Air purification is attempting to remove impurities from the air. Two  common methods are High Efficiency Particulate Arresting (HEPA) or electrostatic air filters to clean the air; HEPA units effectively remove 99.97% of all pollen, dust, mold spores, dust mites, bacteria, and animal or bird dander that pass through the filter; electrostatic filtration cleans the air with charged .lates and saves the cost of replacement filters but requires that the plates be washed. The ventitlation system from Aerovex Systems called "The One That Works" is shown in the photo.