What is the HEPA filter's rating for removing particles down to a certain micron size?

The HEPA filter, which stands for High-Efficiency Particulate Air filter, is specifically designed to capture a high percentage of very small particles from the air. The standard for HEPA filters is to remove at least 99.97% of particles that are 0.3 microns in size. This particular size is crucial because it represents the most penetrating particle size (MPPS) – particles of this size are the hardest to capture.

When a HEPA filter can efficiently trap 0.3-micron particles, it typically also captures a greater percentage of larger and smaller particles. Therefore, the ability of a HEPA filter to achieve this level of efficiency at 0.3 microns makes it suitable for applications involving air quality control, including in environments where mold spores, dust pollen, and other allergens are prevalent.

This highlights the effectiveness of HEPA filters in maintaining clean air, particularly in settings that require strict contamination control, such as in restoration work following water damage or in medical facilities.