In the 1970s, energy conservation measures to combat the energy crisis resulted in the tightening of office building envelopes and the reduction of outdoor air ventilation rates. The result of that approach was a buildup of indoor pollutants and the emergence of “Sick Building Syndrome,” a collection of symptoms associated with inferior indoor air quality. According to the U. S. Environmental Protection Agency (EPA) the term "Sick Building Syndrome" (SBS) is used to describe situations in which building occupants experience acute health and comfort effects e.g., headache, eye, nose, or throat irritation, dry cough, dry or itchy skin, dizziness and nausea, fatigue and sensitivity to odors and inability to concentrate. The problem is also adversely affecting our children's health as millions of homes and apartments and one in five schools in America have indoor air quality problems. Most of the complainants report relief soon after leaving the building.