How small is 0.3 microns?
Very small! For comparison, household dust is 10 microns, a tobacco smoke particle is about 1 micron, and cat dander 5 microns. Pollen and mould spores are 30 microns in size, with a human hair at 40 microns. Remember, particles less than 10 microns in size are not visible to the human eye, but they are present in the air and can cause irritation. Honeywell True HEPA models help filter these pollutants from the air passing through the filter returning cleaner, fresher air to you.