He was a volunteer in an HSPH study conducted by colleagues in the Department of Environmental Health and by doctoral students in the Exposure, Epidemiology, and Risk Program. After receiving approval from the School’s Human Subjects Committee, Levy embarked as a participant in the study, designed to assess personal exposure to specific chemicals in the air.

For two days last May, he wore the backpack, given to him by the study’s creators, which contained lightweight monitoring equipment to trap air molecules. If not for the two yellow tubes protruding from the bag and the sound generated by a pump, the backpack would have looked perfectly normal.

"I was surprised that more people didn’t ask me about it," said Levy. "Overall, it was a positive experience because sometimes it is instructive for a researcher to be on the other side of the fence as a study subject."

	Doctoral student Miranda Loh models the backpack, which she helped design.

BEAM is visionary in that it focuses on the chemical exposures of individuals, who spend time indoors and outdoors and can come into contact with the same compound different ways.

Explained Deborah Bennett, principal investigator of BEAM, "Nobody lives in just one setting. We are looking at different surroundings that we call microenvironments and trying to piece together personal exposures."

Bennett is assistant professor of environmental health and risk assessment in the Departments of Environmental Health and Health Policy and Management.

Air sampling machines were set up outside of the homes of study subjects.

To tease out information on exposures from outdoor air pollution sources, the researchers set up sampling equipment outside of the homes of study subjects and established three fixed sites in the Boston area.

This winter, the study’s participants will be asked to repeat the experiment, giving the researchers data from two seasons because changes in weather, climate, and temperatures affect how air pollution disperses. Also, people are less likely to have windows opened during the winter, which influences exposure to airborne particles.

Many people are at least generally aware of major outdoor pollutants, such as car exhaust fumes, and their common sources. But, some people may assume their exposure to indoor pollutants is pretty limited. BEAM researchers know there are a number of common household substances that, even when stable, emit gases as unhealthy compounds. They are focusing on a few of these chemicals for the study:

• Formaldehyde, from some building materials such as particle board; cleansers and deodorizers; glues and resins, such as those used in some carpet backings

• 1,4-dichlorobenzene, from mothballs and some deodorizers

• Chloroform, from chlorinated tap water

• Toluene, from numerous consumer products, solvents, and building supplies

Some of these compounds are considered probable human carcinogens by the Environmental Protection Agency, but the bigger question is how much exposure is needed to make humans seriously ill. BEAM does not attempt to associate exposure with the development of specific diseases. Instead, Bennett hopes the research will help scientists make more accurate assessments of personal exposures and open a door to larger studies of personal exposures to chemicals.