Not recommended for protection against gases unless specified. Will be expensive to repair. Possible lengthy repair period. Air-purifying respirators remove contaminants from the air but can be used only in an environment that has enough oxygen to sustain life. Do not use air purifiers to provide protection from the dangers of oxygen-limited environments.
Respirators are effective only up to their specified concentration limits.
The composition of a respirator's filter depends on the contaminant to be filtered. Various chemicals are used to remove gases and vapors. The useful life of the respirator is determined by the contaminant concentration, breathing volume of the wearer and capacity of the air purifying medium. Mechanical filters provide protection against particulates such as dusts, mists or metal fumes. A fibrous material in the filter traps the particles.