Indoor air can be 5 to 100 times dirtier than out door air quality and most people spend about 90 percent of their time inside. Common pollutants include dust mites, mold spores, pet dander, smoke and volatile organic compounds from household products and building materials. These contaminants can trigger allergies, asthma, headaches and other respiratory problems. Over time dust and debris also collect inside air ducts and circulate through your home. Having your ducts professionally cleaned helps remove built up contaminants and improves airflow. Professional air purification systems capture fine particles, reduce allergens and help create a healthier home. K