What are the two broad categories of respirators?

The correct categorization of respirators into air purifying respirators (APR) and air supplied respirators (ASR) reflects a fundamental distinction based on how they protect the user from airborne contaminants.

Air purifying respirators work by filtering out pollutants from the air that the user breathes, making them suitable for environments where the contaminants are known and can be effectively filtered. Examples include masks with particulate filters, chemical cartridges, or combination filters. The effectiveness of these devices relies on both the specific filter used and the concentration of contaminants in the surrounding air.

On the other hand, air supplied respirators provide clean air from an external source, such as a tank or a compressor. These are essential in situations where the air quality is too poor for air purifying respirators to offer adequate protection, such as in high-risk environments with toxic gases or insufficient oxygen levels.

Understanding these two categories is crucial for selecting the appropriate type of respirator based on the specific hazards present in the workplace, thus ensuring the health and safety of the individual using it.