On the history of indoor air quality and health

Indoor air is a dominant exposure for humans. More that half of the body's intake during a lifetime is air inhaled in the home. Thus, most illnesses related to environmental exposures stem from indoor air exposure. Indoor air was believed to be a major environmental factor for more than a hundred years, from the start of the hygienic revolution, around 1850, until outdoor environmental issues entered the scene, and became dominant around 1960. Main environmental issues today are outdoor air quality, energy use, and sustainable buildings, but not indoor air quality (IAQ). But, there is mounting evidence that exposure to IAQ is the cause of excessive morbidity and mortality. In developing regions indoor unvented burning of biomass for cooking is the cause of at least 2,000,000 deaths a year (mainly women and children), and in the developed world IAQ is a main cause of allergies, other hypersensitivity reactions, airway infections, and cancers. Cancer of the lungs is related to indoor radon and ETS exposure. Allergies, airway infections and sick building syndrome are associated with, e.g., "dampness", a low ventilation rate, and plasticizers. In the future more emphasis must be given to IAQ and health issues.