In the past several years, many air filter firms began marketing co-called "Allergy Filters." In general these types of filters attempt to trap mold and spores. Most of these particles are three to ten microns in size. The more efficient the filter you use in your home, the greater the number of these particles it will remove. The MERV11 rated filter we offer traps over 90% of particles in this range. Remember, the MERV value is the air filter industry's standard for comparing filters. It is based on the minimum efficiency observed during the test of the filter. The test is a determination of the filter's ability to remove dirt, mold, and spores from the air we breathe. The higher the MERV rating the higher the percentage of particles removed. Fewer particles in the air can mean fewer allergy problems! The MERV11 rated filter is certainly one of the best choices an allergy sufferer can make.