Household Appliances Contribute to Indoor Air Pollution.

Environmental engineers from the University of Texas at Austin have documented that showers and dishwashers contribute to indoor air pollution. When tap water contains even trace amounts of harmful chemicals, such as radon, gasoline components, or by-products of chlorination, these chemicals can be transferred from water to indoor air through a process known as volatilization, or chemical stripping.

The researchers, led by Dr. Richard Corsi, associate professor of civil engineering, completed a series of experiments using household appliances such as dishwashers, clothes washers, showers, and bathtubs. The water used by the appliances contained chemical tracers with properties similar to those of potentially toxic chemicals found in many public water supplies. The experiments determined that significant percentages of all tested pollutants were transferred from water to indoor air.

Nearly all public water supplies contain at least small amounts of potentially toxic chemicals associated with the chlorination of drinking water, an otherwise beneficial process used to protect the public from pathogenic organisms. Furthermore, with many of these chemicals, exposure from breathing may rival or exceed exposure from drinking the water.

A much smaller number of Americans are exposed to significantly higher levels of harmful chemicals in well water that is tainted by gasoline (from leaking underground storage tanks) or industrial solvents (from spills on soil).

Dishwashers were observed to be particularly effective at transferring chemicals from water to indoor air. The bulk of the chemicals are released when the door is opened after dishwashing. Washing machines and dishwashers may increase exposure to chlorinated chemicals.

A large number of studies in the past six years have compared indoor and outdoor concentrations of hazardous pollutants. "In every study, with just about any pollutant, you find higher concentrations indoors than outdoors, even in the most polluted cities in the United States," said Corsi.

Trends during the latter half of the twentieth century have negatively affected indoor air quality. Attached garages can bring automobile exhaust and stored chemical vapors inside the house. Because of the energy crisis, homes and buildings have become more airtight, so pollutants build up indoors.

To adequately address the issue, several things must happen, according to Corsi:

* The public needs to become more educated about indoor air pollution.

* There should be more research into sources of hazardous air pollutants in homes, office buildings, and schools.

* Builders and consumers should use environmentally friendly (low-emitting) products.

* Residents and businesses should ventilate surroundings during water use. Another option is to use activated-carbon canisters that remove volatile organic compounds from water prior to discharge from a faucet or showerhead.

The report appeared in the July 1, 1999, issue of Environmental Science and Technology. The U.S. Environmental Protection Agency (U.S. EPA) is using the research to assess public exposures to chemicals once thought to enter the human body primarily through ingestion.