We spend about 90% of our time indoors and all this gets breathed into us and our children. Air pollutants can and do cause allergies, sick building syndrome, bacterial infections and spread viruses to name a few. The American College of Allergists state that 50% of all illnesses are caused by polluted indoor air. They state that 10 to 12 million people in the US suffer from asthma and that asthma is the single largest cause of hospital visits by children.