TY - JOUR
T1 - Mercury Emissions, Atmospheric Concentrations, and Wet Deposition across the Conterminous United States
T2 - Changes over 20 Years of Monitoring
AU - Olson, Connor I.
AU - Fakhraei, Habibollah
AU - Driscoll, Charles T.
N1 - Funding Information:
We thank Kathy F. Lambert, Colin Thackray, Justine Huetteman, and Jeremy Schreifels for critical review and feedback. We thank the National Science Foundation EMPOWER graduate training program for supporting the competition of this work. All data used in the present study are publicly available and free to access. Mercury deposition and precipitation data can be accessed from the Mercury Deposition Network ( http://nadp.slh.wisc.edu/mdn/ ). Air mercury fraction concentrations can be accessed from the Atmospheric Mercury Network ( http://nadp.slh.wisc.edu/AMNet/ ). Mercury emission data can be accessed from the U.S. EPA’s National Emission Inventory ( https://www.epa.gov/air-emissions-inventories/national-emissions-inventory-nei ). All shapefile data were accessed from the U.S. Census Bureau. All code used in this study will be made available upon reasonable request to the corresponding author (C.I.O.).
Publisher Copyright:
Copyright © 2020 American Chemical Society.
PY - 2020/6/9
Y1 - 2020/6/9
N2 - Mercury is a global pollutant whose supply to the environment has greatly increased due to human activities resulting in adverse effects on human and wildlife health. In response, the United States has substantially reduced mercury emissions over the last two decades, largely through air quality management; however, questions remain on the effectiveness of these emission controls in reducing mercury inputs to local ecosystems, due to a disproportional influence of global pools over local sources. Here, we show that trends in mercury concentrations in air and precipitation are largely decreasing across monitoring sites in the United States, coincident with decreases in stationary mercury emissions. Significant decreasing trends primarily occurred in the eastern United States, while trends in the western United States were more often insignificant or increasing, despite no clear increases in local, stationary emissions. For the eastern United States, local emissions appear to have had larger impacts on atmospheric and precipitation mercury concentrations than has been suggested from simulations using atmospheric models, suggesting that reductions in local mercury emissions can confer meaningful benefits to mercury-contaminated areas. These findings highlight the success of air management policies in the United States and are especially timely, as the United States Environmental Protection Agency has decided to roll back the Mercury and Air Toxics Standards.
AB - Mercury is a global pollutant whose supply to the environment has greatly increased due to human activities resulting in adverse effects on human and wildlife health. In response, the United States has substantially reduced mercury emissions over the last two decades, largely through air quality management; however, questions remain on the effectiveness of these emission controls in reducing mercury inputs to local ecosystems, due to a disproportional influence of global pools over local sources. Here, we show that trends in mercury concentrations in air and precipitation are largely decreasing across monitoring sites in the United States, coincident with decreases in stationary mercury emissions. Significant decreasing trends primarily occurred in the eastern United States, while trends in the western United States were more often insignificant or increasing, despite no clear increases in local, stationary emissions. For the eastern United States, local emissions appear to have had larger impacts on atmospheric and precipitation mercury concentrations than has been suggested from simulations using atmospheric models, suggesting that reductions in local mercury emissions can confer meaningful benefits to mercury-contaminated areas. These findings highlight the success of air management policies in the United States and are especially timely, as the United States Environmental Protection Agency has decided to roll back the Mercury and Air Toxics Standards.
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U2 - 10.1021/acs.estlett.0c00185
DO - 10.1021/acs.estlett.0c00185
M3 - Article
AN - SCOPUS:85088364394
SN - 2328-8930
VL - 7
SP - 376
EP - 381
JO - Environmental Science and Technology Letters
JF - Environmental Science and Technology Letters
IS - 6
ER -