Nordic Pure 20x24x2 MERV 10 rated pleated AC air filters are made of electrostatically charged synthetic materials that attract and capture most airborne particulates in your home or office. Each time air passes through a Nordic Pure pleated furnace filter, lint, household dust, pollen, dust mites, pet dander, baking flour, mold spores and other contaminants are removed. Our treated synthetic filter media prevents the growth of bacteria or mold, resulting in a much healthier living space. MERV 10 air filters are comparable to air filters with the MPR rating of 800-1000, FPR rating between Green and Red, and APR rating between Gold and Platinum. Particles in indoor air are measured in microns, which are 1/1000 of a millimeter (a human hair is about 70 microns wide). Each Nordic Pure 2 MERV 10 air filter will capture more than 85% of 3.0-10.0 micron contaminants and up to 65% of 1.0-3.0 micron contaminants. This high performance HVAC replacement filter will outperform non-electrostatic fiber-glass filters, washable filters, poly disposable filters, and will help keep your air conditioning and heating systems running efficiently, saving you money on utilities and costly maintenance. The effective life of your air filter depends on both the inside and outside conditions in which you live. We recommend that you change your air filter every 30-90 days to maintain maximum efficiency and indoor air quality.