... a melt-blown can effectively prevent most victims of below 5μm dust and a variety of respiratory pathogens2.Materials Non ... 15 minutes in the open burning after use 3 to 5 days , then rinse with water, It can be reused dried ... in the sun 5. Applicable Industry Paint, printing, welding, solvent occasion, health care, pesticides, laboratory, etc. activated carbon respirator(YH-074)