Filtrete Ultimate Allergen filters are 93% effective at capturing large particles from the air that passes through the filter. They also remove much smaller particles, such as smoke, household dust, pet dander, bacteria and particles that can carry bacteria and tobacco smoke odors. The 3M Filtrete Ultimate filters have a 3M performance rating of 1900, The Performance Rating is a relative measure of a filter's efficiency at capturing airborne particles between 0.3 and 1 micron in size. The higher rating means better filtration efficiency based on independent laboratory tests of leading brands.

Note: Particles between 0.3 and 1 micron in size are classified as E1 particles by the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE). This is very similar to MERV ratings on other manufacturers filters.