National Indoor Air Quality Awareness Month takes place each October. The term indoor air quality (IAQ) refers to the air in any type of built environment, and with Americans spending approximately 90% of their time indoors according to the U.S. Environmental Protection Agency (EPA), indoor air quality can have a significant impact on comfort, health and even productivity., , , , EPA warns that the concentrations of some indoor pollutants can be 2 to 5 times higher than typical outdoor concen.