These household odor and gas-reducing pre-filters are ideal for capturing harmful gasses such as ammonia and other volatile organic compounds. Pre-filters also perform exceptionally well in deodorizing the air and reducing odors with activated carbon and zeolite. Absorbing common household gasses and fumes, pre-filters will capture larger particles such as dirt, lint, fibers, and pet fur. It is recommended that you replace your filter every 3 months. This includes 1 pre-filter. It should be noted that tower air purifiers require 2 filters. Establish an unrivaled breathing experience for yourself and your loved ones with genuine filters.