What do Air-Purifying Respirators (APRs) primarily do?

Air-Purifying Respirators (APRs) are designed to protect users by filtering contaminants from the air they breathe. They work by utilizing various filter types to remove harmful substances, such as dust, smoke, gases, and vapors, thus ensuring that the air entering the respirator is safe for inhalation. The primary function of APRs is to purify the ambient air, allowing the wearer to breathe more safely in environments where airborne hazards are present.

In contrast, other options do not align with the fundamental design and function of APRs. For instance, providing compressed air pertains to supplied-air respirators, which deliver breathable air from a cylinder or a stationary source rather than filtering existing air. Monitoring air quality typically involves equipment designed to detect and measure the concentration of various airborne contaminants rather than purifying air. Insulating against heat falls more under the purview of protective clothing or gear, which is designed to protect against thermal exposure rather than filtering air pollutants.