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Common Terms Related to Respiratory Protection

  • Air purifying respirators are respirators equipped with an air-purifying filter, cartridge, or canister that removes specific air contaminants by passing ambient air through the air-purifying element
  • Cartridges and canisters are containers with a filter, sorbent, catalyst, or a combination thereof that removes specific contaminants from the air passed through the container. 
  • Filters are components used in respirators to remove solid particles from the inspired air. 
  • High efficiency particulate air (HEPA) filters are filters that are at least 99.97% efficient in removing monodisperse particles of 0.3 micrometers in diameter. The equivalent NIOSH (National Institute for Occupational Safety and Health) particulate filters are N100, R100, and P100 filters. 
  • IDLH (Immediately Dangerous to Life and Health) atmospheres are atmospheres that pose an immediate threat to life, would cause irreversible adverse health effects, or would impair an individual's ability to escape from a dangerous atmosphere.