Reduces up to 95% of airborne particles catching pollutants such as Smog, pollen, smoke, pet dander, mold spores, and fine dust as small as 1 micron. MERV 13 at a minimum is 50% efficient at capturing particles with diameters between 0.3 microns and 1 micron and provides a superior level of filtration and protection from particles that cause asthma and other air quality related afflictions at a greater efficiency than MERV 11. Many types of bacteria and large sized viruses are also captured at this level of filtration efficiency, improving indoor air quality and protecting your health.