What is the size requirement for HEPA filter dust?

HEPA (High-Efficiency Particulate Air) filters are designed to capture a wide range of airborne particles, but they are especially effective at filtering out very small particles. The size requirement for HEPA filters is specifically set at 0.3 microns. This size is based on the most penetrating particle size (MPPS), which refers to the size of particles that are most difficult for the filter to capture. The efficiency of HEPA filters is defined as being able to trap at least 99.97% of particles at this size when tested under specific conditions.

Particles that are smaller or larger than 0.3 microns can still be captured effectively, but 0.3 microns is the standard reference point that determines the filter's overall efficiency. Thus, the specification of 0.3 microns is crucial for understanding how well HEPA filters perform in environments where controlling airborne contaminants, such as lead dust, is necessary for health and safety regulations.