| Low-to-moderate nuisance dust | Sweeping ordinary household dust, handling non-hazardous powders, or brief dusty clean-up tasks. | Identify the material first; consider how much dust is generated, how long the task lasts, and whether ventilation or wet methods can reduce it. | For particles that are not oil-based, a properly fitted NIOSH-approved N95 filtering facepiece may be suitable when the hazard assessment supports it. | A simple face covering is not a certified respirator. N95 protection depends on a close facial seal and correct use. |
| Wood dust | Sanding, sawing, routing, or machining wood and composite wood products. | Check the wood and any coatings or treatments; assess airborne dust, task duration, and the effectiveness of local exhaust ventilation. | Use a NIOSH-approved particulate respirator selected for the measured or reasonably assessed exposure. N95 is a filter class, not a guarantee that every exposure is adequately controlled. | Some hardwood dusts are associated with nasal cancer risk. A respirator does not replace dust extraction and housekeeping controls. |
| Respirable crystalline silica | Cutting, grinding, or drilling concrete, masonry, stone, and some engineered stone products. | Determine whether silica is present and assess the task, controls, and airborne exposure. Under the U.S. OSHA construction silica standard, the PEL is 50 µg/m³ as an 8-hour TWA and the action level is 25 µg/m³ as an 8-hour TWA. | Follow the applicable silica standard and task-specific controls. Select the respirator and filter based on exposure and required assigned protection factor; an N95 may not provide sufficient protection for every task. | Use engineering controls such as wet cutting or effective local exhaust where required. Do not rely on a mask alone to control silica exposure. |
| Metal-containing dust | Grinding, sanding, or handling metal, painted surfaces, or metal-containing materials. | Identify the metal and coating (for example, whether lead or another toxic metal is present); assess airborne concentration and whether the process also creates fumes. | Choose a NIOSH-approved respirator based on the specific contaminant, exposure assessment, and applicable regulations. A high-efficiency particulate filter may be appropriate for particles, but it does not protect against gases or vapors. | Metal fumes and mixed exposures require a separate assessment. Lead work may be subject to specific regulatory requirements. |
| Asbestos-containing dust | Disturbing suspected asbestos-containing insulation, tiles, boards, or other building materials. | Do not assume material is safe based on appearance. Have suspect material assessed by qualified personnel before disturbance. | Do not use an ordinary dust mask as a substitute for regulated asbestos controls. Respirator selection and use must follow applicable asbestos rules and be handled by trained, qualified personnel. | Avoid disturbing suspected asbestos. Work may require containment, specialized procedures, and licensed professionals depending on local law. |
| High or unknown particulate exposure | Heavy dust-generating work, enclosed spaces, visible dust clouds, or tasks involving unknown materials. | Obtain a competent hazard assessment and, where needed, exposure monitoring. Check oxygen levels and any non-particulate hazards before selecting equipment. | A P100 filter is rated to remove at least 99.97% of airborne particles under NIOSH test conditions; it does not by itself determine whether the complete respirator is suitable. Select the respirator type and protection factor for the assessed conditions. | Air-purifying respirators are not for oxygen-deficient or immediately dangerous atmospheres. Unknown or potentially dangerous conditions require professional assessment and appropriate respiratory protection. |