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Jaffe DA, Ninneman M, Nguyen L, Lee H, Hu L, Ketcherside D, Jin L, Cope E, Lyman S, Jones C, O'Neil T, Mansfield ML. Key results from the salt lake regional smoke, ozone, and aerosol study (SAMOZA). JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2024; 74:163-180. [PMID: 38198293 DOI: 10.1080/10962247.2024.2301956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 12/13/2023] [Indexed: 01/12/2024]
Abstract
The Northern Wasatch Front area is one of ~ 50 metropolitan regions in the U.S. that do not meet the 2015 O3 standard. To better understand the causes of high O3 days in this region we conducted the Salt Lake regional Smoke, Ozone and Aerosol Study (SAMOZA) in the summer of 2022. The primary goals of SAMOZA were: Measure a suite of VOCs, by Proton Transfer Reaction Mass Spectrometry (PTR-MS) and the 2,4-dinitrophenylhydrazine (DNPH) cartridge method.Evaluate whether the standard UV O3 measurements made in SLC show a positive bias during smoke events, as has been suggested in some recent studies.Use the observations to conduct photochemical modeling and statistical/machine learning analyses to understand photochemistry on both smoke-influenced and non-smoke days.Implications: The Northern Wasatch Front area is one of ~50 metropolitan regions in the U.S. that do not meet the 2015 O3 standard. To better understand the causes of high O3 days in this region we conducted the Salt Lake regional Smoke, Ozone and Aerosol Study (SAMOZA) in the summer of 2022. A number of policy relevant findings are identified in the manuscript including role of smoke and NOx vs VOC sensitivity.
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Affiliation(s)
- Daniel A Jaffe
- School of STEM, University of Washington Bothell, Bothell, WA, USA
- Department of Atmospheric Sciences, University of Washington Seattle, Seattle, WA, USA
| | - Matt Ninneman
- School of STEM, University of Washington Bothell, Bothell, WA, USA
| | - Linh Nguyen
- School of STEM, University of Washington Bothell, Bothell, WA, USA
| | - Haebum Lee
- School of STEM, University of Washington Bothell, Bothell, WA, USA
| | - Lu Hu
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, USA
| | - Damien Ketcherside
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, USA
| | - Lixu Jin
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, USA
| | - Emily Cope
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, USA
| | - Seth Lyman
- Bingham Research Center, Utah State University, Vernal, UT, USA
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, USA
| | - Colleen Jones
- Bingham Research Center, Utah State University, Vernal, UT, USA
| | - Trevor O'Neil
- Bingham Research Center, Utah State University, Vernal, UT, USA
| | - Marc L Mansfield
- Bingham Research Center, Utah State University, Vernal, UT, USA
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, USA
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Lyman SN, Elgiar T, Gustin MS, Dunham-Cheatham SM, David LM, Zhang L. Evidence against Rapid Mercury Oxidation in Photochemical Smog. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:11225-11235. [PMID: 35877386 DOI: 10.1021/acs.est.2c02224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Mercury pollution is primarily emitted to the atmosphere, and atmospheric transport and chemical processes determine its fate in the environment, but scientific understanding of atmospheric mercury chemistry is clouded in uncertainty. Mercury oxidation by atomic bromine in the Arctic and the upper atmosphere is well established, but less is understood about oxidation pathways in conditions of anthropogenic photochemical smog. Many have observed rapid increases in oxidized mercury under polluted conditions, but it has not been clearly demonstrated that these increases are the result of local mercury oxidation. We measured elemental and oxidized mercury in an area that experienced abundant photochemical activity (ozone >100 ppb) during winter inversion (i.e., cold air pools) conditions that restricted entrainment of air from the oxidized mercury-rich upper atmosphere. Under these conditions, oxidized mercury concentrations decreased day-upon-day, even as ozone and other pollutants increased dramatically. A box model that incorporated rapid kinetics for reactions of elemental mercury with ozone and OH radical overestimated observed oxidized mercury, while incorporation of slower, more widely accepted reaction rates did not. Our results show that rapid gas-phase mercury oxidation by ozone and OH in photochemical smog is unlikely.
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Affiliation(s)
- Seth N Lyman
- Bingham Research Center, Utah State University, Vernal, Utah 84078, United States
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, United States
| | - Tyler Elgiar
- Bingham Research Center, Utah State University, Vernal, Utah 84078, United States
| | - Mae Sexauer Gustin
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, Reno, Nevada 89557, United States
| | - Sarrah M Dunham-Cheatham
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, Reno, Nevada 89557, United States
| | - Liji M David
- Bingham Research Center, Utah State University, Vernal, Utah 84078, United States
| | - Lei Zhang
- School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, China
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