What is the efficiency percentage of HEPA filters in removing particles 0.3 microns or larger?

HEPA filters are designed to achieve a high level of efficiency when it comes to filtering out airborne particles. The standard for HEPA (High-Efficiency Particulate Air) filters dictates that they must be capable of removing at least 99.97% of particles that are 0.3 microns in size or larger from the air that passes through them. This performance level is critical, as the 0.3 microns particle size is often referred to as the most penetrating particle size (MPPS).

The efficiency of 99.97% is significant in various applications, including in hospitals, cleanrooms, and other environments where the control of airborne contaminants is essential for health and safety. This high efficiency is what distinguishes HEPA filters from other types of filters, which may have lower performance ratings and cannot adequately trap as many small particles.

For this reason, the answer indicating that HEPA filters remove 99.97% of 0.3-micron particles is correct, reflecting the rigorous standards set for air filtration systems used in critical applications.