and oil-proof.