This grant supports efforts by Vicki Grassian, Distinguished Professor of Physical Chemistry at the University of California, San Diego, to monitor the chemistry that occurs on indoor surfaces. Grassian and her team will compare surface adsorption and surface reactions (kinetics, extent of reaction) over a range of different types of material surfaces found in homes, offices, and public spaces, including glass (windows), titanium dioxide (paints and self-cleaning surfaces), concrete, and drywall. She will conduct these experiments on model systems to better understand the chemistry of these materials, as well as on surfaces coated with thin films to determine if they behave differently. Gases of interest include ozone, nicotine, cyclomethylsiloxanes (components of personal care products), ammonia, and co-mixtures of these. In addition, Grassian will conduct a series of controlled experiments that vary the relative humidity, temperature, and light surfaces are exposed to, and measure how chemical reaction mechanisms and reaction kinetics vary across cases. An important aspect of this research is to understand how these factors drive the chemistry of indoor surfaces with gases present in indoor environments. They plan to probe the molecular processes that occur on these indoor surfaces using molecular-based probes such as X-ray photoelectron spectroscopy, vibrational spectroscopy, and scanning probe techniques such as atomic force microscopy. This project will characterize many of the physical and chemical transformations taking place on indoor surfaces and generate new data for indoor chemistry models. This proposal will provide a molecular-level understanding of chemistry on indoor surfaces as affected by important factors such as organic coatings, light, and relative humidity. The results will be shared through peer-reviewed publications and presentations at conferences and meetings. At least two students and one postdoc will be trained.

Funds from this grant support work by atmospheric chemist Paul Ziemann to expand our understanding of chemical sources, sinks, and transformations of indoor environments, and to develop physical-chemical mechanisms to describe these processes. Ziemann will conduct a series of pilot studies to examine a range of indoor environments. His studies will aim to (1) identify similarities and differences in the organic chemical composition of indoor gases, particles, and surfaces; (2) determine organic chemical contributions from various sources; (3) determine the effects of organic gases, oxidants, acids, humidity, light, and temperature on gas, particle, and surface composition; (4) determine potential effects of organic compounds emitted by humans, either directly or as a result of reactions; and (5) develop physical-chemical mechanisms to explain observed compositions and processes. The range of indoor environments to be tested includes an art museum, classrooms, offices, a student athletic center, student dining facilities, and local residences. This project will provide new insights into the physical and chemical processes that determine the composition of indoor air and allow for development of a deeper understanding of how different indoor environments function. The results also promise to be valuable for developing models for predicting the chemical composition of indoor air and strategies for improving indoor air quality. The results will be shared through peer-reviewed publications and presentations at conferences and meetings. At least two students and one postdoctoral fellow will be trained.

This grant funds research by Professor William Nazaroff, an expert on the physics and chemistry of indoor air pollutants, and Professor Allen Goldstein, an expert on anthropogenic and natural contributions to the chemical composition of the atmosphere. The researchers are working to expand the understanding of processes controlling abundance, sources, and fates of organic chemicals indoors, focusing on the roles of human occupants as agents influencing indoor air chemistry. Over a several-week period, the researchers will monitor the indoor air of a residence under five conditions: (a) house vacant, emphasis on spatial resolution; (b) house vacant, emphasis on temporal resolution; (c) house normally occupied, emphasis on spatial resolution; (d) house normally occupied, emphasis on temporal resolution; and (e) manipulation experiments, such as cooking, cleaning, or dishwashing. Monitoring will focus on detecting several important chemicals, including volatile organic compounds (VOCs), nitrate radicals, nitrogen oxide trace gases, carbon dioxide, and ozone. In addition, the team will sample environmental conditions such as temperature, relative humidity, ultrafine particulate concentration, and air exchange rates. Samples will then be analyzed to try to apportion VOC chemical concentrations in sampled indoor air to their sources, including outdoor air, building-associated sources present when the residence is vacant, occupant-associated sources, and secondary production from indoor chemical reactions. This project will generate important new insights into indoor chemistry, which will be shared through peer-reviewed publications and presentations at conferences and meetings. At least three students will be trained during the course of the project.

This grant funds a three-year collaboration between Jonathan Abbatt, professor of chemistry, and Jeffrey Siegel, associate professor of civil and mineral engineering, to expand our understanding of multiphase chemistry in indoor environments. The overall goal of their grant-supported work is to better understand the nature of the reactive processes that affect the composition of material deposited on indoor surfaces and to examine the associated impacts on the state of the indoor environment. Abbatt and Siegel have chosen three common sources of materials that deposit on surfaces indoors: skin oil materials from people; particles generated by combustion processes such as cooking or cigarette smoking; and common chlorine- and nitrogen-containing cleaning agents such as household bleach. They will expose these chemicals to indoor air under both laboratory and real-world conditions and observe how such exposure leads to particulate deposits and the creation of new compounds. Abbatt and his team will use a comprehensive range of state-of-the-art mass spectrometer instrumentation to conduct the chemical analyses. Most of these instruments have been rarely, if ever, used indoors and the team expects to develop new analytical methods for their deployment indoors. The team will share their findings through peer-reviewed publications and presentations at conferences and meetings. At least one postdoctoral fellow and three students will be trained during the project.

Recent advances in instrumentation have transformed our ability to study chemical reactions and analyze the composition of chemicals in the air. These advances provide an excellent opportunity to expand our understanding of the chemistry of indoor environments. This grant funds a preliminary study by Barbara J. Turpin, a professor in the Department of Environmental Sciences and Engineering at the University of North Carolina, Chapel Hill, of the impact of moisture on indoor chemistry. Turpin and her team plan to take samples from the air of 10 to 20 occupied homes, treat the samples with indoor oxidants (reactants) such as OH or NO3 radicals, and then monitor the reaction products using a variety of techniques. The study builds on Turpin’s prior work demonstrating that aqueous organic chemistry alters the composition and effects of air pollution outdoors. Turpin expects to produce at least two peer-reviewed articles based on the study, and she and her team will present their findings at national and international meetings. In addition, Turpin will prepare a short report that outlines important research questions and obstacles to be overcome for indoor air chemistry.