The hoods and dust collectors remove the contaminants from the air. The amount left in the air around us is called the concentration. We use a respirator to eliminate or reduce the concentration in that air we breathe. We choose the respirator according to the type of contaminants it removes and by how much it will lower the concentration. Review the procedures at your plant for the election, distribution, fit testing and maintenance of the most used respirator at your plant.
Respirators do have limitations, however.
Of the particle-filtering type, all of the models, including the replaceable filter and reusable filter, can become clogged, making breathing difficult. If you notice this problem, have the filter changed. Particle-filtering respirators are not effective against vapors and gases. Hose masks supply noncompressed air through a large hose by a motor. Air-line devices move compressed air through a pressurized line.