Influenza is responsible for an estimated 36,000 deaths, 3.1 million hospitalization days, and 31 million outpatient visits per year in the US. While the structure, genetics, infectivity, and pathogenicity of influenza viruses are well understood, much less is known about transmission and the dynamics of the virus in the environment. By employing an interdisciplinary approach based on environmental engineering and aerosol science, we have shown that airborne transmission of influenza is likely and that environmental conditions affect the transmissibility of the virus. Recent studies suggest that humidity modulates influenza virus survival, transmission, and seasonality, but the mechanism underlying this relationship is not known. We hypothesize that humidity-controlled changes in the chemistry of respiratory droplets affecting virus viability. Influenza viruses are released from infected hosts in respiratory droplets that undergo partial or complete evaporation in the environment. Resulting changes in their chemical composition, such as altered pH, increased salt and protein concentrations, crystallization, or phase separation, could lead to inactivation of the virus. Overall, results of this research have the potential to promote improvements in the forecasting of disease dynamics, development of infection control strategies, and prediction of the pandemic potential of emerging virus strains.
Linsey Marr is the Charles P. Lunsford Professor of Civil and Environmental Engineering at Virginia Tech. Her research group applies an interdisciplinary approach to study pollutants in indoor and outdoor air. She is especially interested in emerging or non-traditional aerosols such as engineered nanomaterials and viral pathogens and how they can be physically and chemically transformed in the environment. She is a Fellow of the International Society of Indoor Air Quality and Climate and an Associate Editor of Microbiome. She was recently appointed to the National Academies’ Board on Environmental Studies and Toxicology. Marr received a B.S. in Engineering Science from Harvard College and a Ph.D. in Civil and Environmental Engineering from the University of California at Berkeley and completed her post-doctoral training in Earth, Atmospheric, and Planetary Sciences at the Massachusetts Institute of Technology.
The legacy of lead-containing materials used for water supply poses challenges to tap water quality. In contrast to drinking water contaminants that have their origins in the source water and can be removed at a treatment plant, the source of lead in drinking water is the pipe that connects a home to the water main and the plumbing within the home. Concentrations of lead in tap water are governed by the chemical reactions between the water in the pipe and the scale of solid phases that develops on the inner surface of the pipe. Perturbations of the water chemistry have resulted in high profile crises of lead in drinking water (e.g., Washington, DC and Flint, Michigan). However, adjustment of the water chemistry is also a lever that can be used to minimize lead release to drinking water.
Bench-scale and pilot-scale experiments have explored the influence of water chemistry on lead in drinking water. The effectiveness of orthophosphate as a corrosion inhibitor and its impact on the composition and structure of pipe scales were evaluated in a series of bench-scale experiments with lead pipes. The formation and stability of lead(IV) oxide (PbO2), a low solubility solid that is only stable in the presence of free chlorine, is an example of the importance of oxidation-reduction reactions. Redox reactions are also relevant to the galvanic corrosion that can occur during partial lead service line replacements.
Professor Giammar is the Walter E. Browne Professor of Environmental Engineering in the Department of Energy, Environmental and Chemical Engineering at Washington University in St. Louis. Professor Giammar's research focuses on chemical reactions that affect the fate and transport of heavy metals, radionuclides, and other inorganic constituents in natural and engineered aquatic systems. His recent work has investigated the removal of arsenic and chromium from drinking water, control of the corrosion of lead pipes, geologic carbon sequestration, and biogeochemical processes for remediation of uranium-contaminated sites. His research has been sponsored by the National Science Foundation, Department of Energy, and Water Research Foundation. Professor Giammar is currently an Associate Editor of Environmental Science & Technology. Professor Giammar completed his B.S. at Carnegie Mellon University, M.S. and Ph.D. at Caltech, and postdoctoral training at Princeton University before joining Washington University in St. Louis in 2002. He is a registered professional engineer in the State of Missouri.