Suggested applications: welding, soldering, grinding, sanding, sweeping, bagging and other dusty or arid operations. Respirators with valves are ideally suited for work settings that involve heat, humidity, or long periods of wear. *3M recommended for relief against nuisance levels of organic vapors. Nuisance level refers to concentrations less than the OSHA PEL or applicable government occupational exposure limits, whichever is lower. **3M recommended for relief against nuisance levels of acid gases. Nuisance level refers to concentrations not exceeding OSHA PEL or applicable government occupational exposure limits, whichever is lower.