As scientists learn more about the potentially harmful effects of indoor air pollution, nations around the world are imposing increasingly strict regulations on chemical emissions from furnishings, paints, and building materials.
Using a new room-sized environmental test chamber, more than a dozen smaller chambers, and a mass spectrometric center able to measure ultra-trace concentrations of airborne chemicals being emitted from products, scientists at the Georgia Tech Research Institute (GTRI), Atlanta, are helping manufacturers meet those international standards to minimize emissions.
“We can help manufacturers address regulatory issues,” said Charlene Bayer, principal research scientist at GTRI’s Health and Environmental Systems Laboratory. “Because U.S. manufacturers sell their products worldwide, they must meet emission regulations imposed by nations in Europe and Asia. We make the measurements companies need to improve their products.”
For example, the testing helps manufacturers of indoor furnishings select components that have lower emissions. It also helps textile and apparel companies choose fabric finishes that both survive cleaning and minimize emissions. And, it helps makers of paints and other wallcoverings select biocides and other chemical constituents with the least impact on the indoor environment.
Large enough to accommodate humans or animals, the new 27.5-cubic-meter environmental chamber will also allow researchers to study broader concerns - including the impact of low-level indoor air pollutants on productivity and human health.
“There is an emphasis now on developing high-performance schools, and part of that will be to measure how changes in indoor air quality improve the performance of children,” explained Bayer. “By studying how emissions from normal furnishings affect children performing classroom tasks, you can estimate what might happen if you reduce the emissions.”
Tests involving humans will be carefully designed to avoid exposing subjects to potentially harmful levels. The research will also be done under close medical supervision, with cameras and a special windowed door to monitor subjects inside the chamber.
Beyond helping manufacturers improve their products, the new facility may lead to a better understanding of which compounds cause problems and how indoor pollutants form. There is evidence, Bayer said, that the chemistry inside buildings is more complex than previously thought.
It’s known, for instance, that ozone produced outdoors during summer months enters buildings in significant amounts. There, the powerful oxidant may react with volatile organic compounds emitted from indoor furnishings to create a chemical soup that includes compounds not originally present in the furnishings.
“The chances are very good that it’s not the emissions we know about that are really bothering people, but rather the compounds that result when the emitted chemicals react with ozone,” Bayer said. “That could be quite significant in urban areas like Atlanta that have high levels of ground-level ozone.”
The large chamber can simulate real-world environmental conditions inside buildings. Coupled with the sensitive mass spectrometers, that allows those low-level chemical reactions to be studied in detail.
“We really have to look at the interactions between chemicals and the changing indoor air chemistry,” Bayer added. “That’s something we can now do because we have the room-sized chamber.”
Beyond an improved understanding of indoor air quality, GTRI’s environmental chambers can also be used to calibrate a broad range of new sensors being developed.
“We can put sensors into a well-controlled environment that simulates real conditions,” Bayer said. “We can expose the sensors to carefully-controlled levels of individual compounds, as well as to combinations of compounds.”
Also under development is a vest-based instrument for measuring the airborne emissions that can affect children with asthma. By correlating exposures with attacks, the vest will help researchers better understand the factors that lead to asthma problems.
In all, GTRI operates 15 environmental chambers that range in size from just 135 milliliters up to 27.5 cubic meters.
Samples taken from the chambers are analyzed by four mass spectrometers designed for different types of identification. For example, one instrument is used to analyze light gases such as carbon dioxide, which is produced by the respiration of living organisms such as bacterial and fungi. Another system is designed for proteomic and other biomedical research. The instruments can measure as low as femtogram quantities of chemical compounds.
The facility also includes other instruments, including gas chromatograph/mass spectrometer combinations. For testing the efficiency of air-filtration systems, Bayer uses a smoking machine that helps simulate a smoke-filled environment. The test facility also analyzes the efficiency of other equipment designed to clean the air.
Beyond the expertise and facilities in GTRI’s own labs, Bayer can call on researchers in Georgia Tech’s academic colleges - as well as collaborators at Emory University, Georgia State University, and the University of Miami Medical School.
“Combining these capabilities, we can focus on the far-reaching and difficult issues,” she said. “The linkage to academic researchers and to these other schools gives us tremendous abilities to study complex issues.”