A survey conducted in April 1999 by the American Lung Association revealed that 87% of homeowners are not aware that indoor air pollution may be more hazardous to their health than that found outdoors.
This lack of awareness is illustrated by the belief that unhealthy air can be avoided by staying inside homes and offices during "Code Red" days - days rated as unhealthy by the Environmental Protection Agency's Outdoor Air Quality Index. Americans spend 90% of their time indoors, according to the EPA. The EPA established indoor air pollution is one of the five most urgent environmental problems facing the United States.