Al Hodgson and Richard Allen test methyl chloride exposures using the environmental chamber.

On the second floor of an unremarkable building at LBL, researchers are using a room within a room to smoke out indoor air pollutants. The environmental chamber is a stainless-steel-lined room of 540 ft cubed (20 meters cubed) which can be operated in several ways to meet the needs of different research projects, including studies for which a very low background is required. Scientists of the Indoor Environment Program and their collaborators use the chamber as a controlled indoor environment to study the behavior of a variety of indoor pollutants ranging from cigarette smoke to volatile organic compounds (VOCs) from new carpets.

At the moment, four projects use the facility. Principal investigator Al Hodgson, a chemist with overall responsibility for the chamber and its operation, is the leader of a team studying the emissions of volatile organic compounds from carpets and carpet pads with funding from the Consumer Products Safety Commission (CPSC). A new carpet or carpet backing material outgasses VOCs at rates that decrease with time and that can be measured accurately in the environmental chamber. Carpeting has been reported to be linked with sensory irritation and other health or comfort problems. The CPSC has been requested by some state agencies to label carpet materials as hazardous.

Joan Daisey and colleagues are studying the emissions of nitrosamines from cigarette smoke and how their concentrations change with time indoors. Nitrosamines, which have been implicated as carcinogens in some studies, are found in many smoked foods and drinks, including bacon and Scotch. Funded by the California Air Resources Board, this research may eventually lead to a better understanding of the relationship between human exposure to environmental tobacco smoke and related health risks, as well as better standards of acceptable exposure. Investigators will use their chamber test results as input to a computer model of human exposure to nitrosamines from cigarette smoke.

Developing a tracer technique to characterize the ventilation rates in office buildings is the object of a study headed by William Fisk and funded by DOEs Office of Building Technologies. A small source of a fluorocarbon-based tracer placed throughout an office building can characterize the emissions of pollutants from common indoor sources like carpets. The environmental chamber offers a convenient tool for testing the tracer's accuracy and measurability.

Finally, in collaboration with Richard White of the University of California's Department of Electrical Engineering and Computer Science, Indoor Environment Program researchers are testing new sensor technology for measuring the indoor concentrations of organic compounds such as toluene and formaldehyde.

Users of the environmental chamber can work with larger assemblages of materials representative of those in homes and offices and scale the samples to test factors like surface-to-volume ratios as experimental parameters, a capability smaller chambers don't have. A growing awareness of the possible risks to human health of indoor emissions sources should keep the environmental chamber a popular instrument for understanding exposure risks for some time to come.

--Allan Chen

Al Hodgson
Indoor Air Chemistry Group
Indoor Environment Program
(510) 486-5301; (510) 486-6658 fax