Highlight
Trainees Expand Research on Pollution Removal Materials (PRMs)
UT-Austin IGERT trainee Erin Darling and affiliate Clement Cros conduct research at the Danish Technical University.
Achievement/Results
Three Environmental Engineering graduate students who are part of the National Science Foundation’s (NSF) Integrative Graduate Education and Research Traineeship (IGERT) program in Indoor Environmental Science and Engineering at The University of Texas at Austin (UT) are continuing a novel study of “pollution removal materials” (PRMs) to reduce human exposure to indoor pollutants without an energy penalty. This concept involves the use of architectural materials that can sequester or destroy harmful indoor pollutants without concomitant production of harmful reaction products or the energy penalty associated with most pollution control systems. This work is important for two reasons. First, human exposure to air pollution, even pollution of outdoor origin, is dominated by what is breathed indoors. Second, there is a move toward low to zero-energy buildings in the United States, and to achieve this goal will mean improved pollution control strategies that do not suffer from continuous energy penalties.
The PRM research was initiated by IGERT trainee Elliott Gall and affiliate alumnus Donna Kunkel, whose seminal work on the subject was published in the journal Building and Environment. Gall and Kunkel focused on ozone removal to unpainted gypsum board and to activated carbon mats that are hung from walls or used as sleeves over fan blades. During the past year trainee Gall continued his work by completing a Monte-Carlo simulation of PRM applications for homes in Houston, Texas, and showed that PRMs can be highly effective at removing ozone from indoor air and, thus, substantially reducing population exposures to ozone. Galls’s recent work has already been published in the journal Atmospheric Environment. He is continuing his work to better understand the role of material porosity on enhanced removal of ozone to PRMs. Gall and Kunkel previously mentored two undergraduate students who helped to complete an assessment of technology applications for PRMs. One of those students was Erin Darling, who is now a Ph.D. student and IGERT trainee.
Over the past year, trainee Darling and affiliate Clement Cros (Environmental Engineering) have studied clay-based wall plaster as a means for removing ozone from indoor air. The benefits of this product are that it is aesthetically pleasing (unlike previously tested PRMs) and can cover large surface areas. Darling completed experiments in the UTest House, a 3 bedroom/ 2 bath test house purchased with funding from the National Science Foundation’s IGERT program; the UTest House has become a major tool used by IGERT trainees and affiliates for their research. Her findings confirmed the value of clay-based wall plaster used on walls in a bedroom. The plaster is effective at removing ozone from indoor air and during experiments it also effectively lowered oxidized reaction products associated with ozone reaction with the normal painted gypsum wallboard in the test house.
Using discretionary funds made available from the University of Texas, trainee Darling and affiliate Cros were able to accompany program director and faculty participant Richard L. Corsi on a trip to Denmark in May of 2010. There, they worked with internationally-recognized experts on human perception analysis (from Poland and the Czech Republic) and world-class human subject chamber facilities at the Danish Technical University to study human perceptions of air contaminated with ozone, carpet or both, and untreated or treated with gypsum board coated with a clay-based plaster. Twenty-eight panelists were recruited for a multi-week study. The panelists were unaware of the sources or clay-based wall plaster in the chamber feed streams. Important findings were that polluted air treated by clay-based wall coverings had a statistically improved acceptability rating, and that gender played a major role in acceptability ratings; females were far more sensitive to conditions with pollution sources (higher unacceptability ratings) and clay-based wall coverings (higher acceptability scores). This latter finding was not one that the team was studying, but emerged from data analyses and is consistent with past studies that indicate that females are more sensitive to odors and pollution sources. The results of this study will be presented at podium by trainee Darling at Indoor Air 2011, a major international conference being organized and held in June 2011 by the IGERT program on Indoor Environmental Science and Engineering.
Address Goals
While past research has been completed on the removal of ozone to indoor materials, our studies are the first to systematically explore and document the potential for the strategic use of selective materials for lowering population exposures to ozone while reducing background levels of potentially harmful by-products that are formed when ozone reacts with common indoor surfaces. IGERT trainees and affiliates are now world leaders on this important topic. They are the first researchers to calculate the extent to which this strategy can reduce ozone exposures, and also the first to explore the importance of strategic placement of PRMs in areas that are already characterized by elevated indoor air speeds.
In the past year IGERT trainees and affiliates have extended their research to better understanding the most important processes that affect pollutant removal to PRMs in order to facilitate optimization of pollutant removal. For example, trainee Elliott Gall is the first to begin carrying out systematic studies of material porosity effects on diffusion of ozone into architectural materials. Trainee Erin Darling has shown the ability of clay plaster to remove ozone from indoor air and will soon extend her research to other pollutants. Darling and affiliate Clement Cros have also shown that air treated by clay-based wall plaster can also improve human perceptions of the indoor environment, an important finding in terms of the potential for improved satisfaction and productivity in buildings.
All of these findings and contributions relate to the goal of discovery. Furthermore, four past or present IGERT graduate students and an undergraduate student whom they have mentored have engaged in learning related to laboratory and field experimental methods, engineering analysis, surface chemistry, and fluid mechanics. All of these students have presented their results at major international conferences and have spoken to the public about their findings. In fact, because of trainee Erin Darling’s work, clay-based wall coverings have been adopted for use by the University of Texas (UT) Energy Institute and may also be adopted for expanded use through a major sustainability initiative for buildings on the UT campus; this reflects that others on the UT campus are learning from trainees in the IGERT program on Indoor Environmental Science and Engineering.
