Indoor Pollution

Officials at the Environmental Protection Agency (EPA) and others have long cited indoor pollution as one of the most serious environmental risks to public health. Indoor pollutants range from natural sources, such as radon gas, to commonly used consumer products, such as cleaners and solvents, to various household activities, such as cooking or smoking. Concentrations of pollutants in indoor air can exceed those found outside by a factor of two to five. Moreover, some vulnerable groups, such as the very young and the infirm elderly, spend as much as 90 percent of their time inside. Federal agencies report that they spent nearly $1.1 billion on indoor pollution research from 1987 through 1999. Research by the federal government and others has led to notable progress in understanding indoor pollution and in devising ways to mitigate the problem. Consumer products have been reformulated, and building materials and practices have been changed. However, many gaps in understanding the problem remain, including uncertainties about (1) the identity and the sources of pollutants; (2) the mechanisms by which people are exposed to them; (3) the health effects resulting from prolonged and intermittent exposure to low-level concentrations of chemical and biological pollutants as well as complex pollutant mixtures; and (4) the most cost-effective strategies for reducing pollutant sources, exposures, and consequent health effects.

GAO noted that: (1) the Environmental Protection Agency officials and others have consistently identified indoor pollution as one of the most serious environmental risks to public health; (2) pollutant exposures encountered indoors can result in some of the most serious pollutant exposures people receive as they go about their daily lives; (3) this is explained by the fact that concentrations of pollutants in indoor air can exceed those found in outdoor air by a factor of 2 to 5, by the sheer amount of time most people spend indoors, and by the peculiarities of the indoor environment; (4) federal agencies reported that they will have spent a total of almost $1.1 billion on indoor pollution-related research from fiscal years 1987 through 1999; (5) just over half of the agencies' actual and planned expenditures went for research related to indoor air, while about one-quarter went for research related to the hazard posed by lead in the indoor environment; (6) the remaining spending was for research relating to the hazards presented by radon and asbestos; (7) during this period, about 64 percent of the spending went for research conducted or sponsored by four institutes of the National Institutes of Health to provide a better understanding of the health effects associated with indoor pollution; (8) while some of the agencies have experienced an increase in indoor pollution-related research funding over this period, funding for such research has declined in other agencies, including the Department of Energy; (9) as a result of research funded by the federal government, a few state governments, and others since the early 1970s, notable progress has been made in understanding the problem of indoor pollution and in devising strategies for mitigating pollutant exposures; (10) consumer products have been reformulated, and building materials and practices have been altered; (11) guidance documents have also been developed for use by building managers, homeowners, and consumers to help them better understand the causes and the sources of indoor pollution and enable them to take steps to prevent pollution problems or remedy them when they occur; and (12) notwithstanding the progress that has been made in understanding and managing the problem of indoor pollution, GAO's review of the scientific literature as well as comments provided by agency officials and other experts clearly showed that many gaps in knowledge and understanding of the problem remain.