Find the source of your contaminants. Indoor air pollution is quickly becoming a top environmental concern. If you're looking to purchase a home air purifier, one of the first things you should do is determine where the pollutants are coming from. Do you live with a smoker and need to get rid of tobacco smoke odors? Do you have pets and need to filter out pet dander? Is pollen making your allergies worse? Each one of these pollutants is best addressed by certain air purification methods, so find out where your contaminants are coming from. 

Determine what filtration methods you need. As a general rule, HEPA air purifiers are versatile and will work for most indoor pollution issues. HEPA filters boast 99.97% efficiency down to 0.3 microns or 1/100th of a human hair! Look for a HEPA air cleaner if you have a problem with pollen, pet dander, or dust. To get rid of odors, gases, or smoke, look for an air purifier with activated carbon. For mold, mildew, or other biological contaminants, a UV air purifier would be your best bet.

Learn what CADR means. CADR stands for Clean Air Delivery Rate. This is a certification program developed by the Association of Home Appliance Manufacturers (AHAM) to help consumers choose air purifiers. CADR is based on the cubic feet of air an air cleaner can filter per minute. The higher the CADR number, the faster and more efficient the air purifier will be at cleaning your air.