The 3M 9004 Is Composed Of Three Layers Of Filters. The Outermost Layer Filters Out The Largest Dust Particles, The Innermost Layer Preserves The Respirator S Shape And The Middle Layer Is Composed Of Electrostatic Filter MediaThese 3 Layers helps in Purifying the polluted air by upto 95%. The cool flow Valve makes it more comfortable while using it for long hours and warm/hot conditions.3M 8210 N95 Disposable Particulate Respirator is suggested for workplace applications such as grinding, sanding, sweeping, bagging and other dusty operations.The 8210 may also be used with Liquid or non-oil based particles from sprays that do not also emit harmful vapors. Also shall be used as a must having protective mask against dust / Flu -Recommended for H1N1 Swine flu / H5N1 Avian Bird Flu / SARS. This respirator does not supply oxygen. Do not use for paint spray, oil aerosols, vapors, asbestos or sand blasting.