1
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Shutter J, Cox J, Keutsch FN. Leaf-Level Bidirectional Exchange of Formaldehyde on Deciduous and Evergreen Tree Saplings. ACS EARTH & SPACE CHEMISTRY 2024; 8:723-733. [PMID: 38654895 PMCID: PMC11033940 DOI: 10.1021/acsearthspacechem.3c00325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 01/19/2024] [Accepted: 01/26/2024] [Indexed: 04/26/2024]
Abstract
Gas-phase formaldehyde (HCHO) is formed in high yield from the oxidation of many volatile organic compounds (VOCs) and is commonly used as a constraint when testing the performance of VOC oxidation mechanisms in models. However, prior to using HCHO as a model constraint for VOC oxidation in forested regions, it is essential to have a thorough understanding of its foliar exchange. Therefore, a controlled laboratory setup was designed to measure the emission and dry deposition of HCHO at the leaf-level to red oak (Quercus rubra) and Leyland cypress (Cupressus × leylandii) tree saplings. The results show that HCHO has a compensation point (CP) that rises exponentially with temperature (22-35 °C) with a mean range of 0.3-0.9 ppbv. The HCHO CP results are also found to be independent of the studied tree species and 40-70% relative humidity. Given that HCHO mixing ratios in forests during the daytime are usually greater than 1 ppbv, the magnitude of the CP suggests that trees generally act as a net sink of HCHO. Additionally, the results show that HCHO foliar exchange is stomatally controlled and better matches a reactivity factor (f0) of 0 as opposed to 1 in conventional dry deposition parametrizations. At 30 °C, daytime HCHO dry deposition fluxes are reduced by upward of 50% when using f0 = 0 and a nonzero HCHO CP, although deposition remains the dominant canopy sink of HCHO. A reduced deposition sink also implies the increased importance of the gas-phase photolysis of HCHO as a source of HO2.
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Affiliation(s)
- Joshua
D. Shutter
- Department
of Chemistry and Chemical Biology, Harvard
University, Cambridge, Massachusetts 02138, United States
| | - Joshua
L. Cox
- Department
of Chemistry and Chemical Biology, Harvard
University, Cambridge, Massachusetts 02138, United States
| | - Frank N. Keutsch
- Department
of Chemistry and Chemical Biology, Harvard
University, Cambridge, Massachusetts 02138, United States
- Harvard
John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Department
of Earth and Planetary Sciences, Harvard
University, Cambridge, Massachusetts 02138, United States
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2
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Zhao X, Meng J, Li Q, Su G, Zhang Q, Shi B, Dai L, Yu Y. Source apportionment and suitability evaluation of seasonal VOCs contaminants in the soil around a typical refining-chemical integration park in China. J Environ Sci (China) 2024; 137:651-663. [PMID: 37980048 DOI: 10.1016/j.jes.2023.02.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 02/20/2023] [Accepted: 02/21/2023] [Indexed: 11/20/2023]
Abstract
Accurate source apportionment of volatile organic compounds (VOCs) in soil nearby petrochemical industries prevailing globally, is critical for preventing pollution. However, in the process, seasonal effect on contamination pathways and accumulation of soil VOCs is often neglected. Herein, Yanshan Refining-Chemical Integration Park, including a carpet, refining, synthetic rubber, and two synthetic resin zones, was selected for traceability. Season variations resulted in a gradual decrease of 31 VOCs in soil from winter to summer. A method of dry deposition resistance model coupling partitioning coefficient model was created, revealing that dry deposition by gas phase was the primary pathway for VOCs to enter soil in winter and spring, with 100 times higher flux than by particle phase. Source profiles for five zones were built by gas sampling with distinct substance indicators screened, which were used for positive matrix factorization factors determination. Contributions of the five zones were 14.9%, 20.8%, 13.6%, 22.1%, and 28.6% in winter and 33.4%, 12.5%, 10.7%, 24.9%, and 18.5% in spring, respectively. The variation in the soil sorption capacity of VOCs causes inter-seasonal differences in contribution. The better correlation between dry deposition capacity and soil storage of VOCs made root mean square and mean absolute errors decrease averagely by 8.8% and 5.5% in winter compared to spring. This study provides new perspectives and methods for the source apportionment of soil VOCs contamination in industrial sites.
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Affiliation(s)
- Xu Zhao
- Key Laboratory of Environmental Nanotechnology and Health Effects, State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Meng
- Key Laboratory of Environmental Nanotechnology and Health Effects, State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qianqian Li
- Key Laboratory of Environmental Nanotechnology and Health Effects, State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guijin Su
- Key Laboratory of Environmental Nanotechnology and Health Effects, State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Qifan Zhang
- Key Laboratory of Environmental Nanotechnology and Health Effects, State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bin Shi
- Key Laboratory of Environmental Nanotechnology and Health Effects, State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lingwen Dai
- Key Laboratory of Environmental Nanotechnology and Health Effects, State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yong Yu
- State Environmental Protection Key Laboratory of Quality Control in Environmental Monitoring, China National Environmental Monitoring Center, Beijing 100012, China.
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3
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Selimovic V, Ketcherside D, Chaliyakunnel S, Wielgasz C, Permar W, Angot H, Millet DB, Fried A, Helmig D, Hu L. Atmospheric biogenic volatile organic compounds in the Alaskan Arctic tundra: constraints from measurements at Toolik Field Station. ATMOSPHERIC CHEMISTRY AND PHYSICS 2022; 22:14037-14058. [PMID: 37476609 PMCID: PMC10358744 DOI: 10.5194/acp-22-14037-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
The Arctic is a climatically sensitive region that has experienced warming at almost 3 times the global average rate in recent decades, leading to an increase in Arctic greenness and a greater abundance of plants that emit biogenic volatile organic compounds (BVOCs). These changes in atmospheric emissions are expected to significantly modify the overall oxidative chemistry of the region and lead to changes in VOC composition and abundance, with implications for atmospheric processes. Nonetheless, observations needed to constrain our current understanding of these issues in this critical environment are sparse. This work presents novel atmospheric in situ proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) measurements of VOCs at Toolik Field Station (TFS; 68°38' N, 149°36' W), in the Alaskan Arctic tundra during May-June 2019. We employ a custom nested grid version of the GEOS-Chem chemical transport model (CTM), driven with MEGANv2.1 (Model of Emissions of Gases and Aerosols from Nature version 2.1) biogenic emissions for Alaska at 0.25° × 0.3125° resolution, to interpret the observations in terms of their constraints on BVOC emissions, total reactive organic carbon (ROC) composition, and calculated OH reactivity (OHr) in this environment. We find total ambient mole fraction of 78 identified VOCs to be 6.3 ± 0.4 ppbv (10.8 ± 0.5 ppbC), with overwhelming (> 80 %) contributions are from short-chain oxygenated VOCs (OVOCs) including methanol, acetone and formaldehyde. Isoprene was the most abundant terpene identified. GEOS-Chem captures the observed isoprene (and its oxidation products), acetone and acetaldehyde abundances within the combined model and observation uncertainties (±25 %), but underestimates other OVOCs including methanol, formaldehyde, formic acid and acetic acid by a factor of 3 to 12. The negative model bias for methanol is attributed to underestimated biogenic methanol emissions for the Alaskan tundra in MEGANv2.1. Observed formaldehyde mole fractions increase exponentially with air temperature, likely reflecting its biogenic precursors and pointing to a systematic model underprediction of its secondary production. The median campaign-calculated OHr from VOCs measured at TFS was 0.7 s-1, roughly 5 % of the values typically reported in lower-latitude forested ecosystems. Ten species account for over 80 % of the calculated VOC OHr, with formaldehyde, isoprene and acetaldehyde together accounting for nearly half of the total. Simulated OHr based on median-modeled VOCs included in GEOS-Chem averages 0.5 s-1 and is dominated by isoprene (30 %) and monoterpenes (17 %). The data presented here serve as a critical evaluation of our knowledge of BVOCs and ROC budgets in high-latitude environments and represent a foundation for investigating and interpreting future warming-driven changes in VOC emissions in the Alaskan Arctic tundra.
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Affiliation(s)
- Vanessa Selimovic
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, USA
| | - Damien Ketcherside
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, USA
| | | | - Catherine Wielgasz
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, USA
| | - Wade Permar
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, USA
| | - Hélène Angot
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO, USA
| | - Dylan B. Millet
- Department of Soil, Water, and Climate, University of Minnesota Twin Cities, St Paul, MN, USA
| | - Alan Fried
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO, USA
| | | | - Lu Hu
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, USA
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4
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Dai L, Meng J, Zhao X, Li Q, Shi B, Wu M, Zhang Q, Su G, Hu J, Shu X. High-spatial-resolution VOCs emission from the petrochemical industries and its differential regional effect on soil in typical economic zones of China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 827:154318. [PMID: 35257751 DOI: 10.1016/j.scitotenv.2022.154318] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/27/2022] [Accepted: 03/01/2022] [Indexed: 06/14/2023]
Abstract
Volatile organic compounds (VOCs) are toxic to the ecological environment. The emission of VOCs into the atmosphere has already caused attention. However, few studies focus on their regional effects on soil. As a major VOCs source in China, research on the effect of petrochemical industry on the environment is urgent and essential for regional control and industrial layout. This study established national VOCs emission inventory of five petrochemical sub-industries and spatial distribution based on consumption of raw material or products' yield and 28,888 factories. The VOCs emissions showed continuously increasing trend from 2008 to 2019, with cumulative 1.83 × 107 t, wherein these from rapid economic development zones accounted for 66.10%. The detected concentrations of VOCs in various industries combined with meteorological parameters were used in Resistance Model to quantify regional dry deposition. Higher concentrations of 111 VOC species were 238.27, 260.01, 207.54 μg·m-3 from large-scale enterprises for crude oil and natural gas extraction, oil processing, synthetic rubber and resin, leading to higher deposition ratios of 0.81%-0.94%, 0.70%-0.81%, 1.50%-1.75% in rapid economic development zones, respectively. The regional climate condition played a dominant role. Annual VOCs dry deposition amount in rapid economic development zones was calculated to be totally 6.38 × 103 t using obtained deposition ratios and emissions, with 3.21 × 103 t in Bohai Economic Rim (BER), 2.42 × 103 t in Yangtze River Economic Belt (YREB), 748.43 t in Pearl River Delta (PRD). Generally, crude oil and natural gas extraction, oil processing, synthetic rubber and resin contributed 13.09%, 57.77% and 29.14%, respectively. The proportion of synthetic rubber and resin for dry deposition increased by 5.04%-18.81% compared with VOCs emissions in BER and YREB. In contrast, it declined from 45.52% for emission to 29.86% for deposition due to absolute dominance of small-scale enterprises in PRD. Overall, VOCs control from oil processing was significant, especially in BER.
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Affiliation(s)
- Lingwen Dai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Chemical & Environmental Engineering, China University of Mining and Technology, Beijing 100083, China
| | - Jing Meng
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, 100083, Beijing 100049, China
| | - Xu Zhao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, 100083, Beijing 100049, China
| | - Qianqian Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, 100083, Beijing 100049, China
| | - Bin Shi
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, 100083, Beijing 100049, China
| | - Mingge Wu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, 100083, Beijing 100049, China
| | - Qifan Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, 100083, Beijing 100049, China
| | - Guijin Su
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, 100083, Beijing 100049, China.
| | - Jian Hu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, 100083, Beijing 100049, China
| | - Xinqian Shu
- School of Chemical & Environmental Engineering, China University of Mining and Technology, Beijing 100083, China
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5
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Sharkey SM, Williams BJ, Parker KM. Herbicide Drift from Genetically Engineered Herbicide-Tolerant Crops. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:15559-15568. [PMID: 34813302 DOI: 10.1021/acs.est.1c01906] [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: 06/13/2023]
Abstract
In recent years, off-target herbicide drift has been increasingly reported to lead to damage to nontarget vegetation in the U.S. These reports have coincided with the widespread adoption of genetically modified crops with new herbicide-tolerance traits. Planting crops with these traits may indirectly lead to increased drift both by increasing the use of the corresponding herbicides and by facilitating their use as postemergence herbicides later in the season. While extensive efforts have aimed to reduce herbicide drift, critical uncertainties remain regarding the physiochemical phenomena that drive the entry of herbicides into the atmosphere as well as the atmospheric processes that may influence short- and long-range transport. Resolving these uncertainties will support the development of effective approaches to reduce herbicide drift.
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Affiliation(s)
- Stephen M Sharkey
- Department of Energy, Environmental, and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Brent J Williams
- Department of Energy, Environmental, and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Kimberly M Parker
- Department of Energy, Environmental, and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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6
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Doak AG, Christiansen M, Alwe HD, Bertram TH, Carmichael G, Cleary P, Czarnetzki AC, Dickens AF, Janssen M, Kenski D, Millet DB, Novak GA, Pierce BR, Stone EA, Long RW, Vermeuel MP, Wagner TJ, Valin L, Stanier CO. Characterization of ground-based atmospheric pollution and meteorology sampling stations during the Lake Michigan Ozone Study 2017. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2021; 71:866-889. [PMID: 33689601 PMCID: PMC10068588 DOI: 10.1080/10962247.2021.1900000] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The Lake Michigan Ozone Study 2017 (LMOS 2017) in May and June 2017 enabled study of transport, emissions, and chemical evolution related to ozone air pollution in the Lake Michigan airshed. Two highly instrumented ground sampling sites were part of a wider sampling strategy of aircraft, shipborne, and ground-based mobile sampling. The Zion, Illinois site (on the coast of Lake Michigan, 67 km north of Chicago) was selected to sample higher NOx air parcels having undergone less photochemical processing. The Sheboygan, Wisconsin site (on the coast of Lake Michigan, 211 km north of Chicago) was selected due to its favorable location for the observation of photochemically aged plumes during ozone episodes involving southerly winds with lake breeze. The study encountered elevated ozone during three multiday periods. Daytime ozone episode concentrations at Zion were 60 ppb for ozone, 3.8 ppb for NOx, 1.2 ppb for nitric acid, and 8.2 μg m-3 for fine particulate matter. At Sheboygan daytime, ozone episode concentrations were 60 ppb for ozone, 2.6 ppb for NOx, and 3.0 ppb for NOy. To facilitate informed use of the LMOS 2017 data repository, we here present comprehensive site description, including airmass influences during high ozone periods of the campaign, overview of meteorological and pollutant measurements, analysis of continuous emission monitor data from nearby large point sources, and characterization of local source impacts from vehicle traffic, large point sources, and rail. Consistent with previous field campaigns and the conceptual model of ozone episodes in the area, trajectories from the southwest, south, and lake breeze trajectories (south or southeast) were overrepresented during pollution episodes. Local source impacts from vehicle traffic, large point sources, and rail were assessed and found to represent less than about 15% of typical concentrations measured. Implications for model-observation comparison and design of future field campaigns are discussed.Implications: The Lake Michigan Ozone Study 2017 (LMOS 2017) was conducted along the western shore of Lake Michigan, and involved two well-instrumented coastal ground sites (Zion, IL, and Sheboygan, WI). LMOS 2017 data are publicly available, and this paper provides detailed site characterization and measurement summary to enable informed use of repository data. Minor local source impacts were detected but were largely confined to nighttime conditions of less interest for ozone episode analysis and modeling. The role of these sites in the wider field campaign and their detailed description facilitates future campaign planning, informed data repository use, and model-observation comparison.
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Affiliation(s)
- Austin G. Doak
- Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA, USA
| | - Megan Christiansen
- Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA, USA
- IIHR Hydroscience and Engineering, University of Iowa, Iowa City, IA, USA
- Center for Global and Regional Environmental Research, University of Iowa, Iowa City, IA, USA
| | - Hariprasad D. Alwe
- Department of Soil, Water, and Climate, University of Minnesota, Saint Paul, MN, USA
| | - Timothy H. Bertram
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Gregory Carmichael
- Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA, USA
- Center for Global and Regional Environmental Research, University of Iowa, Iowa City, IA, USA
| | - Patricia Cleary
- Department of Chemistry and Biochemistry, University of Wisconsin-Eau Claire, Eau Claire, WI, USA
| | - Alan C. Czarnetzki
- Department of Earth and Environmental Sciences, University of Northern Iowa, Cedar Falls, IA, USA
| | | | - Mark Janssen
- Lake Michigan Air Directors Consortium, Rosemont, IL, USA
| | - Donna Kenski
- Lake Michigan Air Directors Consortium, Rosemont, IL, USA
| | - Dylan B. Millet
- Department of Soil, Water, and Climate, University of Minnesota, Saint Paul, MN, USA
| | - Gordon A. Novak
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Bradley R. Pierce
- Space Science and Engineering Center, University of Wisconsin-Madison, Madison, WI, USA
| | | | - Russell W. Long
- United States Environmental Protection Agency, Durham, NC, USA
| | | | - Timothy J. Wagner
- Space Science and Engineering Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Lukas Valin
- United States Environmental Protection Agency, Durham, NC, USA
| | - Charles O. Stanier
- Department of Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA, USA
- IIHR Hydroscience and Engineering, University of Iowa, Iowa City, IA, USA
- Center for Global and Regional Environmental Research, University of Iowa, Iowa City, IA, USA
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7
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Heald CL, Gouw JD, Goldstein AH, Guenther AB, Hayes PL, Hu W, Isaacman-VanWertz G, Jimenez JL, Keutsch FN, Koss AR, Misztal PK, Rappenglück B, Roberts JM, Stevens PS, Washenfelder RA, Warneke C, Young CJ. Contrasting Reactive Organic Carbon Observations in the Southeast United States (SOAS) and Southern California (CalNex). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:14923-14935. [PMID: 33205951 DOI: 10.1021/acs.est.0c05027] [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: 06/11/2023]
Abstract
Despite the central role of reactive organic carbon (ROC) in the formation of secondary species that impact global air quality and climate, our assessment of ROC abundance and impacts is challenged by the diversity of species that contribute to it. We revisit measurements of ROC species made during two field campaigns in the United States: the 2013 SOAS campaign in forested Centreville, AL, and the 2010 CalNex campaign in urban Pasadena, CA. We find that average measured ROC concentrations are about twice as high in Pasadena (73.8 μgCsm-3) than in Centreville (36.5 μgCsm-3). However, the OH reactivity (OHR) measured at these sites is similar (20.1 and 19.3 s-1). The shortfall in OHR when summing up measured contributions is 31%, at Pasadena and 14% at Centreville, suggesting that there may be a larger reservoir of unmeasured ROC at the former site. Estimated O3 production and SOA potential (defined as concentration × yield) are both higher during CalNex than SOAS. This analysis suggests that the ROC in urban California is less reactive, but due to higher concentrations of oxides of nitrogen and hydroxyl radicals, is more efficient in terms of O3 and SOA production, than in the forested southeastern U.S.
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Affiliation(s)
- Colette L Heald
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Joost de Gouw
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
| | - Allen H Goldstein
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720, United States
- Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720, United States
| | - Alex B Guenther
- Department of Earth System Science, University of California, Irvine,California 92697, United States
| | - Patrick L Hayes
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Weiwei Hu
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
| | - Gabriel Isaacman-VanWertz
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720, United States
| | - Jose L Jimenez
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
| | - Frank N Keutsch
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Abigail R Koss
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, United States
| | - Pawel K Misztal
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720, United States
| | - Bernhard Rappenglück
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, Texas 77204, United States
| | - James M Roberts
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, United States
| | - Philip S Stevens
- O'Neill School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana 47405, United States
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Rebecca A Washenfelder
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, United States
| | - Carsten Warneke
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, United States
| | - Cora J Young
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
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8
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Canaval E, Millet DB, Zimmer I, Nosenko T, Georgii E, Partoll EM, Fischer L, Alwe HD, Kulmala M, Karl T, Schnitzler JP, Hansel A. Rapid conversion of isoprene photooxidation products in terrestrial plants. COMMUNICATIONS EARTH & ENVIRONMENT 2020; 1:44. [PMID: 33615239 PMCID: PMC7894407 DOI: 10.1038/s43247-020-00041-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 09/22/2020] [Indexed: 05/21/2023]
Abstract
Isoprene is emitted from the biosphere into the atmosphere, and may strengthen the defense mechanisms of plants against oxidative and thermal stress. Once in the atmosphere, isoprene is rapidly oxidized, either to isoprene-hydroxy-hydroperoxides (ISOPOOH) at low levels of nitrogen oxides, or to methyl vinyl ketone (MVK) and methacrolein at high levels. Here we combine uptake rates and deposition velocities that we obtained in laboratory experiments with observations in natural forests to show that 1,2-ISOPOOH deposits rapidly into poplar leaves. There, it is converted first to cytotoxic MVK and then most probably through alkenal/ one oxidoreductase (AOR) to less toxic methyl ethyl ketone (MEK). This detoxification process is potentially significant globally because AOR enzymes are ubiquitous in terrestrial plants. Our simulations with a global chemistry-transport model suggest that around 6.5 Tg yr- of MEK are re-emitted to the atmosphere. This is the single largest MEK source presently known, and recycles 1.5% of the original isoprene flux. Eddy covariance flux measurements of isoprene and MEK over different forest ecosystems confirm that MEK emissions can reach 1-2% those of isoprene. We suggest that detoxification processes in plants are one of the most important sources of oxidized volatile organic compounds in the atmosphere.
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Affiliation(s)
- Eva Canaval
- Department of Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - Dylan B Millet
- Department of Soil, Water and Climate, University of Minnesota, 439 Borlaug Hall, St. Paul, MN, USA
| | - Ina Zimmer
- Research Unit Environmental Simulation (EUS), Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Tetyana Nosenko
- Research Unit Environmental Simulation (EUS), Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Elisabeth Georgii
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Eva Maria Partoll
- Department of Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - Lukas Fischer
- Department of Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - Hariprasad D Alwe
- Department of Soil, Water and Climate, University of Minnesota, 439 Borlaug Hall, St. Paul, MN, USA
| | - Markku Kulmala
- Institute for Atmospheric and Earth System Research (INAR)/Physics, University of Helsinki, Gustaf Hällströmin katu 2, 00014 Helsinki, Finland
| | - Thomas Karl
- Department of Atmospheric and Cryospheric Sciences, University of Innsbruck, Innrain 52f, 6020 Innsbruck, Austria
| | - Jörg-Peter Schnitzler
- Research Unit Environmental Simulation (EUS), Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Armin Hansel
- Department of Ion Physics and Applied Physics, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
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9
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Farmer DK, Riches M. Measuring Biosphere-Atmosphere Exchange of Short-Lived Climate Forcers and Their Precursors. Acc Chem Res 2020; 53:1427-1435. [PMID: 32687308 DOI: 10.1021/acs.accounts.0c00203] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Exchange of reactive trace gases over the biosphere is a key source of reactive organic carbon to the atmosphere and thus influences the formation of both ozone (O3) and secondary organic aerosol (SOA). Both O3 and aerosol particles are short-lived climate forcers and impact the radiative balance of the planet, and their sources and sinks are chemically complex. However, the biosphere also acts as a deposition sink for organic and inorganic compounds, including O3, aerosols, and their precursors. Wet and dry deposition provides a key lever on the lifetime of trace gases and particles in the atmosphere and thus on their potential to influence the radiative balance of the planet. The fluxes of reactive trace gases and particles are part of an atmospheric biogeochemical cycle that includes feedbacks through drought and other climate components.Recent advances in measurement techniques have enabled new field observations of trace gas and particle fluxes. Our method development has focused on the leaf, branch, and forest level, although satellite measurements coupled to modeling also provide promising new approaches to constraining trace gas fluxes. Leaf chamber measurements of volatile organic compound (VOC) emissions highlight leaf-to-leaf and plant-to-plant variability in both photosynthesis and emissions of individual VOCs, in addition to differences in emissions across different isomers of monoterpenes. Isomers obviously have different chemical properties (e.g., reaction rates with OH radicals, SOA yield) and thus hold different potentials as precursors for short-lived climate forcers.The biosphere acts as both sources and sinks of the oxidation products of monoterpenes and other biogenic VOCs. Developments in chemical ionization mass spectrometry have recently enabled measurements of volatile organic acids, which demonstrate a strong temperature-dependent ecosystem source, as well as a source from in-canopy chemistry. In-canopy chemistry also influences particle fluxes, although deposition should dominate their net exchange. Our field observations of chemically resolved particle fluxes demonstrate the simultaneous, competing processes driving forest exchange. To separate out these competing processes, we use black carbon as an inert tracer for particle deposition. Our recent measurements demonstrate the importance of wet deposition in controlling particle lifetime in the atmosphere. Overall, new measurement techniques have enabled both field and laboratory observations to improve our understanding of biosphere-atmosphere interactions and their influence on climate processes.
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Affiliation(s)
- Delphine K. Farmer
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Mj Riches
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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10
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Angot H, McErlean K, Hu L, Millet DB, Hueber J, Cui K, Moss J, Wielgasz C, Milligan T, Ketcherside D, Bret-Harte MS, Helmig D. Biogenic volatile organic compound ambient mixing ratios and emission rates in the Alaskan Arctic tundra. BIOGEOSCIENCES (ONLINE) 2020; 17:6219-6236. [PMID: 35222652 PMCID: PMC8872036 DOI: 10.5194/bg-17-6219-2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Rapid Arctic warming, a lengthening growing season, and the increasing abundance of biogenic volatile-organic-compound-emitting shrubs are all anticipated to increase atmospheric biogenic volatile organic compounds (BVOCs) in the Arctic atmosphere, with implications for atmospheric oxidation processes and climate feedbacks. Quantifying these changes requires an accurate understanding of the underlying processes driving BVOC emissions in the Arctic. While boreal ecosystems have been widely studied, little attention has been paid to Arctic tundra environments. Here, we report terpenoid (isoprene, monoterpenes, and sesquiterpenes) ambient mixing ratios and emission rates from key dominant vegetation species at Toolik Field Station (TFS; 68°38' N, 149°36' W) in northern Alaska during two back-to-back field campaigns (summers of 2018 and 2019) covering the entire growing season. Isoprene ambient mixing ratios observed at TFS fell within the range of values reported in the Eurasian taiga (0-500 parts per trillion by volume - pptv), while monoterpene and sesquiterpene ambient mixing ratios were respectively close to and below the instrumental quantification limit (~ 2 pptv). Isoprene surface emission rates ranged from 0.2 to 2250 μgC m-2 h-1 (mean of 85 μgC m-2 h-1) and monoterpene emission rates remained, on average, below 1 μgC m-2 h-1 over the course of the study. We further quantified the temperature dependence of isoprene emissions from local vegetation, including Salix spp. (a known isoprene emitter), and compared the results to predictions from the Model of Emissions of Gases and Aerosols from Nature version 2.1 (MEGAN2.1). Our observations suggest a 180 %-215 % emission increase in response to a 3-4°C warming, and the MEGAN2.1 temperature algorithm exhibits a close fit with observations for enclosure temperatures in the 0-30°C range. The data presented here provide a baseline for investigating future changes in the BVOC emission potential of the under-studied Arctic tundra environment.
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Affiliation(s)
- Hélène Angot
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO, USA
| | - Katelyn McErlean
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO, USA
| | - Lu Hu
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, USA
| | - Dylan B. Millet
- Department of Soil, Water, and Climate, University of Minnesota, Minneapolis–Saint Paul, MN, USA
| | - Jacques Hueber
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO, USA
| | - Kaixin Cui
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO, USA
| | - Jacob Moss
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO, USA
| | - Catherine Wielgasz
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, USA
| | - Tyler Milligan
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO, USA
| | - Damien Ketcherside
- Department of Chemistry and Biochemistry, University of Montana, Missoula, MT, USA
| | | | - Detlev Helmig
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO, USA
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11
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Chaliyakunnel S, Millet DB, Chen X. Constraining Emissions of Volatile Organic Compounds Over the Indian Subcontinent Using Space-Based Formaldehyde Measurements. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2019; 124:10525-10545. [PMID: 33614368 PMCID: PMC7894393 DOI: 10.1029/2019jd031262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 08/26/2019] [Indexed: 06/11/2023]
Abstract
India is an air pollution mortality hot spot, but regional emissions are poorly understood. We present a high-resolution nested chemical transport model (GEOS-Chem) simulation for the Indian subcontinent and use it to interpret formaldehyde (HCHO) observations from two satellite sensors (OMI and GOME-2A) in terms of constraints on regional volatile organic compound (VOC) emissions. We find modeled biogenic VOC emissions to be overestimated by ~30-60% for most locations and seasons, and derive a best estimate biogenic flux of 16 Tg C/year subcontinent-wide for year 2009. Terrestrial vegetation provides approximately half the total VOC flux in our base-case inversions (full uncertainty range: 44-65%). This differs from prior understanding, in which biogenic emissions represent >70% of the total. Our derived anthropogenic VOC emissions increase slightly (13-16% in the base case, for a subcontinent total of 15 Tg C/year in 2009) over RETRO year 2000 values, with some larger regional discrepancies. The optimized anthropogenic emissions agree well with the more recent CEDS inventory, both subcontinent-wide (within 2%) and regionally. An exception is the Indo-Gangetic Plain, where we find an underestimate for both RETRO and CEDS. Anthropogenic emissions thus constitute 37-50% of the annual regional VOC source in our base-case inversions and exceed biogenic emissions over the Indo-Gangetic Plain, West India, and South India, and over the entire subcontinent during winter and post-monsoon. Fires are a minor fraction (<7%) of the total regional VOC source in the prior and optimized model. However, evidence suggests that VOC emissions in the fire inventory used here (GFEDv4) are too low over the Indian subcontinent.
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Affiliation(s)
- Sreelekha Chaliyakunnel
- Department of Soil, Water, and Climate, University of Minnesota, Twin Cities, St. Paul, MN, USA
| | - Dylan B Millet
- Department of Soil, Water, and Climate, University of Minnesota, Twin Cities, St. Paul, MN, USA
| | - Xin Chen
- Department of Soil, Water, and Climate, University of Minnesota, Twin Cities, St. Paul, MN, USA
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12
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Chen X, Millet DB, Singh HB, Wisthaler A, Apel EC, Atlas EL, Blake DR, Bourgeois I, Brown SS, Crounse JD, de Gouw JA, Flocke FM, Fried A, Heikes BG, Hornbrook RS, Mikoviny T, Min KE, Müller M, Neuman JA, O'Sullivan DW, Peischl J, Pfister GG, Richter D, Roberts JM, Ryerson TB, Shertz SR, Thompson CR, Treadaway V, Veres PR, Walega J, Warneke C, Washenfelder RA, Weibring P, Yuan B. On the sources and sinks of atmospheric VOCs: an integrated analysis of recent aircraft campaigns over North America. ATMOSPHERIC CHEMISTRY AND PHYSICS 2019; 19:9097-9123. [PMID: 33688334 PMCID: PMC7939023 DOI: 10.5194/acp-19-9097-2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We apply a high-resolution chemical transport model (GEOS-Chem CTM) with updated treatment of volatile organic compounds (VOCs) and a comprehensive suite of airborne datasets over North America to (i) characterize the VOC budget and (ii) test the ability of current models to capture the distribution and reactivity of atmospheric VOCs over this region. Biogenic emissions dominate the North American VOC budget in the model, accounting for 70 % and 95 % of annually emitted VOC carbon and reactivity, respectively. Based on current inventories anthropogenic emissions have declined to the point where biogenic emissions are the dominant summertime source of VOC reactivity even in most major North American cities. Methane oxidation is a 2x larger source of nonmethane VOCs (via production of formaldehyde and methyl hydroperoxide) over North America in the model than are anthropogenic emissions. However, anthropogenic VOCs account for over half of the ambient VOC loading over the majority of the region owing to their longer aggregate lifetime. Fires can be a significant VOC source episodically but are small on average. In the planetary boundary layer (PBL), the model exhibits skill in capturing observed variability in total VOC abundance (R 2 = 0:36) and reactivity (R 2 = 0:54). The same is not true in the free troposphere (FT), where skill is low and there is a persistent low model bias (~ 60 %), with most (27 of 34) model VOCs underestimated by more than a factor of 2. A comparison of PBL: FT concentration ratios over the southeastern US points to a misrepresentation of PBL ventilation as a contributor to these model FT biases. We also find that a relatively small number of VOCs (acetone, methanol, ethane, acetaldehyde, formaldehyde, isoprene C oxidation products, methyl hydroperoxide) drive a large fraction of total ambient VOC reactivity and associated model biases; research to improve understanding of their budgets is thus warranted. A source tracer analysis suggests a current overestimate of biogenic sources for hydroxyacetone, methyl ethyl ketone and glyoxal, an underestimate of biogenic formic acid sources, and an underestimate of peroxyacetic acid production across biogenic and anthropogenic precursors. Future work to improve model representations of vertical transport and to address the VOC biases discussed are needed to advance predictions of ozone and SOA formation.
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Affiliation(s)
- Xin Chen
- Department of Soil, Water, and Climate, University of Minnesota, Minneapolis-Saint Paul, MN, USA
| | - Dylan B. Millet
- Department of Soil, Water, and Climate, University of Minnesota, Minneapolis-Saint Paul, MN, USA
| | | | - Armin Wisthaler
- Institute for Ion Physics and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria
- Department of Chemistry, University of Oslo, Oslo, Norway
| | - Eric C. Apel
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Elliot L. Atlas
- Department of Atmospheric Sciences, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
| | - Donald R. Blake
- Department of Chemistry, University of California, Irvine, Irvine, CA, USA
| | - Ilann Bourgeois
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - Steven S. Brown
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - John D. Crounse
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Joost A. de Gouw
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - Frank M. Flocke
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Alan Fried
- Institute of Arctic & Alpine Research, University of Colorado, Boulder, CO, USA
| | - Brian G. Heikes
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA
| | - Rebecca S. Hornbrook
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Tomas Mikoviny
- Department of Chemistry, University of Oslo, Oslo, Norway
| | - Kyung-Eun Min
- School of Earth Science and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju, South Korea
| | - Markus Müller
- Institute for Ion Physics and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria
| | - J. Andrew Neuman
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | | | - Jeff Peischl
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - Gabriele G. Pfister
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Dirk Richter
- Institute of Arctic & Alpine Research, University of Colorado, Boulder, CO, USA
| | - James M. Roberts
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Thomas B. Ryerson
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - Stephen R. Shertz
- Atmospheric Chemistry Observations & Modeling Laboratory, National Center for Atmospheric Research, Boulder, CO, USA
| | - Chelsea R. Thompson
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | - Victoria Treadaway
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA
| | - Patrick R. Veres
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
| | - James Walega
- Institute of Arctic & Alpine Research, University of Colorado, Boulder, CO, USA
| | - Carsten Warneke
- Chemical Sciences Division, NOAA Earth System Research Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
| | | | - Petter Weibring
- Institute of Arctic & Alpine Research, University of Colorado, Boulder, CO, USA
| | - Bin Yuan
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China
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13
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Alwe HD, Millet DB, Chen X, Raff JD, Payne ZC, Fledderman K. Oxidation of Volatile Organic Compounds as the Major Source of Formic Acid in a Mixed Forest Canopy. GEOPHYSICAL RESEARCH LETTERS 2019; 46:2940-2948. [PMID: 31068737 PMCID: PMC6487833 DOI: 10.1029/2018gl081526] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/24/2019] [Accepted: 02/15/2019] [Indexed: 05/22/2023]
Abstract
Formic acid (HCOOH) is among the most abundant carboxylic acids in the atmosphere, but its budget is poorly understood. We present eddy flux, vertical gradient, and soil chamber measurements from a mixed forest and apply the data to better constrain HCOOH source/sink pathways. While the cumulative above-canopy flux was downward, HCOOH exchange was bidirectional, with extended periods of net upward and downward flux. Net above-canopy fluxes were mostly upward during warmer/drier periods. The implied gross canopy HCOOH source corresponds to 3% and 38% of observed isoprene and monoterpene carbon emissions and is 15× underestimated in a state-of-science atmospheric model (GEOS-Chem). Gradient and soil chamber measurements identify the canopy layer as the controlling source of HCOOH or its precursors to the forest environment; below-canopy sources were minor. A correlation analysis using an ensemble of marker volatile organic compounds suggests that secondary formation, not direct emission, is the major source driving ambient HCOOH.
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Affiliation(s)
- Hariprasad D. Alwe
- Department of Soil, Water, and ClimateUniversity of Minnesota, Twin CitiesSaint PaulMNUSA
| | - Dylan B. Millet
- Department of Soil, Water, and ClimateUniversity of Minnesota, Twin CitiesSaint PaulMNUSA
| | - Xin Chen
- Department of Soil, Water, and ClimateUniversity of Minnesota, Twin CitiesSaint PaulMNUSA
| | - Jonathan D. Raff
- School of Public and Environmental AffairsIndiana UniversityBloomingtonINUSA
- Department of ChemistryIndiana UniversityBloomingtonINUSA
| | | | - Kathryn Fledderman
- School of Public and Environmental AffairsIndiana UniversityBloomingtonINUSA
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