Principal Investigator Noelle Selin
Work examines how persistent, toxic pollutants travel in the environment. Mercury and POPs are global environmental pollutants influenced by human activities. The dominant source of anthropogenic mercury emissions is burning of coal, but industrial processes such as metals production and intentional uses of mercury are also sources. POPs can be intentionally produced (for use as pesticides and industrial chemicals) or emitted as byproducts of combustion or other industrial processes. Both mercury and POPs accumulate in food webs, posing risks to human health and the environment.
Despite increasing attention to mercury and POPs as environmental problems, there are significant outstanding scientific questions regarding their behavior and chemistry in the atmosphere and biosphere. Constraining the cycling between the atmosphere and land and ocean reservoirs, and the extent to which the legacy of past anthropogenic activities affect current pollution, are critical needs. From a policy perspective, a key objective is to quantify the extent to which domestic and international emissions influence present-day deposition (and thus ultimately human exposure), so that emissions reduction activities can be implemented effectively. In addition, we are interested in constraining potential future changes in exposure due to climate change.
Using the GEOS-Chem global chemical transport model, we are examining the mercury cycle, using inverse modeling techniques to constrain sources, and informing efforts to measure and monitor atmospheric mercury. We participated in the 2013 Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks (NOMADSS) campaign, and are part of the modeling task force for the Global Mercury Observation System (GMOS). For POPs, we developed the first POPs model for GEOS-Chem, and used it to examine the fate and transport of PAHs to the Arctic and their gas-particle partitioning behavior. We are currently developing simulations for PCBs and PFOS/PFOA, as well as new uncertainty techniques for POPs simulations. We are also examining trans-Pacific transport of pollutants, and atmospheric response to policies on particulate matter and ozone.
Work in this area is funded by the U.S. National Science Foundation's CAREER program, the Arctic System Science Program, and the Atmospheric Chemistry Program. People involved in this work from the group include Carey Friedman, Shaojie Song, Colin Pike-Thackray, Mingwei Li, and Jareth Holt.