@article{19c7193657ee4370889032f4408a7122,
title = "Nitrogen dry deposition to Lake Superior and Lake Michigan",
abstract = " Nitrate (NO 3 − ) levels in Lake Superior have increased from historic levels of about 5 μM to its current concentration of about 25 μM. The atmosphere makes a substantial contribution to the nitrogen budgets for Lake Superior and Lake Michigan. This study provides a more well-defined estimate of nitrogen dry deposition rates derived from the measurement of over-water concentrations, and in situ meteorological measurements, which were input into the Resistance Model. We obtained a nitrogen dry deposition rate of [(3.41 ± 2.26) × 10 7 kg N/yr; (5.90 ± 3.91) kg N/ha/yr] over Lake Michigan, and [(1.54 ± 1.06) × 10 7 kg N/yr; (1.87 ± 1.27) kg N/ha/yr] over Lake Superior. Nitric acid (HNO 3 ), which originates from the combustion of fossil fuels, contributes 84% of the total nitrogen dry deposition to Lake Michigan; and 66% to Lake Superior. Ammonia (NH 3 ), which originates from agricultural activities and gasoline combustion, is the second highest contributor of nitrogen dry deposition to both lakes: contributing 13% to Lake Michigan and 32% to Lake Superior. The nitrogen dry deposition is approximately 68% of the nitrogen wet deposition over Lake Superior, and approximately 80% of wet deposition over Lake Michigan. The over-water dry deposition velocity of HNO 3 and NH 3 were also evaluated. We obtained morning deposition velocities of 0.099 cm/s for NH 3 and 0.095 cm/s for HNO 3 ; and afternoon values of 0.137 cm/s for NH 3 and 0.132 cm/s for HNO 3 . Another key finding is that the atmospheric concentrations of nitrogen compounds near Lake Michigan and Lake Superior have decreased since 2003. ",
keywords = "Air quality, Deposition velocity, Lake Michigan, Lake Superior, Nitrogen dry deposition, Resistance model",
author = "Foley, {Theresa A.} and Betterton, {Eric A.}",
note = "Funding Information: This research was not funded by any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Publication costs were supported in part by the Agnese Nelms Haury Program at the University of Arizona. The authors would like to thank all of the dedicated pilots, technicians and meteorologists from the states of Wisconsin, Illinois, Indiana, and Michigan. The authors would like to thank Dr. James Schauer of the University of Wisconsin and Tim Trap of the Wisconsin Department of Natural Resources for their work building the PM2.5, mercury and HNO3 samplers. We also thank Ed Miller, Larry Bruss, Mark Allen, Bill Adamski and Mary Mertes of the Wisconsin Department of Natural Resources who helped to make this study possible. The following researchers made many helpful comments and suggestions that have strengthened this paper: Dr. Andrew Comrie and Dr. Christopher Castro of the University of Arizona; Dr. James Schauer of the University of Wisconsin; and Dr. Charles Stanier of the University of Iowa. We are also grateful to an anonymous reviewer. Funding Information: This research was not funded by any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Publication costs were supported in part by the Agnese Nelms Haury Program at the University of Arizona. The authors would like to thank all of the dedicated pilots, technicians and meteorologists from the states of Wisconsin, Illinois, Indiana, and Michigan. The authors would like to thank Dr. James Schauer of the University of Wisconsin and Tim Trap of the Wisconsin Department of Natural Resources for their work building the PM 2.5 , mercury and HNO 3 samplers. We also thank Ed Miller, Larry Bruss, Mark Allen, Bill Adamski and Mary Mertes of the Wisconsin Department of Natural Resources who helped to make this study possible. The following researchers made many helpful comments and suggestions that have strengthened this paper: Dr. Andrew Comrie and Dr. Christopher Castro of the University of Arizona; Dr. James Schauer of the University of Wisconsin; and Dr. Charles Stanier of the University of Iowa. We are also grateful to an anonymous reviewer. Publisher Copyright: {\textcopyright} 2018",
year = "2019",
month = apr,
doi = "10.1016/j.jglr.2018.12.003",
language = "English (US)",
volume = "45",
pages = "224--239",
journal = "Journal of Great Lakes Research",
issn = "0380-1330",
publisher = "International Association of Great Lakes Research",
number = "2",
}