HEPA stands for “High Efficiency Particulate air”. If you're looking for a filter than can get everything, this is it. Dustless HEPA filters are individually certified and serialized, meaning they've been laboratory tested to be compliant with OSHA and EPA laws for hazardous material containment. A Dustless HEPA filter captures 99.97% of particles at 0.3 microns. That is 0.00003 centimeters across, much smaller than the width of a human hair, a red blood cell, bacteria, pollen, and allergens.