Protective mask is a kind of respiratory protective equipment for the purpose of preventing the spread of certain respiratory infectious microorganisms and protecting the health of the body.When inhaling, the low pressure in the mask causes the airflow to enter the mask; when exhaling, the air pressure in the mask is higher than the ambient pressure, and the airflow is discharged through the mask. When the filter material of the mask meets the requirements of the standard and the mask is sufficiently close to the user's face, most of the inspiratory airflow will be filtered by the filter material.