Washington Asbestos Worker Practice Exam

The filtering efficiency of a high-efficiency particulate air (HEPA) filter is defined as the ability to remove particles from the air at a certain size and efficiency rate. Specifically, a true HEPA filter must be capable of capturing at least 99.97% of airborne particles that are 0.3 micrometers in diameter. This particular size is significant because it represents the most penetrating particle size (MPPS), meaning particles of this size are the most difficult to filter out.

The high efficiency is crucial in environments such as asbestos abatement, where the containment of hazardous particles is essential. HEPA filters are widely used in various applications, including air purifiers, vacuum cleaners, and in situations requiring stringent air quality controls.

While the other percentages represent various levels of filtration efficiency, they fall short of the established standard for HEPA filters, which is specifically set at 99.97%. This standard ensures that the filtration system meets the rigorous safety and health standards necessary for protecting workers from harmful airborne contaminants.