Not only did Ferro design the study, but she also performed the activities. What kind of dance did she do? "Probably best described as solo salsa," she says. "Luckily, I did not take any videotape."

Vacuuming was also a large source of particles. Vacuum brushes release deeply embedded particles from the carpet; the motor produces additional particles; and the bags are not 100 percent efficient in collecting particles, Ferro says. Only one type of vacuum was tested; different cleaners could produce different results, depending on the design.

"The result that was most surprising to me was that just walking around can resuspend almost as much dust as vacuuming," Ferro says.

The majority of the particles were larger than five micrometers in diameter, but smaller particles still played a significant role. "Smaller particles tend to deposit deeper in the lungs than the larger particles, potentially causing more harm," Ferro says. The U.S. Environmental Protection Agency classifies these as "fine particles," which have been associated with increased respiratory disease, decreased lung functioning and even premature death.

The results could help people make a variety of decisions about living in their homes. "One study estimates that about two-thirds of house dust is tracked in from outdoors," Ferro says. "Therefore, leaving shoes at the door can make a big difference in reducing the particle reservoir on the floor." She also recommends leaving windows open while cleaning to increase ventilation; limiting the use of toxic household products, like pesticides; and installing non-carpet flooring.

Ferro has since performed another study in a different home, with similar results. "My focus now is to determine the actual mechanisms for resuspension from human activity and perform the work in an indoor ai
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Contact: Michael Bernstein
m_bernstein@acs.org
202-872-6042
American Chemical Society
9-Mar-2004