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 nvironmental engineers at 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, constituents of gasoline,
or by-products of drinking water chlorination (disinfection),
these chemicals can be transferred from water to indoor air.
This process, called volatilization or chemical stripping, adds
to a growing list of indoor air pollutants, the air researchers
reported in the July 1 issue of Environmental Science and
Technology.
 The
researchers, led by Dr. Richard Corsi, associate professor of
civil engineering, completed a series of experiments using household
appliances: dishwashers, clothes washers, showers, and bathtubs.
During each experiment, water used by the appliance contained
chemical tracers with properties similar to potentially toxic
chemicals found in many public water supplies. Corsi's group
determined that significant percentages of all tested pollutants
transferred from water to indoor air.
Corsi says
that 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, inhalation
(breathing) exposure to many of these chemicals may rival or
exceed exposure due to ingestion (drinking) of the water.
A much smaller
number of Americans is exposed to significantly higher levels
of harmful chemicals in well water tainted by gasoline from leaking
underground storage tanks, or industrial solvents previously
spilled on soil.
Dishwashers
were observed to be particularly effective at stripping chemicals
from water to indoor air, with the bulk of chemicals released
when the door is opened after a dish-washing event. Corsi also
notes that washing machines and dishwashers using chlorinated
bleaches or detergents may increase public exposure to chlorinated
chemicals through the formation and volatilization of these additional
chemicals.
The US Environmental
Protection Agency is currently using the research to assess public
exposures to chemicals, and subsequent health risks, once thought
to enter the human body primarily through ingestion.
A large number
of studies in the past six years have compared indoor/outdoor
concentrations of volatile and hazardous air pollutants. "In
every single study, with just about any pollutant, you find higher
concentrations indoors than outdoors -- even in the most polluted
cities in the United States," says Corsi.
Trends of
the latter half of this century have negatively impacted indoor
air quality. Attached garages can bring automobile exhaust and
stored chemical vapors inside the house. The energy crisis led
to more airtight homes and buildings, allowing pollutants to
build indoors.
Several things
must happen to appropriately address this issue, says Corsi.
- In general, the public knows more about outdoor
than indoor air pollution, and needs to become more educated
so they can help to solve their own problems.
- More research is needed to better understand
the many sources of hazardous air pollutants that occur in homes,
office buildings, and schools.
- Ultimately, sources of indoor air pollution
will likely be reduced through the sale of environmentally-friendly
(low emitting) building materials and consumer products, as well
as public education on ways to reduce exposure to toxic chemicals
in the home.
- In the case of volatilization from water,
it is important to maintain well-ventilated surroundings during
water use. For example, leave the bathroom fan on or window open
when showering, use the hood fan above the stove when boiling
water, etc. Commercially available activated carbon canisters
will remove volatile organic compounds from water prior to their
discharge through a faucet or shower head.
"There
are a lot of measures the public can take to reduce exposure
to such compounds. However, the first step is simply to make
sure the public understands the nature of the problem, and the
simple steps they can take to solve it," says Corsi. 
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