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Shang Y, Luo SN. Insights into the role of the H-abstraction reaction kinetics of amines in understanding their degeneration fates under atmospheric and combustion conditions. Phys Chem Chem Phys 2024. [PMID: 39028293 DOI: 10.1039/d4cp02187h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Amines, a class of prototypical volatile organic compounds, have garnered considerable interest within the context of atmospheric and combustion chemistry due to their substantial contributions to the formation of hazardous pollutants in the atmosphere. In the current energy landscape, the implementation of carbon-neutral energy and strategic initiatives leads to generation of new amine sources that cannot be overlooked in terms of the emission scale. To reduce the emission level of amines from their sources and mitigate their impact on the formation of harmful substances, a comprehensive understanding of the fundamental reaction kinetics during the degeneration process of amines is imperative. This perspective article first presents an overview of both traditional amine sources and emerging amine sources within the context of carbon peaking and carbon neutrality and then highlights the importance of H-abstraction reactions in understanding the atmospheric and combustion chemistry of amines from the perspective of reaction kinetics. Subsequently, the current experimental and theoretical techniques for investigating the H-abstraction reactions of amines are introduced, and a concise summary of research endeavors made in this field over the past few decades is provided. In order to provide accurate kinetic parameters of the H-abstraction reactions of amines, advanced kinetic calculations are performed using the multi-path canonical variational theory combined with the small-curvature tunneling and specific-reaction parameter methods. By comparing with the literature data, current kinetic calculations are comprehensively evaluated, and these validated data are valuable for the development of the reaction mechanism of amines.
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Affiliation(s)
- Yanlei Shang
- Energy Research Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong, 250014, P. R. China.
- School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan, 610031, P. R. China
- Key Laboratory of Extreme Material Dynamics Technology, Chengdu, Sichuan 610031, P. R. China
| | - S N Luo
- School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan, 610031, P. R. China
- Key Laboratory of Extreme Material Dynamics Technology, Chengdu, Sichuan 610031, P. R. China
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2
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Shutter JD, Millet DB, Wells KC, Payne VH, Nowlan CR, Abad GG. Interannual changes in atmospheric oxidation over forests determined from space. SCIENCE ADVANCES 2024; 10:eadn1115. [PMID: 38748807 PMCID: PMC11095458 DOI: 10.1126/sciadv.adn1115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 04/10/2024] [Indexed: 05/19/2024]
Abstract
The hydroxyl radical (OH) is the central oxidant in Earth's troposphere, but its temporal variability is poorly understood. We combine 2012-2020 satellite-based isoprene and formaldehyde measurements to identify coherent OH changes over temperate and tropical forests with attribution to emission trends, biotic stressors, and climate. We identify a multiyear OH decrease over the Southeast United States and show that with increasingly hot/dry summers the regional chemistry could become even less oxidizing depending on competing temperature/drought impacts on isoprene. Furthermore, while global mean OH decreases during El Niño, we show that near-field effects over tropical rainforests can alternate between high/low OH anomalies due to opposing fire and biogenic emission impacts. Results provide insights into how atmospheric oxidation will evolve with changing emissions and climate.
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Affiliation(s)
- Joshua D. Shutter
- Department of Soil, Water, and Climate, University of Minnesota, St. Paul, MN 55108, USA
| | - Dylan B. Millet
- Department of Soil, Water, and Climate, University of Minnesota, St. Paul, MN 55108, USA
| | - Kelley C. Wells
- Department of Soil, Water, and Climate, University of Minnesota, St. Paul, MN 55108, USA
| | - Vivienne H. Payne
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91011, USA
| | - Caroline R. Nowlan
- Center for Astrophysics | Harvard & Smithsonian, Cambridge, MA 02138, USA
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3
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Jiang J, McCartt AD. Mid-infrared trace detection with parts-per-quadrillion quantitation accuracy: Expanding frontiers of radiocarbon sensing. Proc Natl Acad Sci U S A 2024; 121:e2314441121. [PMID: 38513090 PMCID: PMC11009668 DOI: 10.1073/pnas.2314441121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 02/08/2024] [Indexed: 03/23/2024] Open
Abstract
Detection sensitivity is a critical characteristic to consider during selection of spectroscopic techniques. However, high sensitivity alone is insufficient for spectroscopic measurements in spectrally congested regions. Two-color cavity ringdown spectroscopy (2C-CRDS), based on intra-cavity pump-probe detection, simultaneously achieves high detection sensitivity and selectivity. This combination enables mid-infrared detection of radiocarbon dioxide ([Formula: see text]CO[Formula: see text]) molecules in room-temperature CO[Formula: see text] samples, with 1.4 parts-per-quadrillion (ppq, 10[Formula: see text]) sensitivity (average measurement precision) and 4.6-ppq quantitation accuracy (average calibrated measurement error for 21 samples from four separate trials) demonstrated on samples with [Formula: see text]C/C up to [Formula: see text]1.5[Formula: see text] natural abundance ([Formula: see text]1,800 ppq). These highly reproducible measurements, which are the most sensitive and quantitatively accurate in the mid-infrared, are accomplished despite the presence of orders-of-magnitude stronger, one-photon signals from other CO[Formula: see text] isotopologues. This is a major achievement in laser spectroscopy. A room-temperature-operated, compact, and low-cost 2C-CRDS sensor for [Formula: see text]CO[Formula: see text] benefits a wide range of scientific fields that utilize [Formula: see text]C for dating and isotope tracing, most notably atmospheric [Formula: see text]CO[Formula: see text] monitoring to track CO[Formula: see text] emissions from fossil fuels. The 2C-CRDS technique significantly enhances the general utility of high-resolution mid-infrared detection for analytical measurements and fundamental chemical dynamics studies.
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Affiliation(s)
- Jun Jiang
- Center for Accelerator Mass Spectrometry, Atmospheric, Earth, and Energy Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA94550
| | - A. Daniel McCartt
- Center for Accelerator Mass Spectrometry, Atmospheric, Earth, and Energy Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA94550
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4
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Zhang M, Hou H, Wang B. Theoretical Study on the Mechanisms and Kinetics of Atmospheric Oxidation of Tetrafluoropropyne and Its Analogues. J Phys Chem A 2024; 128:1511-1522. [PMID: 38362878 DOI: 10.1021/acs.jpca.3c08331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Tetrafluoropropyne (C3F4) is a potential dielectric in various electrical insulating equipment to replace the most potent industrial greenhouse gas, sulfur hexafluoride. Atmospheric oxidation of C3F4 by OH radicals in the presence of molecular O2 has been investigated theoretically in order to clarify the lifetime and degradation products at mechanistic and kinetic aspects. Energetic minimum-energy pathways for the C3F4 + OH/O2 reactions were calculated in detail using various theoretical methods including density functional M06-2X and CCSD for geometries, CBS-QB3, CCSD(T), and multireference RS2 with extrapolation to the complete basis-set limit for energies. It has been demonstrated that the C3F4 + OH reaction takes place via the bifurcated C-O addition/elimination routes leading to CF3C(OH)═CF and CF3C═C(OH)F radical adducts, where the latter is more preferable in view of the difference in barrier heights (1.3 vs 0.3 kcal/mol), followed by H-migration, HF-elimination, and C-C and C-F bond fission. The atmospheric lifetime of C3F4 was estimated to be about 13 days, which is indicative of a very short-lived substance in the atmosphere. Further degradation of the energy-rich C3F4OH* intermediates by O2 takes place spontaneously in view of the successive barrier-free and highly exothermic pathways, producing a variety of fluorinated acids, anhydrides, biacetyls, and regenerating OH radicals. For comparison, the reactions of C3H4, CF3CCH, and CH3CCF with OH radicals were examined to clarify the F-substitution effect. It is revealed that the reactivity of fluoropropynes could be either reduced by CF3 or enhanced by atomic F attached to the acetylenic carbon. The present work provides a fundamental understanding of the reactions of fluoroalkynes with OH/O2. The use of C3F4 as a promising eco-friendly gaseous dielectric alternative to SF6 has been supported.
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Affiliation(s)
- Mi Zhang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People's Republic of China
| | - Hua Hou
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People's Republic of China
| | - Baoshan Wang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People's Republic of China
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5
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Yang X, Wang H, Lu K, Ma X, Tan Z, Long B, Chen X, Li C, Zhai T, Li Y, Qu K, Xia Y, Zhang Y, Li X, Chen S, Dong H, Zeng L, Zhang Y. Reactive aldehyde chemistry explains the missing source of hydroxyl radicals. Nat Commun 2024; 15:1648. [PMID: 38388476 PMCID: PMC10883920 DOI: 10.1038/s41467-024-45885-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 02/06/2024] [Indexed: 02/24/2024] Open
Abstract
Hydroxyl radicals (OH) determine the tropospheric self-cleansing capacity, thus regulating air quality and climate. However, the state-of-the-art mechanisms still underestimate OH at low nitrogen oxide and high volatile organic compound regimes even considering the latest isoprene chemistry. Here we propose that the reactive aldehyde chemistry, especially the autoxidation of carbonyl organic peroxy radicals (R(CO)O2) derived from higher aldehydes, is a noteworthy OH regeneration mechanism that overwhelms the contribution of the isoprene autoxidation, the latter has been proved to largely contribute to the missing OH source under high isoprene condition. As diagnosed by the quantum chemical calculations, the R(CO)O2 radicals undergo fast H-migration to produce unsaturated hydroperoxyl-carbonyls that generate OH through rapid photolysis. This chemistry could explain almost all unknown OH sources in areas rich in both natural and anthropogenic emissions in the warm seasons, and may increasingly impact the global self-cleansing capacity in a future low nitrogen oxide society under carbon neutrality scenarios.
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Affiliation(s)
- Xinping Yang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
- State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Vehicle Emission Control Center, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Haichao Wang
- School of Atmospheric Sciences, Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519082, China
- Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Key Laboratory of Tropical Atmosphere-Ocean System, Ministry of Education, Zhuhai, 519082, China
| | - Keding Lu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China.
| | - Xuefei Ma
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Zhaofeng Tan
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Bo Long
- College of Material Science and Engineering, Guizhou Minzu University, Guizhou, China
| | - Xiaorui Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Chunmeng Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Tianyu Zhai
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Yang Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Kun Qu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Yu Xia
- College of Material Science and Engineering, Guizhou Minzu University, Guizhou, China
| | - Yuqiong Zhang
- College of Material Science and Engineering, Guizhou Minzu University, Guizhou, China
| | - Xin Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Shiyi Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Huabin Dong
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Limin Zeng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Yuanhang Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China.
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6
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Chen D, Zhou L, Liu S, Lian C, Wang W, Liu H, Li C, Liu Y, Luo L, Xiao K, Chen Y, Qiu Y, Tan Q, Ge M, Yang F. Primary sources of HONO vary during the daytime: Insights based on a field campaign. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166605. [PMID: 37640078 DOI: 10.1016/j.scitotenv.2023.166605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/22/2023] [Accepted: 08/25/2023] [Indexed: 08/31/2023]
Abstract
Nitrous acid (HONO) is an established precursor of hydroxyl (OH) radical and has significant impacts on the formation of PM2.5 and O3. Despite extensive research on HONO observation in recent years, knowledge regarding its sources and sinks in urban areas remains inadequate. In this study, we monitored the atmospheric concentrations of HONO and related pollutants, including gaseous nitric acid and particulate nitrate, simultaneously at a supersite in downtown Chengdu, a megacity in southwestern China during spring, when was chosen due to its tolerance for both PM2.5 and O3 pollution. Furthermore, we employed the random forest model to fill the missing data of HONO, which exhibited good predictive performance (R2 = 0.96, RMSE = 0.36 ppbv). During this campaign, the average mixing ratio of HONO was measured to be 1.0 ± 0.7 ppbv. Notably, during periods of high O3 and PM2.5 concentrations, the mixing ratio of HONO was >50 % higher compared to the clean period. We developed a comprehensive parameterization scheme for the HONO budget, and it performed well in simulating diurnal variations of HONO. Based on the HONO budget analysis, we identified different mechanisms that dominate HONO formation at different times of the day. Vehicle emissions and NO2 heterogeneous conversions were found to be the primary sources of HONO during nighttime (21.0 %, 30.2 %, respectively, from 18:00 to 7:00 the next day). In the morning (7:00-12:00), NO2 heterogeneous conversions and the reaction of NO with OH became the main sources (35.0 %, 32.2 %, respectively). However, in the afternoon (12:00-18:00), the heterogeneous photolysis of HNO3 on PM2.5 was identified as the most substantial source of HONO (contributing 52.5 %). This study highlights the significant variations in primary HONO sources throughout the day.
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Affiliation(s)
- Dongyang Chen
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China; College of Carbon Neutrality Future Technology, Sichuan University, Chengdu 610065, China; Sichuan University Yibin Park, Yibin Institute of Industrial Technology, Yibin 644600, China
| | - Li Zhou
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China; College of Carbon Neutrality Future Technology, Sichuan University, Chengdu 610065, China; Sichuan University Yibin Park, Yibin Institute of Industrial Technology, Yibin 644600, China.
| | - Song Liu
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China; College of Carbon Neutrality Future Technology, Sichuan University, Chengdu 610065, China; Sichuan University Yibin Park, Yibin Institute of Industrial Technology, Yibin 644600, China
| | - Chaofan Lian
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Weigang Wang
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Hefan Liu
- Chengdu Academy of Environmental Sciences, Chengdu 610000, China
| | - Chunyuan Li
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China; College of Carbon Neutrality Future Technology, Sichuan University, Chengdu 610065, China; Sichuan University Yibin Park, Yibin Institute of Industrial Technology, Yibin 644600, China
| | - Yuelin Liu
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China; College of Carbon Neutrality Future Technology, Sichuan University, Chengdu 610065, China; Sichuan University Yibin Park, Yibin Institute of Industrial Technology, Yibin 644600, China
| | - Lan Luo
- Sichuan province Chengdu Ecological Environment Monitoring Center Station, Chengdu 610066, China
| | - Kuang Xiao
- Sichuan province Chengdu Ecological Environment Monitoring Center Station, Chengdu 610066, China
| | - Yong Chen
- Sichuan province Chengdu Ecological Environment Monitoring Center Station, Chengdu 610066, China
| | - Yang Qiu
- Department of Industrial Engineering, The Pittsburgh Institute, Sichuan University, Chengdu 610065, China
| | - Qinwen Tan
- Chengdu Academy of Environmental Sciences, Chengdu 610000, China
| | - Maofa Ge
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Fumo Yang
- College of Architecture and Environment, Sichuan University, Chengdu 610065, China; College of Carbon Neutrality Future Technology, Sichuan University, Chengdu 610065, China; Sichuan University Yibin Park, Yibin Institute of Industrial Technology, Yibin 644600, China
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7
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Soleimanian E, Wang Y, Li W, Liu X, Griggs T, Flynn J, Walter PJ, Estes MJ. Understanding ozone episodes during the TRACER-AQ campaign in Houston, Texas: The role of transport and ozone production sensitivity to precursors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 900:165881. [PMID: 37517736 DOI: 10.1016/j.scitotenv.2023.165881] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/01/2023]
Abstract
This study investigated transport pathways and photochemical formation responsible for ozone exceedances during the September 2021 deployment of the Tracking Aerosol Convection Interactions ExpeRiment/Air Quality (TRACER-AQ) campaign in Houston, Texas. We focused on two ozone episodes, September 6th-September 11th ("Episode 1") and September 23rd-September 26th ("Episode 2"), when the maximum daily eight-hour average (MDA8) ozone at surface monitors exceeded 70 ppbv. Long-range transport patterns of air masses during these episodes were from the central/northern US. High-resolution (4 km resolution) trajectory analysis with FLEXible PARTicle (FLEXPART) dispersion model revealed local recirculation of air masses and the accumulation of pollutants across Houston contribute to the ozone exceedances. Comprehensive Air Quality Model with extensions (CAMx) driven by 1.33-km resolution meteorology from the Weather Research and Forecast (WRF) tool simulated elevated ozone production rates during ozone episodes across the Houston metropolitan area, with ozone production hotspots mostly over Houston city and industrial districts of the Houston Ship Channel (HSC). The regional increase in ozone production rates was due to the transport of VOC-rich air masses (via northerly flows) that brought ozone precursors to the region, which ultimately caused a transition in the ozone formation tendency from generally VOC-limited to NOx-limited conditions. However, the city of Houston and the HSC remained in a VOC-limited regime because of local NOx emissions that, to some extent, preponderated the impact of transported VOCs. While approximately 37 % of the elevated ozone production was attributed to local photochemistry, the remaining ∼63 % increase in ozone production was due to the transported ozone to the region during episodes, bringing ozone to the Houston region and contributing to ozone exceedances. The outcomes of this study illustrated the synergy between transport and ozone production, both long-range and local scale, which resulted in ozone exceedances in Houston.
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Affiliation(s)
- Ehsan Soleimanian
- Department of Earth and Atmospheric Sciences, University of Houston, Houston 77204, TX, USA
| | - Yuxuan Wang
- Department of Earth and Atmospheric Sciences, University of Houston, Houston 77204, TX, USA.
| | - Wei Li
- Department of Earth and Atmospheric Sciences, University of Houston, Houston 77204, TX, USA
| | - Xueying Liu
- Department of Earth and Atmospheric Sciences, University of Houston, Houston 77204, TX, USA
| | - Travis Griggs
- Department of Earth and Atmospheric Sciences, University of Houston, Houston 77204, TX, USA
| | - James Flynn
- Department of Earth and Atmospheric Sciences, University of Houston, Houston 77204, TX, USA
| | - Paul J Walter
- Department of Mathematics, St. Edward's University, Austin 78704, TX, USA
| | - Mark J Estes
- Department of Mathematics, St. Edward's University, Austin 78704, TX, USA
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8
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Chang CW, Chen IY, Fittschen C, Luo PL. Measurements of absolute line strength of the ν1 fundamental transitions of OH radical and rate coefficient of the reaction OH + H2O2 with mid-infrared two-color time-resolved dual-comb spectroscopy. J Chem Phys 2023; 159:184203. [PMID: 37962448 DOI: 10.1063/5.0176311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023] Open
Abstract
Absolute line strengths of several transitions in the ν1 fundamental band of the hydroxyl radical (OH) have been measured by simultaneous determination of hydrogen peroxide (H2O2) and OH upon laser photolysis of H2O2. Based on the well-known quantum yield for the generation of OH radicals in the 248-nm photolysis of H2O2, the line strength of the OH radicals can be accurately derived by adopting the line strength of the well-characterized transitions of H2O2 and analyzing the difference absorbance time traces of H2O2 and OH obtained upon laser photolysis. Employing a synchronized two-color dual-comb spectrometer, we measured high-resolution time-resolved absorption spectra of H2O2 near 7.9 µm and the OH radical near 2.9 µm, simultaneously, under varied conditions. In addition to the studies of the line strengths of the selected H2O2 and OH transitions, the kinetics of the reaction between OH and H2O2 were investigated. A pressure-independent rate coefficient kOH+H2O2 was determined to be [1.97 (+0.10/-0.15)] × 10-12 cm3 molecule-1 s-1 at 296 K and compared with other experimental results. By carefully analyzing both high-resolution spectra and temporal absorbance profiles of H2O2 and OH, the uncertainty of the obtained OH line strengths can be achieved down to <10% in this work. Moreover, the proposed two-color time-resolved dual-comb spectroscopy provides a new approach for directly determining the line strengths of transient free radicals and holds promise for investigations on their self-reaction kinetics as well as radical-radical reactions.
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Affiliation(s)
- Che-Wei Chang
- Institute of Atomic and Molecular Sciences Academia Sinica, Taipei 106319, Taiwan
| | - I-Yun Chen
- Institute of Atomic and Molecular Sciences Academia Sinica, Taipei 106319, Taiwan
- Department of Chemistry, National Taiwan University, Taipei 106319, Taiwan
| | - Christa Fittschen
- University Lille, CNRS, UMR 8522, PC2A-Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France
| | - Pei-Ling Luo
- Institute of Atomic and Molecular Sciences Academia Sinica, Taipei 106319, Taiwan
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9
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Cao C, Gentner DR, Commane R, Toledo-Crow R, Schiferl LD, Mak JE. Policy-Related Gains in Urban Air Quality May Be Offset by Increased Emissions in a Warming Climate. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023. [PMID: 37327457 DOI: 10.1021/acs.est.2c05904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Air quality policies have made substantial gains by reducing pollutant emissions from the transportation sector. In March 2020, New York City's activities were severely curtailed in response to the COVID-19 pandemic, resulting in 60-90% reductions in human activity. We continuously measured major volatile organic compounds (VOCs) during January-April 2020 and 2021 in Manhattan. Concentrations of many VOCs decreased significantly during the shutdown with variations in daily patterns reflective of human activity perturbations, resulting in a temporary ∼28% reduction in chemical reactivity. However, the limited effect of these dramatic measures was outweighed by larger increases in VOC-related reactivity during the anomalously warm spring 2021. This emphasizes the diminishing returns from transportation-focused policies alone and the risk of increased temperature-dependent emissions undermining policy-related gains in a warming climate.
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Affiliation(s)
- Cong Cao
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794, United States
| | - Drew R Gentner
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06511, United States
| | - Róisín Commane
- Department of Earth and Environmental Sciences, Columbia University, New York, New York 10027, United States
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, United States
| | - Ricardo Toledo-Crow
- Advanced Science Research Center, City University of New York, New York, New York 10031, United States
| | - Luke D Schiferl
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, United States
| | - John E Mak
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York 11794, United States
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10
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Douroudgari H, Zarepour H, Vahedpour M, Jaberi M, Zarepour M. The atmospheric relevance of primary alcohols and imidogen reactions. Sci Rep 2023; 13:9150. [PMID: 37277419 DOI: 10.1038/s41598-023-35473-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 05/18/2023] [Indexed: 06/07/2023] Open
Abstract
Organic alcohols as very volatile compounds play a crucial role in the air quality of the atmosphere. So, the removal processes of such compounds are an important atmospheric challenge. The main goal of this research is to discover the atmospheric relevance of degradation paths of linear alcohols by imidogen with the aid of simulation by quantum mechanical (QM) methods. To this end, we combine broad mechanistic and kinetic results to get more accurate information and to have a deeper insight into the behavior of the designed reactions. Thus, the main and necessary reaction pathways are explored by well-behaved QM methods for complete elucidation of the studying gaseous reactions. Moreover, the potential energy surfaces as a main factor are computed for easier judging of the most probable pathways in the simulated reactions. Our attempt to find the occurrence of the considered reactions in the atmospheric conditions is completed by precisely evaluating the rate constants of all elementary reactions. All of the computed bimolecular rate constants have a positive dependency on both temperature and pressure. The kinetic results show that H-abstraction from the α carbon is dominant relative to the other sites. Finally, by the results of this study, we conclude that at moderate temperatures and pressures primary alcohols can degrade with imidogen, so they can get atmospheric relevance.
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Affiliation(s)
- Hamed Douroudgari
- Department of Chemistry, University of Zanjan, PO Box 38791-45371, Zanjan, Iran.
| | - Hadi Zarepour
- Department of Chemistry, University of Zanjan, PO Box 38791-45371, Zanjan, Iran
| | - Morteza Vahedpour
- Department of Chemistry, University of Zanjan, PO Box 38791-45371, Zanjan, Iran.
| | - Mahdi Jaberi
- Department of Chemistry, University of Zanjan, PO Box 38791-45371, Zanjan, Iran
| | - Mahdi Zarepour
- Department of Chemistry, University of Zanjan, PO Box 38791-45371, Zanjan, Iran
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11
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Reidy E, Bottorff BP, Rosales CM, Cardoso-Saldaña FJ, Arata C, Zhou S, Wang C, Abeleira A, Hildebrandt Ruiz L, Goldstein AH, Novoselac A, Kahan TF, Abbatt JPD, Vance ME, Farmer DK, Stevens PS. Measurements of Hydroxyl Radical Concentrations during Indoor Cooking Events: Evidence of an Unmeasured Photolytic Source of Radicals. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:896-908. [PMID: 36603843 PMCID: PMC9850917 DOI: 10.1021/acs.est.2c05756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The hydroxyl radical (OH) is the dominant oxidant in the outdoor environment, controlling the lifetimes of volatile organic compounds (VOCs) and contributing to the growth of secondary organic aerosols. Despite its importance outdoors, there have been relatively few measurements of the OH radical in indoor environments. During the House Observations of Microbial and Environmental Chemistry (HOMEChem) campaign, elevated concentrations of OH were observed near a window during cooking events, in addition to elevated mixing ratios of nitrous acid (HONO), VOCs, and nitrogen oxides (NOX). Particularly high concentrations were measured during the preparation of a traditional American Thanksgiving dinner, which required the use of a gas stove and oven almost continually for 6 h. A zero-dimensional chemical model underpredicted the measured OH concentrations even during periods when direct sunlight illuminated the area near the window, which increases the rate of OH production by photolysis of HONO. Interferences with measurements of nitrogen dioxide (NO2) and ozone (O3) suggest that unmeasured photolytic VOCs were emitted during cooking events. The addition of a VOC that photolyzes to produce peroxy radicals (RO2), similar to pyruvic acid, into the model results in better agreement with the OH measurements. These results highlight our incomplete understanding of the nature of oxidation in indoor environments.
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Affiliation(s)
- Emily Reidy
- Department
of Chemistry, Indiana University, Bloomington, Indiana47405, United States
| | - Brandon P. Bottorff
- Department
of Chemistry, Indiana University, Bloomington, Indiana47405, United States
| | - Colleen Marciel
F. Rosales
- O’Neill
School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana47405, United States
| | | | - Caleb Arata
- Department
of Environmental Science, Policy, and Management, University of California, Berkeley, California94720, United States
| | - Shan Zhou
- Department
of Chemistry, Syracuse University, Syracuse, New York13244, United States
| | - Chen Wang
- Department
of Chemistry, University of Toronto, Toronto, OntarioM5S 3H6, Canada
| | - Andrew Abeleira
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado80523, United States
| | - Lea Hildebrandt Ruiz
- McKetta
Department of Chemical Engineering, University
of Texas, Austin, Texas78712, United
States
| | - Allen H. Goldstein
- Department
of Environmental Science, Policy, and Management, University of California, Berkeley, California94720, United States
| | - Atila Novoselac
- Department
of Civil, Architectural, and Environmental Engineering, University of Texas, Austin, Texas78712, United States
| | - Tara F. Kahan
- Department
of Chemistry, Syracuse University, Syracuse, New York13244, United States
- Department
of Chemistry, University of Saskatchewan, Saskatoon, SaskatchewanS7N 5E6, Canada
| | | | - Marina E. Vance
- Department
of Mechanical Engineering, University of
Colorado, Boulder, Colorado80309, United States
| | - Delphine K. Farmer
- Department
of Chemistry, Colorado State University, Fort Collins, Colorado80523, United States
| | - Philip S. Stevens
- Department
of Chemistry, Indiana University, Bloomington, Indiana47405, United States
- O’Neill
School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana47405, United States
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12
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Liu C, Xin Y, Zhang C, Liu J, Liu P, He X, Mu Y. Ambient volatile organic compounds in urban and industrial regions in Beijing: Characteristics, source apportionment, secondary transformation and health risk assessment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 855:158873. [PMID: 36126704 DOI: 10.1016/j.scitotenv.2022.158873] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/09/2022] [Accepted: 09/15/2022] [Indexed: 06/15/2023]
Abstract
Field measurements of volatile organic compounds (VOCs) were conducted simultaneously at an urban site and one industrial park site in Beijing in summer. The VOCs concentrations were 94.3 ± 157.8 ppbv and 20.7 ± 8.9 ppbv for industrial and urban sites, respectively. Alkanes and aromatics were the major contributors to VOCs in industrial site, while oxygenated volatile organic compounds (OVOCs) contributed most in urban site. The most abundant VOC species were n-pentane and formaldehyde for industrial site and urban site, respectively. The calculated ozone formation potential (OFP) and OH loss rates (LOH) were 621.1 ± 1491.9 ppbv (industrial site), 102.9 ± 37.3 ppbv (urban site), 22.0 ± 39.0 s-1 (industrial site) and 5.3 ± 2.2 s-1 (urban site), respectively. Based on the positive matrix factorization (PMF) model, solvent utilization I (34.1 %), solvent utilization II (27.9 %), mixture combustion source (19.3 %), OVOCs related source (9.6 %) and biogenic source (9.1 %) were identified in the industrial site, while OVOCs related source (27.8 %), vehicle exhaust (22.1 %), solvent utilization (19.3 %), coal combustion (16.0 %) and biogenic source (14.8 %) were identified in the urban site. The results of O3-VOCs-NOx sensitivity indicated that O3 formation were respectively under the VOC-limited and NOx-limited conditions in Beijing urban and industrial regions. Additionally, aromatics accounted remarkable SOA formation ability both in the two sites, and SOA potentials of xylene, toluene and ethylbenzene as the indicator species for the solvent utilization in industrial site were remarkable higher than those obtained in urban regions. The hazard index values in the industrial and urban sites were 1.72 and 3.39, respectively, suggesting a high non-carcinogenic risks to the exposed population. Formaldehyde had the highest carcinogenic risks in the two sites, and the cumulative carcinogenic risks in the industrial site and urban site were 1.95 × 10-5 and 1.21 × 10-5, respectively.
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Affiliation(s)
- Chengtang Liu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100085, China
| | - Yanyan Xin
- College of Environmental Engineering, Beijing Forestry University, Beijing 100083, China
| | - Chenglong Zhang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100085, China
| | - Junfeng Liu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100085, China
| | - Pengfei Liu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100085, China
| | - Xiaowei He
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100085, China
| | - Yujing Mu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100085, China.
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13
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Gao Y, Lu K, Zhang Y. Review of technologies and their applications for the speciated detection of RO 2 radicals. J Environ Sci (China) 2023; 123:487-499. [PMID: 36522008 DOI: 10.1016/j.jes.2022.09.028] [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: 03/10/2022] [Revised: 09/17/2022] [Accepted: 09/19/2022] [Indexed: 06/17/2023]
Abstract
Peroxy radicals (RO2), which are formed during the oxidation of volatile organic compounds, play an important role in atmospheric oxidation reactions. Therefore, the measurement of RO2, especially distinct species of RO2 radicals, is important and greatly helps the exploration of atmospheric chemistry mechanisms. Although the speciated detection of RO2 radicals remains challenging, various methods have been developed to study them in detail. These methods can be divided into spectroscopy and mass spectrometry technologies. The spectroscopy methods contain laser-induced fluorescence (LIF), UV-absorption spectroscopy, cavity ring-down spectroscopy (CRDS) and matrix isolation and electron spin resonance (MIESR). The mass spectrometry methods contain chemical ionization atmospheric pressure interface time-of-flight mass spectrometry (CI-APi-TOF), chemical ionization mass spectrometry (CIMS), CI-Orbitrap-MS and the third-generation proton transfer reaction-time-of-flight mass spectrometer (PTR3). This article reviews technologies for the speciated detection of RO2 radicals and the applications of these methods. In addition, a comparison of these techniques and the reaction mechanisms of some key species are discussed. Finally, possible gaps are proposed that could be filled by future research into speciated RO2 radicals.
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Affiliation(s)
- Yue Gao
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Keding Lu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
| | - Yuanhang Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
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14
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Impact of a single water molecule on the atmospheric oxidation of thiophene by hydroperoxyl radical. Sci Rep 2022; 12:18959. [PMID: 36347924 PMCID: PMC9643398 DOI: 10.1038/s41598-022-22831-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 10/19/2022] [Indexed: 11/11/2022] Open
Abstract
Water as an important assistant can alter the reactivity of atmospheric species. This project is designed to investigate the impact of a single water molecule on the atmospheric reactions of aromatic compounds that have not been attended to comprehensively. In the first part, the atmospheric oxidation mechanisms of thiophene initiated by hydroperoxyl radical through a multiwell-multichannel potential energy surface were studied to have useful information about the chemistry of the considered reaction. It was verified that for the thiophene plus HO2 reaction, the addition mechanism is dominant the same as other aromatic compounds. Due to the importance of the subject and the presence of water molecules in the atmosphere with a high concentration that we know as relative humidity, and also the lack of insight into the influence of water on the reactions of aromatic compounds with active atmospheric species, herein, the effect of a single water molecule on the addition pathways of the title reaction is evaluated. In another word, this research explores how water can change the occurrence of reactions of aromatic compounds in the atmosphere. For this, the presence of one water molecule is simulated by higher-level calculations (BD(T) method) through the main interactions with the stationary points of the most probable pathways. The results show that the mechanism of the reaction with water is more complicated than the bare reaction due to the formation of the ring-like structures. Also, water molecule decreases the relative energies of all addition pathways. Moreover, atoms in molecule theory (AIM) along with the kinetic study by the transition state (TST) and the Rice–Ramsperger–Kassel–Marcus (RRKM) theories demonstrate that the overall interactions of a path determine how the rate of that path changes. In this regard, our results establish that the interactions of water with HO2 (thiophene) in the initial complex 1WHA (1WTA or 1WTB) are stronger (weaker) than the sum of its interactions in transition states. Also, for the water-assisted pathways, the ratio of the partition function of the transition state to the partition functions of the reactants is similar to the respective bare reaction. Therefore, the reaction rates of the bare pathways are more than the water-assisted paths that include the 1WHA complex and are less than the paths that involve the 1WTA and 1WTB complexes.
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15
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Lin Y, Wu Y, Lin JJ. Building an oxidation reactor in Taiwan: From volatile organic compounds to secondary organic aerosols. J CHIN CHEM SOC-TAIP 2022. [DOI: 10.1002/jccs.202200470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yen‐Hsiu Lin
- Institute of Atomic and Molecular Sciences, Academia Sinica Taipei Taiwan
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Yen‐Ju Wu
- Institute of Atomic and Molecular Sciences, Academia Sinica Taipei Taiwan
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Jim Jr‐Min Lin
- Institute of Atomic and Molecular Sciences, Academia Sinica Taipei Taiwan
- Department of Chemistry National Taiwan University Taipei Taiwan
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16
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Onel L, Brennan A, Østerstro M FF, Cooke E, Whalley L, Seakins PW, Heard DE. Kinetics and Product Branching Ratio Study of the CH 3O 2 Self-Reaction in the Highly Instrumented Reactor for Atmospheric Chemistry. J Phys Chem A 2022; 126:7639-7649. [PMID: 36227778 PMCID: PMC9620170 DOI: 10.1021/acs.jpca.2c04968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
![]()
The fluorescence assay by gas expansion (FAGE) method
for the measurement
of the methyl peroxy radical (CH3O2) using the
conversion of CH3O2 into methoxy radicals (CH3O) by excess NO, followed by the detection of CH3O, has been used to study the kinetics of the self-reaction of CH3O2. Fourier transform infrared (FTIR) spectroscopy
has been employed to determine the products methanol and formaldehyde
of the self-reaction. The kinetics and product studies were performed
in the Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC)
in the temperature range 268–344 K at 1000 mbar of air. The
product measurements were used to determine the branching ratio of
the reaction channel forming methoxy radicals, rCH3O. A value of 0.34 ± 0.05 (errors at 2σ level)
was determined for rCH3O at 295 K. The
temperature dependence of rCH3O can be
parametrized as rCH3O = 1/{1 + [exp(600
± 85)/T]/(3.9 ± 1.1)}. An overall rate
coefficient of the self-reaction of (2.0 ± 0.9) × 10–13 cm3 molecule–1 s–1 at 295 K was obtained by the kinetic analysis of
the observed second-order decays of CH3O2. The
temperature dependence of the overall rate coefficient can be characterized
by koverall = (9.1 ± 5.3) ×
10–14 × exp((252 ± 174)/T) cm3 molecule–1 s–1. The found values of koverall in the
range 268–344 K are ∼40% lower than the values calculated
using the recommendations of the Jet Propulsion Laboratory and IUPAC,
which are based on the previous studies, all of them utilizing time-resolved
UV–absorption spectroscopy to monitor CH3O2. A modeling study using a complex chemical mechanism to describe
the reaction system showed that unaccounted secondary chemistry involving
Cl species increased the values of koverall in the previous studies using flash photolysis to initiate the chemistry.
The overestimation of the koverall values
by the kinetic studies using molecular modulation to generate CH3O2 can be rationalized by a combination of underestimated
optical absorbance of CH3O2 and unaccounted
CH3O2 losses to the walls of the reaction cells
employed.
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Affiliation(s)
- Lavinia Onel
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Alexander Brennan
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | | | - Ellie Cooke
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Lisa Whalley
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom.,National Centre for Atmospheric Science, University of Leeds, LS2 9JT, United Kingdom
| | - Paul W Seakins
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Dwayne E Heard
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom
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17
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Thuy PT, Quan PM, Duc DX, Son NT. The antioxidative potential of procyanidin B1: DFT (density functional theory) and docking approaches. J Mol Model 2022; 28:356. [PMID: 36222929 DOI: 10.1007/s00894-022-05354-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 10/06/2022] [Indexed: 01/18/2023]
Abstract
Procyanidin B1 is one of the natural dimeric flavonoids. It has established a great role in antioxidative activity. In the current study, we wish to provide crucial information on its antioxidative action by the DFT computational and docking approaches. From point of thermodynamic view, at the M062X/6-311G(d,p) level, the HAT (hydrogen atom transfer) and SPL-ET (sequential proton loss-electron transfer) are principal antioxidative routes of this compound in gas and methanol, respectively. OH groups of two phenyl rings of this molecule are likely to be the best antiradical sites. In the kinetics of the interactions with HOO• radicals, OH groups of phenyl rings have also generated the best ΔG# (Gibbs free energy of activation) and rate constant K. The antioxidative action of procyanidin B1 is further confirmed by its chelation to metal ions, in which complex formation with Cu2+ having lower binding energy is more stable than complex formation with Zn2+. Docking study revealed that the antioxidative activity of procyanidin B1 involved human tyrosinase enzyme inhibition through interaction with essential residues, focusing on the OH groups of two phenyl rings.
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Affiliation(s)
- Phan Thi Thuy
- Faculty of Chemistry, College of Education, Vinh University, 182 Le Duan, Vinh, Nghean, Vietnam
| | - Pham Minh Quan
- Institute of Natural Products Chemistry, Vietnam Academy of Science and Technology (VAST), 18 Hoang Quoc Viet, Caugiay, Hanoi, Vietnam
| | - Dau Xuan Duc
- Faculty of Chemistry, College of Education, Vinh University, 182 Le Duan, Vinh, Nghean, Vietnam
| | - Ninh The Son
- Institute of Chemistry, Vietnam Academy of Science and Technology (VAST), 18 Hoang Quoc Viet, Caugiay, Hanoi, Vietnam.
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18
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Wang C, Zhao W, Fang B, Yang N, Cheng F, Hu X, Chen Y, Zhang W, Fittschen C, Chen W. Portable cavity ring-down spectrometer for an HO 2 radical measurement: instrument's performance and potential improvement using a narrow linewidth laser. OPTICS EXPRESS 2022; 30:37446-37456. [PMID: 36258333 DOI: 10.1364/oe.470296] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 09/13/2022] [Indexed: 06/16/2023]
Abstract
We report the development of a portable cavity ring-down spectrometer (CRDS) for direct and absolute measurement of HO2 radical concentration using a distributed feedback (DFB) diode laser operating at 1506 nm. The spectrometer has a compact design with all optics in a 1000 × 400 × 140 mm3 box. At a pressure of 100 mbar and a ring-down time (τ0) of 136 µs, the detection limit of the CRDS spectrometer was ∼ 7.3 × 107 molecule/cm3 (1σ, 10s). The corresponding detection sensitivity was 1.5 × 10-11 cm-1, which was close to the state-of-the-art performance. By replacing the DFB diode laser with a narrow linewidth erbium-doped fiber (EDF) laser, the amplitude fluctuation caused by the laser phase noise was reduced and the cavity mode injection efficiency was improved. The sensitivity was improved to 3.9 × 10-12 cm-1 with a short data-acquisition time of 0.2 s. Compared with the DFB laser, the improvement was nearly an order of magnitude. The use of the narrow linewidth laser is attractive. The instrument can achieve very high sensitivity without the need for a complex locking technique, ensuring simple and ease of use in future field applications.
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19
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Zhang G, Hu R, Xie P, Lu K, Lou S, Liu X, Li X, Wang F, Wang Y, Yang X, Cai H, Wang Y, Liu W. Intercomparison of OH radical measurement in a complex atmosphere in Chengdu, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:155924. [PMID: 35577098 DOI: 10.1016/j.scitotenv.2022.155924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/03/2022] [Accepted: 05/10/2022] [Indexed: 06/15/2023]
Abstract
Atmospheric oxidation is a driving force of complex air pollution, and accurate hydroxyl radical (OH) measurement is helpful in investigating the radical-cored photooxidation mechanism in the troposphere. A self-developed laser-induced fluorescence instrument by the Anhui Institute of Optics Fine Mechanics, Chinese Academy of Sciences (AIOFM-LIF), was able to measure OH concentration with high sensitivity and good time resolution, and a detection limit of 1.7 × 105 cm-3 (1σ, 30 s). A long-period, multi-level intercomparison of hydroxyl radical (OH) measurements between AIOFM-LIF and PKU-LIF (the Peking University laser-induced fluorescence system) was conducted in Chengdu, China. The measurement between two instruments was in excellent agreement in the 5-min time resolution. Linear regression analysis reported a linear slope of 0.96 with a 0.68 × 106 cm-3 offset, and the correlation coefficient R2 was 0.85. The overall linearity with only a slight offset indicated a negligible influence on OH measurement. No noticeable artifacts from ozonolysis were observed under the condition of high ozone and ozonolysis-related compound concentrations. In addition to the subtraction of background signal through wavelength modulation, the dynamic correction on ozone photolysis interference ensured high intercomparison quality in both relatively constant and rapidly varying periods. Based on the reliability of OHAIOFM and OHPKU, comparisons under different oxidation-related species (NOx, VOCs, O3, PM2.5) levels and typical scenarios (rich-BVOC and high-reactivity) were carried out to evaluate the performance under complex atmospheres. A slightly higher drift was observed in a certain scenario, but the general data variability due to environmental changes did not affect the measurement accuracy. The intercomparison demonstrated that both systems are able to achieve reliable OH data under typical conditions of complex atmospheric pollution in China. Additional improvements are necessary for future intercomparisons in order to enhance the confidence in OH detection accuracy.
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Affiliation(s)
- Guoxian Zhang
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China; University of Science and Technology of China, Hefei, China
| | - Renzhi Hu
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China.
| | - Pinhua Xie
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China; University of Science and Technology of China, Hefei, China; CAS Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China; College of Resources and Environment, University of Chinese Academy of Science, Beijing, China.
| | - Keding Lu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Shengrong Lou
- State Environmental Protection Key Laboratory of the Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai, China
| | - Xiaoyan Liu
- College of Pharmacy, Anhui Medical University, Hefei, China
| | - Xin Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Fengyang Wang
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China
| | - Yihui Wang
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China
| | - Xinping Yang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Haotian Cai
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China
| | - Yue Wang
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China
| | - Wenqing Liu
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China
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20
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Abstract
A human-occupied indoor space shares many similarities with Earth and its atmosphere.
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Affiliation(s)
- Coralie Schoemaecker
- Université de Lille, CNRS, UMR 8522-PC2A-Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France
| | - Nicola Carslaw
- Department of Environment and Geography, University of York, York, UK
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21
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Shi G, Song J. Quantum chemical and theoretical kinetics studies on the reactions of hydroperoxy radical with methanethiol and ethanethiol. COMPUT THEOR CHEM 2022. [DOI: 10.1016/j.comptc.2022.113787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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22
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Shi G, Song J. Theoretical investigation on the mechanisms and kinetics of the reactions of hydroperoxy radical with dimethyl sulphide and ethyl methyl sulphide. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2101561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Gai Shi
- State Key Laboratory of Engines, Tianjin University, Tianjin, People’s Republic of China
| | - Jinou Song
- State Key Laboratory of Engines, Tianjin University, Tianjin, People’s Republic of China
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23
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Paul S, Bari MA. Elucidating sources of VOCs in the Capital Region of New York State: Implications to secondary transformation and public health exposure. CHEMOSPHERE 2022; 299:134407. [PMID: 35341770 DOI: 10.1016/j.chemosphere.2022.134407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/27/2022] [Accepted: 03/21/2022] [Indexed: 06/14/2023]
Abstract
Exposure to ambient volatile organic compounds (VOCs) in urban areas is of interest because of their potential adverse effects to public health. A study was carried out to elucidate ambient sources of VOCs in the Capital Region of New York State for the period 2015-2019. A combined dataset of VOCs and PM2.5 species was used in positive matrix factorization (PMF) model to better interpret the complex nature of different sources. Ten sources were revealed, where background source (3.8 μg/m3, 30%) was the largest contributor to VOCs, followed by petroleum-related emissions (2.9 μg/m3, 22%) and pyrolyzed oxygen (OP)-Elemental Carbon (EC2)-aldehydes-rich (2.7 μg/m3, 21%). Other notable VOC sources included methyl ethyl ketone (MEK)-rich, vehicular traffic, and biomass burning. Both OP-EC2-aldehydes-rich and petroleum-related emissions showed notable contribution to ozone (O3) and secondary organic aerosol (SOA) formation, respectively. Observed mean carcinogenic risk values of benzene and formaldehyde and 95th percentiles risk values of 1,3-butadiene and acetaldehyde were above the USEPA acceptable level of 1x10-6 but below a tolerable risk of 1x10-4. Estimated carcinogenic risk values of OP-EC2-aldehydes-rich, vehicular traffic, background and petroleum-related emissions were above the USEPA acceptable cancer risk and posed greater risk to public health (more than 80% of total carcinogenic risk) compared to other sources. Due to lack of some VOC species data (e.g., alkanes, alkenes, terpenes, alcohols), other urban VOC sources e.g., fugitive emissions, fuel evaporation, unburned fuel were not identified. More work is needed to better understand the contribution of VOC sources to O3 and SOA formation in Albany and surrounding region. Findings can support policy makers in developing appropriate air quality management initiatives for the Capital Region in New York State.
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Chen L, Huang Y, Xue Y, Jia Z, Wang W. Kinetic and Mechanistic Investigations of OH-Initiated Atmospheric Degradation of Methyl Butyl Ketone. J Phys Chem A 2022; 126:2976-2988. [PMID: 35536543 DOI: 10.1021/acs.jpca.2c01126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Methyl butyl ketone (MBK, 2-hexanone) is a common atmospheric oxygenated volatile organic compound (OVOC) owing to broad industrial applications, but its atmospheric oxidation mechanism remains poorly understood. Herein, the detailed mechanisms and kinetic properties of MBK oxidation initiated by OH radicals and subsequent transformation of the resulting intermediates are performed by employing quantum chemical and kinetic modeling methods. The calculations show that H-abstraction at the C4 position of MBK is more favorable than those at the other positions, with the total rate coefficient of k(T) = 4.13 × 10-14 exp(1576/T) cm3 molecule-1 s-1 at 273-400 K. The dominant pathway of unimolecular degradation of the C-centered alkyl radical is 1,2-acyl group migration. For the isomerization of the peroxy radical RO2, 1,5- and 1,6-H shifts are more favorable than 1,3- and 1,4-H shifts. The multiconformer rate coefficient kMC-TST of the first H-shift of the RO2 radical is estimated to be 1.40 × 10-3 s-1 at room temperature. Compared to the H-shifts of analogous aliphatic RO2 radicals, it can be concluded that the carbonyl group enhances the H-shift rates by as much as 2-4 orders of magnitude. The rate coefficients of the RO2 radical reaction with the HO2 radical exhibit a weakly negative temperature dependence, and the pseudo-first-order rate constant k'HO2 = kHO2[HO2] is calculated to be 3.32-22.10 × 10-3 s-1 at ambient temperature. The bimolecular reaction of the RO2 radical with NO leads to the formation of 3-oxo-butanal as the main product with the formation concentration of 2.2-7.4 μg/m3 in urban areas. The predicted pseudo-first-order rate constant k'NO = kNO[NO] is 2.20-9.98 s-1 at room temperature. By comparing the kMC-TST, k'HO2, and k'NO, it can be concluded that reaction with NO is the dominant removal pathway for the RO2 radical formed from the OH-initiated oxidation of MBK. These findings are expected to deepen our understanding of the photochemical oxidation of ketones under realistic atmospheric conditions.
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Affiliation(s)
- Long Chen
- State Key Lab of Loess and Quaternary Geology (SKLLQG), Institute of Earth Environment, Chinese Academy of Sciences (CAS), Xi'an 710061, China.,CAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, China
| | - Yu Huang
- State Key Lab of Loess and Quaternary Geology (SKLLQG), Institute of Earth Environment, Chinese Academy of Sciences (CAS), Xi'an 710061, China.,CAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, China
| | - Yonggang Xue
- State Key Lab of Loess and Quaternary Geology (SKLLQG), Institute of Earth Environment, Chinese Academy of Sciences (CAS), Xi'an 710061, China.,CAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, China
| | - Zhihui Jia
- School of Materials Science and Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710119, China
| | - Wenliang Wang
- School of Chemistry and Chemical Engineering, Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi'an, Shaanxi 710119, China
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Yang N, Fang B, Zhao W, Wang C, Cheng F, Hu X, Chen Y, Zhang W, Ma W, Zhao G, Chen W. Optical-feedback cavity-enhanced absorption spectroscopy for OH radical detection at 2.8 µm using a DFB diode laser. OPTICS EXPRESS 2022; 30:15238-15249. [PMID: 35473250 DOI: 10.1364/oe.456648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/03/2022] [Indexed: 06/14/2023]
Abstract
We report the development of an optical-feedback cavity-enhanced absorption spectroscopy (OF-CEAS) instrument for OH detection at 2.8 μm using a DFB diode laser. Two different approaches, symmetry analysis and wavelength modulation, were performed to achieve laser frequency locking to the cavity mode. Compared with the symmetry analysis method, the wavelength modulation method continuously locked the laser frequency to the cavity mode and eliminated decoupling the laser from the cavity mode. A detection sensitivity of 1.7×10-9 cm-1 was achieved in a 25 s sampling time and was about 3 times better than that of the symmetry analysis method. The corresponding OH detection limit was ∼ 2×108 molecule/cm3. Further improvement can be achieved by using higher reflectivity mirrors and other high-sensitivity approaches, such as frequency modulation spectroscopy and Faraday rotation spectroscopy.
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Shi J, Bao Y, Ren L, Chen Y, Bai Z, Han X. Mass Concentration, Source and Health Risk Assessment of Volatile Organic Compounds in Nine Cities of Northeast China. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19084915. [PMID: 35457782 PMCID: PMC9028055 DOI: 10.3390/ijerph19084915] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 04/08/2022] [Accepted: 04/13/2022] [Indexed: 02/04/2023]
Abstract
From April 2008 to July 2009, ambient measurements of 58 volatile organic compounds (VOCs), including alkanes, alkenes, and aromatics, were conducted in nine industrial cities (Shenyang, Fushun, Changchun, Jilin, Harbin, Daqing, Huludao, Anshan and Tianjin) of the Northeast Region, China (NRC). Daqing had the highest concentration of VOCs (519.68 ± 309.88 μg/m3), followed by Changchun (345.01 ± 170.52 μg/m3), Harbin (231.14 ± 46.69 μg/m3), Jilin (221.63 ± 34.32 μg/m3), Huludao (195.92 ± 103.26 μg/m3), Fushun (135.43 ± 46.01 μg/m3), Anshan (109.68 ± 23.27 μg/m3), Tianjin (104.31 ± 46.04 μg/m3), Shenyang (75.2 ± 40.09 μg/m3). Alkanes constituted the largest percentage (>40%) in concentrations of the quantified VOCs in NRC, and the exception was Tianjin dominated by aromatics (about 52.34%). Although alkanes were the most abundant VOCs at the cities, the most important VOCs contributing to ozone formation potential (OFP) were alkenes and aromatics. Changchun had the highest OFP (537.3 μg/m3), Tianjin had the lowest OFP (111.7 μg/m3). The main active species contributing to OFP in the nine cities were C2~C6 alkanes, C7~C8 aromatic hydrocarbons, individual cities (Daqing) contained n-hexane, propane and other alkane species. Correlation between individual hydrocarbons, B/T ratio and principal component analysis model (PCA) were deployed to explore the source contributions. The results showed that the source of vehicle exhausts was one of the primary sources of VOCs in all nine cities. Additionally, individual cities, such as Daqing, petrochemical industry was founded to be an important source of VOCs. The results gained from this study provided a large of useful information for better understanding the characteristics and sources of ambient VOCs incities of NRC. The non-carcinogenic risk values of the nine cities were within the safe range recognized by the U.S. Environmental Protection Agency (HQ < 1), and the lifetime carcinogenic risk values of benzene were 3.82 × 10−5~1.28 × 10−4, which were higher than the safety range specified by the US Environmental Protection Agency (R < 1.00 × 10−6). The results of risk values indicated that there was a risk of cancer in these cities.
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Affiliation(s)
- Jianwu Shi
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China; (J.S.); (Y.B.); (L.R.)
- National-Regional Engineering Center for Recovery of Waste Gases from Metallurgical and Chemical Industries, Kunming 650500, China
| | - Yuzhai Bao
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China; (J.S.); (Y.B.); (L.R.)
- National-Regional Engineering Center for Recovery of Waste Gases from Metallurgical and Chemical Industries, Kunming 650500, China
| | - Liang Ren
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China; (J.S.); (Y.B.); (L.R.)
| | - Yuanqi Chen
- Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming 650500, China;
| | - Zhipeng Bai
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China;
| | - Xinyu Han
- Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming 650500, China;
- Correspondence: ; Tel.: +86-150-8715-0201
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Sahu LK, Tripathi N, Gupta M, Singh V, Yadav R, Patel K. Impact of COVID-19 Pandemic Lockdown in Ambient Concentrations of Aromatic Volatile Organic Compounds in a Metropolitan City of Western India. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2022; 127:e2022JD036628. [PMID: 35602912 PMCID: PMC9111284 DOI: 10.1029/2022jd036628] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/06/2022] [Indexed: 06/15/2023]
Abstract
The real-time Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX) concentrations were measured in a metropolitan city of India during January to May of 2020 and 2014-2015-2018 to assess the impact of emission reduction during the COVID-19 lockdown. The total BTEX (∑BTEX) concentrations were 11.5 ± 9.0, 15.7 ± 16, 5.3 ± 5.0, 2.9 ± 2.0, and 0.93 ± 1.2 ppbv in January-May 2020, respectively. The evening rush hour peaks of BTEX during lockdown decreased by 4-5 times from the same period of years 2014-2015-2018. A significant decline in background concentrations suggests a regional-scale reduction in anthropogenic emissions. The contributions of ∑TEX compounds to ∑BTEX increased from 42% to 59% in winter to 64%-75% during the lockdown under hot summer conditions. While emission reductions dominated during the lockdown period, the meteorological and photochemical factors may also have contributed. Meteorological influence on actual observed BTEX data was removed by normalizing with ventilation coefficient (VC). The actual ambient air reductions of 85%-90% and VC-normalized reductions of 54%-88% of the BTEX concentrations during lockdown were estimated compared to those during the same period of 2014-2015-2018. The estimated changes using nighttime data, which take into account BTEX photooxidation removal, are ∼8% lower than the VC-normalized estimates using all data. These significant reductions in BTEX concentrations are consistent with the change in people's movement as inferred from mobility data during the lockdown. Although enforced, the significant decline in ambient BTEX levels during lockdown was a good change for the air quality. The study suggests a need for more effective science-based policies that consider local and regional factors.
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Affiliation(s)
- L. K. Sahu
- Physical Research Laboratory (PRL)AhmedabadIndia
| | | | - Mansi Gupta
- Physical Research Laboratory (PRL)AhmedabadIndia
- Indian Institute of Technology GandhinagarGandhinagarIndia
| | - Vikas Singh
- National Atmospheric Research Laboratory (NARL)GadankiIndia
| | - Ravi Yadav
- Indian Institute of Tropical Meteorology (IITM)PuneIndia
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Zhang G, Hu R, Xie P, Lou S, Wang F, Wang Y, Qin M, Li X, Liu X, Wang Y, Liu W. Observation and simulation of HOx radicals in an urban area in Shanghai, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 810:152275. [PMID: 34902401 DOI: 10.1016/j.scitotenv.2021.152275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/01/2021] [Accepted: 12/05/2021] [Indexed: 05/25/2023]
Abstract
A continuous wintertime observation of ambient OH and HO2 radicals was first carried out in Shanghai, in 2019. This effort coincided with the second China International Import Expo (CIIE), during which strict emission controls were implemented in Shanghai, resulting in an average PM2.5 concentration of less than 35 μg/m3. The self-developed instrument based on the laser-induced fluorescence (LIF) technique reported that the average OH radical concentration at noontime (11:00-13:00) was 2.7 × 106 cm-3, while the HO2 concentration was 0.8 × 108 cm-3. A chemical box model utilizing the Regional Atmospheric Chemical Mechanism 2 (RACM2), which is used to simulate pollutant reactions and other processes in the troposphere and which incorporates the Leuven isoprene mechanism (LIM1), reproduced the OH concentrations on most days. The HO2 concentration was underestimated, and the observed-to-modelled ratio demonstrated poor performance by the model, especially during the elevated photochemistry period. Missing primary peroxy radical sources or unknown behaviors of RO2 for high-NOx regimes are possible reasons for the discrepancy. The daytime ROx production was controlled by various sources. HONO photolysis accounted for more than one half (0.83 ppb/h), and the contribution from formaldehyde, OVOCs and ozone photolysis was relatively similar. Active oxidation paths accelerated the rapid ozone increase in winter. The average ozone production rate was 15.1 ppb/h, which is comparable to that of a Beijing suburb (10 ppb/h for the 'BEST-ONE') but much lower than that of Beijing's center (39 ppb/h in 'PKU' and 71 ppb/h in 'APHH') in wintertime. Cumulative local ozone based on observed peroxy radicals was five times higher than the value simulated by the current model due to the underprediction of HO2 and RO2 under the high-NOx regime. This analysis provides crucial information for subsequent pollution control policies in Shanghai.
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Affiliation(s)
- Guoxian Zhang
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China; University of Science and Technology of China, Hefei, China
| | - Renzhi Hu
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China.
| | - Pinhua Xie
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China; University of Science and Technology of China, Hefei, China; College of Resources and Environment, University of Chinese Academy of Science, Beijing, China; CAS Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.
| | - Shengrong Lou
- State Environmental Protection Key Laboratory of the Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai, China
| | - Fengyang Wang
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China
| | - Yihui Wang
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China
| | - Min Qin
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China
| | - Xin Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China
| | - Xiaoyan Liu
- College of Pharmacy, Anhui Medical University, Hefei, China
| | - Yue Wang
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China
| | - Wenqing Liu
- Key Laboratory of Environment Optics and Technology, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, China
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29
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Wang S, Sun F, Wang X, Wei Y, Li L, Wang W, Zhang R, Ding Z, Dang J, Xu F, Wang W, Huo X, Zhang Q, Wang Q. Atmospheric oxidation of dichlorodiphenyltrichloroethane (DDT) initiated by OH and NO3 radicals: A quantum chemical investigation. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2021.139225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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30
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Liu P, Ye C, Zhang C, He G, Xue C, Liu J, Liu C, Zhang Y, Song Y, Li X, Wang X, Chen J, He H, Herrmann H, Mu Y. Photochemical Aging of Atmospheric Fine Particles as a Potential Source for Gas-Phase Hydrogen Peroxide. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:15063-15071. [PMID: 34705458 DOI: 10.1021/acs.est.1c04453] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Atmospheric hydrogen peroxide (H2O2), as an important oxidant, plays a key role in atmospheric sulfate formation, affecting the global radiation budget and causing acid rain deposition. The disproportionation reactions of hydroperoxyl radicals (HO2) in both gas and aqueous phases have long been considered as dominant sources for atmospheric H2O2. However, these known sources cannot explain the significant formation of H2O2 in polluted areas under the conditions of high NO levels and low ambient relative humidity (RH). Here, we show that under relatively dry conditions during daytime, atmospheric fine particles directly produce abundant gas-phase H2O2. The formation of H2O2 is verified to be by a reaction between the particle surface -OH group and HO2 radicals formed by photooxidation of chromophoric dissolved organic matters (CDOMs), which is slightly influenced by the presence of high NO levels but remarkably accelerated by water vapor and O2. In contrast to aqueous-phase chemistry, transition metal ions (TMIs) are found to significantly suppress H2O2 formation from the atmospheric fine particles. The H2O2 formed from relatively dry particles can be directly involved in in situ SO2 oxidation, leading to sulfate formation. As CDOMs are ubiquitous in atmospheric fine particles, their daytime photochemistry is expected to play important roles in formation of H2O2 and sulfate worldwide.
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Affiliation(s)
- Pengfei Liu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Can Ye
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Chenglong Zhang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guangzhi He
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chaoyang Xue
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Junfeng Liu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chengtang Liu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yuanyuan Zhang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yifei Song
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuran Li
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinming Wang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jianmin Chen
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Institute of Atmospheric Sciences, Fudan University, Shanghai 200438, China
| | - Hong He
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hartmut Herrmann
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Institute of Atmospheric Sciences, Fudan University, Shanghai 200438, China
- Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), 04318 Leipzig, Germany
- Environmental Research Institute, Shandong University, Jinan 250100, China
| | - Yujing Mu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Zhang S, Sarwar G, Xing J, Chu B, Xue C, Sarav A, Ding D, Zheng H, Mu Y, Duan F, Ma T, He H. Improving the representation of HONO chemistry in CMAQ and examining its impact on haze over China. ATMOSPHERIC CHEMISTRY AND PHYSICS 2021; 21:15809-15826. [PMID: 34804135 PMCID: PMC8597575 DOI: 10.5194/acp-21-15809-2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We compare Community Multiscale Air Quality (CMAQ) model predictions with measured nitrous acid (HONO) concentrations in Beijing, China for December 2015. The model with the existing HONO chemistry in CMAQ severely under-estimates the observed HONO concentrations with a normalized mean bias of -97%. We revise the HONO chemistry in the model by implementing six additional heterogeneous reactions in the model: reaction of nitrogen dioxide (NO2) on ground surfaces, reaction of NO2 on aerosol surfaces, reaction of NO2 on soot surfaces, photolysis of aerosol nitrate, nitric acid displacement reaction, and hydrochloric acid displacement reaction. The model with the revised chemistry substantially increases HONO predictions and improves the comparison with observed data with a normalized mean bias of -5%. The photolysis of HONO enhances day-time hydroxyl radical by almost a factor of two. The enhanced hydroxyl radical concentrations compare favourably with observed data and produce additional sulfate via the reaction with sulfur dioxide, aerosol nitrate via the reaction with nitrogen dioxide, and secondary organic aerosols via the reactions with volatile organic compounds. The additional sulfate stemming from revised HONO chemistry improves the comparison with observed concentration; however, it does not close the gap between model prediction and the observation during polluted days.
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Affiliation(s)
- Shuping Zhang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Golam Sarwar
- Center for Environmental Measurement and Modeling, U.S. Environmental Protection Agency, 109 T.W. Alexander Drive, Research Triangle Park, NC, 27711, USA
| | - Jia Xing
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Biwu Chu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Chaoyang Xue
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Arunachalam Sarav
- Institute for the Environment, The University of North Carolina at Chapel Hill, 100 Eurpoa Drive, Chapel Hill, NC 27514, USA
| | - Dian Ding
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Haotian Zheng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yujing Mu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Fengkui Duan
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Tao Ma
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Hong He
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
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Chen Y, Tong S, Li W, Liu Y, Tan F, Ge M, Xie X, Sun J. Photocatalytic Oxidation of SO 2 by TiO 2: Aerosol Formation and the Key Role of Gaseous Reactive Oxygen Species. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:9784-9793. [PMID: 34232022 DOI: 10.1021/acs.est.1c01608] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Photocatalytic materials are proved to effectively eliminate gaseous pollutants and are widely used in the environment. However, as one of the rare experiments focusing on their influence on secondary aerosol formation generated in the gas phase (SAg), our study demonstrated the high-yield SAg formation in the photocatalysis process. In this study, the photodegradation of SO2 by TiO2 under various relative humidity (RH) conditions was deeply explored with multiple methods. Unexpectedly, H2SO4 aerosols (SAg-H2SO4) in yields of 10.10-32.64% were observed under the studied RH conditions for the first time. Gaseous •OH and H2O2 generated from the oxidation of H2O and reduction of O2 by TiO2 were directly detected in the photocatalysis process, and they were identified as the determining factor for SAg-H2SO4 formation. The formation of SAg-H2SO4 was also influenced by RH, the heterogeneous reaction of SO2, and the uptake of H2SO4. The role of the released gaseous •OH and H2O2 on atmospheric chemistry was proved to be unignorable by adopting the obtained parameters into the real environment. These findings provided direct experimental evidence of secondary pollution in the photocatalysis process and are of great significance to the field of atmospheric environment and photocatalytic materials.
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Affiliation(s)
- Yi Chen
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Shengrui Tong
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Weiran Li
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Yanping Liu
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Fang Tan
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Maofa Ge
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Xiaofeng Xie
- Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
| | - Jing Sun
- Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
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Allani A, Bedjanian Y, Papanastasiou DK, Romanias MN. Reaction Rate Coefficient of OH Radicals with d 9-Butanol as a Function of Temperature. ACS OMEGA 2021; 6:18123-18134. [PMID: 34308045 PMCID: PMC8296604 DOI: 10.1021/acsomega.1c01942] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 06/02/2021] [Indexed: 06/13/2023]
Abstract
d 9-Butanol or 1-butan-d 9-ol (D9B) is often used as an OH radical tracer in atmospheric chemistry studies to determine OH exposure, a useful universal metric that describes the extent of OH radical oxidation chemistry. Despite its frequent application, there is only one study that reports the rate coefficient of D9B with OH radicals, k 1(295 K), which limits its usefulness as an OH tracer for studying processes at temperatures lower or higher than room temperature. In this study, two complementary experimental techniques were used to measure the rate coefficient of D9B with OH radicals, k 1(T), at temperatures between 240 and 750 K and at pressures within 2-760 Torr. A thermally regulated atmospheric simulation chamber was used to determine k 1(T) in the temperature range of 263-353 K and at atmospheric pressure using the relative rate method. A low-pressure (2-10 Torr) discharge flow tube reactor coupled with a mass spectrometer was used to measure k 1(T) at temperatures within 240-750 K, using both the absolute and relative rate methods. The agreement between the two experimental aproaches followed in this study was very good, within 6%, in the overlapping temperature range, and k 1(295 ± 3 K) was 3.42 ± 0.26 × 10-12 cm3 molecule-1 s-1, where the quoted error is the overall uncertainty of the measurements. The temperature dependence of the rate coefficient is well described by the modified Arrhenius expression, k 1 = (1.57 ± 0.88) × 10-14 × (T/293)4.60±0.4 × exp(1606 ± 164/T) cm3 molecule-1 s-1 in the range of 240-750 K, where the quoted error represents the 2σ standard deviation of the fit. The results of the current study enable an accurate estimation of OH exposure in atmospheric simulation experiments and expand the applicability of D9B as an OH radical tracer at temperatures other than room temperature.
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Affiliation(s)
- Amira Allani
- IMT
Lille Douai, Univ. Lille, SAGE, Lille F-59000, France
| | - Yuri Bedjanian
- Institut
de Combustion, Aérothermique, Réactivité et Environnement
(ICARE), CNRS, Orléans Cedex
2 45071, France
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Chemical insights into the atmospheric oxidation of thiophene by hydroperoxyl radical. Sci Rep 2021; 11:13049. [PMID: 34158534 PMCID: PMC8219665 DOI: 10.1038/s41598-021-92221-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 06/08/2021] [Indexed: 11/08/2022] Open
Abstract
The reaction mechanisms and kinetics of thiophene oxidation reactions initiated by hydroperoxyl radical, and decomposition of the related intermediates and complexes, have been considered herein by using high-level DFT and ab initio calculations. The main energetic parameters of all stationary points of the suggested potential energy surfaces have been computed at the BD(T) and CCSD(T) methods, based on the geometries optimized at the B3LYP/6-311 + g(d,p) level of theory. Rate constants of bimolecular reactions (high-pressure limit rate constants) at temperatures from 300 to 3000 K for the first steps of the title reaction have been obtained through the conventional transition state theory (TST), while the pressure dependent rate constants and the rate constants of the second and other steps have been calculated employing the Rice-Ramsperger-Kassel-Marcus/Master equation (RRKM/ME). The results show that the rate constants of addition to α and β carbons have positive temperature dependence and negative pressure dependence. It is found that the additions of HO2 to the α and β carbons of thiophene in the initial steps of the title reaction are the most favored pathways. Also, the addition to the sulfur atom has a minor contribution. But, all efforts for simulating hydrogen abstraction reactions have been unsuccessful. In this complex oxidation reaction, about 12 different products are obtained, including important isomers such as thiophene-epoxide, thiophene-ol, thiophene-oxide, oxathiane, and thiophenone. The calculated total rate constants for generation of all minimum stationary points show that the addition reactions to the α and β carbons are the fastest among all at temperatures below 1000 K, while the proposed multi-step parallel reactions are more competitive at temperatures above 1200 K. Furthermore, important inter-and intra-molecular interactions for some species have been investigated by two well-known quantum chemistry method, the NBO and AIM analyses. Thermochemical properties such as free energy, enthalpy, internal energy, and entropy for thiophene and hydroperoxyl radical and related species in the simulated reactions have been predicted using a combination of the B3LYP and BD(T) methods.
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Antonov IO, Stollenwerk PR, Venkataramanababu S, de Lima Batista AP, de Oliveira-Filho AGS, Odom BC. Precisely spun super rotors. Nat Commun 2021; 12:2201. [PMID: 33850116 PMCID: PMC8044131 DOI: 10.1038/s41467-021-22342-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 03/03/2021] [Indexed: 11/09/2022] Open
Abstract
Improved optical control of molecular quantum states promises new applications including chemistry in the quantum regime, precision tests of fundamental physics, and quantum information processing. While much work has sought to prepare ground state molecules, excited states are also of interest. Here, we demonstrate a broadband optical approach to pump trapped SiO+ molecules into pure super rotor ensembles maintained for many minutes. Super rotor ensembles pumped up to rotational state N = 67, corresponding to the peak of a 9400 K distribution, had a narrow N spread comparable to that of a few-kelvin sample, and were used for spectroscopy of the previously unobserved C2Π state. Significant centrifugal distortion of super rotors pumped up to N = 230 allowed probing electronic structure of SiO+ stretched far from its equilibrium bond length. Optical pulses can be useful to create and control molecules in higher quantum states. Here the authors use optical pumping to create rotationally excited states of SiO+ molecular ion into super rotor ensemble.
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Affiliation(s)
- Ivan O Antonov
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, USA
| | | | | | - Ana P de Lima Batista
- Departamento de Química, Laboratório Computacional de Espectroscopia e Cinética, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto-SP, Brazil
| | - Antonio G S de Oliveira-Filho
- Departamento de Química, Laboratório Computacional de Espectroscopia e Cinética, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto-SP, Brazil
| | - Brian C Odom
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, USA. .,Applied Physics program, Northwestern University, Evanston, IL, USA.
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Church JR, Vaida V, Skodje RT. Kinetic Study of Gas-Phase Reactions of Pyruvic Acid with HO 2. J Phys Chem A 2021; 125:2232-2242. [PMID: 33705144 DOI: 10.1021/acs.jpca.0c10475] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Gas-phase reactions between pyruvic acid (PA) and HO2 radicals were examined using ab initio quantum chemistry and transition state theory. The rate coefficients were determined over a temperature range of 200-400 K including tunneling contributions. Six potential reaction pathways were identified. The two hydrogen abstraction reactions yielding the H2O2 product were found to have high barriers. The HO2 radical was also found to have a catalytic effect on the intramolecular hydrogen transfer reactions occurring by three distinct routes. These hydrogen-shift reactions are very interesting mechanistically although they are highly endothermic. The only reaction that contributes significantly to the consumption of PA is a multistep pathway involving a peroxy-radical intermediate, PA + HO2 → CH3COOH + OH + CO2. This exothermic process has potential atmospheric relevance because it produces an OH radical as a product. Atmospheric models currently have difficulty predicting accurate OH concentrations for certain atmospheric conditions, such as environments free of NOx and the nocturnal boundary layer. Reactions of this sort, although not necessary with PA, may account for a portion of this deficit. The present study helps settle the issue of the relative roles of reaction and photolysis in consumption of PA in the troposphere.
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Affiliation(s)
- Jonathan R Church
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Veronica Vaida
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Rex T Skodje
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
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Wang G, Iradukunda Y, Shi G, Sanga P, Niu X, Wu Z. Hydroxyl, hydroperoxyl free radicals determination methods in atmosphere and troposphere. J Environ Sci (China) 2021; 99:324-335. [PMID: 33183711 DOI: 10.1016/j.jes.2020.06.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 06/15/2020] [Accepted: 06/30/2020] [Indexed: 06/11/2023]
Abstract
The hydroxyl radical (•OH) has a crucial function in the oxidation and removal of many atmospheric compounds that are harmful to health. Nevertheless, high reactivity, low atmospheric abundance, determination of hydroxyl, and hydroperoxyl radical's quantity is very difficult. In the atmosphere and troposphere, hydroperoxyl radicals (HO2) are closely demanded in the chemical oxidation of the troposphere. But advances in technology have allowed researchers to improve the determination methods on the research of free radicals through some spectroscopic techniques. So far, several methods such as laser-induced fluorescence (LIF), high-performance liquid chromatography (HPLC), and chemical ionization mass spectroscopy have been identified and mostly used in determining the quantity of hydroxyl and hydroperoxyl radicals. In this systematic review, we have advised the use of scavenger as an advance for further researchers to circumvent some of these problems caused by free radicals. The primary goal of this review is to deepen our understanding of the functions of the most critical free radical (•OH, HO2) and also understand the currently used methods to quantify them in the atmosphere and troposphere.
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Affiliation(s)
- Guoying Wang
- School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou 730050, China.
| | - Yves Iradukunda
- School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou 730050, China
| | - Gaofeng Shi
- School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou 730050, China
| | - Pascaline Sanga
- School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou 730050, China
| | - Xiuli Niu
- Gansu Food Inspection and Research Institute, Lanzhou 730050, China
| | - Zhijun Wu
- State Key Joint Laboratory of Environment Simulation and Pollution Control (Peking University), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
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Zhu M, Lu J, Hu Y, Liu Y, Hu S, Zhu C. Photochemical reactions between 1,4-benzoquinone and O 2•. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:31289-31299. [PMID: 32488712 DOI: 10.1007/s11356-020-09422-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/22/2020] [Indexed: 06/11/2023]
Abstract
The superoxide anion radical (O2•-) is one of the most predominant reactive oxygen species (ROS), which is also involved in diverse chemical and biological processes. In this study, O2•- was generated by irradiating riboflavin in an O2-saturated solution using an ultraviolet lamp (λem = 365 nm) as the light source. The photochemical reduction of 1,4-benzoquinone (p-BQ) by O2•- was explored by 355-nm laser flash photolysis (LFP) and 365-nm UV light steady irradiation. The results showed that the photodecomposition efficiency of p-BQ was influenced by the riboflavin concentration, p-BQ initial concentration, and pH values. The superoxide anion radical originating from riboflavin photolysis served as a reductant to react with p-BQ, forming reduced BQ radicals (BQ•-) with a second-order rate constant of 1.1 × 109 L mol-1 s-1. The main product of the photochemical reaction between p-BQ and O2•- was hydroquinone (H2Q). The present work suggests that the reaction with O2•- is a potential transformation pathway of 1, 4-benzoquinone in atmospheric aqueous environments.
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Affiliation(s)
- Mengyu Zhu
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, People's Republic of China
- Institute of Atmospheric Environment & Pollution Control, Hefei University of Technology, Hefei, 230009, People's Republic of China
| | - Jun Lu
- Center of Analysis & Measurement, Hefei University of Technology, Hefei, 230009, People's Republic of China
| | - Yadong Hu
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, People's Republic of China
- Institute of Atmospheric Environment & Pollution Control, Hefei University of Technology, Hefei, 230009, People's Republic of China
| | - Ying Liu
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, People's Republic of China
- Institute of Atmospheric Environment & Pollution Control, Hefei University of Technology, Hefei, 230009, People's Republic of China
| | - Shuheng Hu
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, People's Republic of China
- Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei, 230009, People's Republic of China
| | - Chengzhu Zhu
- School of Resource and Environmental Engineering, Hefei University of Technology, Hefei, 230009, People's Republic of China.
- Institute of Atmospheric Environment & Pollution Control, Hefei University of Technology, Hefei, 230009, People's Republic of China.
- Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei, 230009, People's Republic of China.
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40
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Larsen G, Babineau D. An Evaluation of the Global Effects of Tritium Emissions from Nuclear Fusion Power. FUSION ENGINEERING AND DESIGN 2020. [DOI: 10.1016/j.fusengdes.2020.111690] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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41
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Gao J, Zuo P, Zhu T, Gong Q, Jiang H. Study of the Formation Dynamics of OH from the Photolysis of O 3 by Ultrashort Laser Pulses. J Phys Chem Lett 2020; 11:6482-6486. [PMID: 32692574 DOI: 10.1021/acs.jpclett.0c01770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We report the first experimental detection of the laser-induced formation dynamics of OH under normal pressure, which was observed using the pump-probe scheme with two 250 fs laser pulses at 282.2 nm. The first laser photolyzes O3 to form OH, and the second laser excites OH to induce fluorescence at 308 nm. The fluorescence cannot be detected with a single beam because the femtosecond pulses have already passed through the sample before the formation of OH from their own photolysis. A photochemical dynamic model was built, and the experimental results are in good agreement with the model. This method can also be used for other OH-related dynamic measurements, which can effectively avoid laser-generated interference from the photolysis of O3.
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Affiliation(s)
- Jingsong Gao
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Peng Zuo
- BIC-ESAT and SKL-ESPC, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Tong Zhu
- BIC-ESAT and SKL-ESPC, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Qihuang Gong
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Hongbing Jiang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
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42
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Baek YS, Kim K, Saiz-Lopez A, Min DW, Kim B, Choi W, Choi CH. Entangled iodine and hydrogen peroxide formation in ice. Phys Chem Chem Phys 2020; 22:16532-16535. [PMID: 32691035 DOI: 10.1039/d0cp02966a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ice-core records show that anthropogenic pollution has increased the global atmospheric concentrations of hydrogen peroxide and iodine since the mid-20th century. Here, for the first time, we demonstrate a highly efficient mechanism that synergistically produces them in icy water conditions. This reaction is aided by a key intermediate IO2H, formed by an I- ion with a dissolved O2 in acidic icy water, which produces both I as well as O2H radicals. I recombines with I- to produce I2- at a diffusion-limited rate, followed by formation of I3- through disproportionation, while O2H yields H2O2 with I- and a proton dissolved in icy water.
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Affiliation(s)
- Yong Su Baek
- Department of Chemistry and Green-Nano Materials Research Center, College of Natural Sciences, Kyungpook National University, Sangyeok, Bukgu, Daegu 41566, South Korea.
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43
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Water Catalysis of the Reaction of Methanol with OH Radical in the Atmosphere is Negligible. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202001065] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Wu J, Gao LG, Varga Z, Xu X, Ren W, Truhlar DG. Water Catalysis of the Reaction of Methanol with OH Radical in the Atmosphere is Negligible. Angew Chem Int Ed Engl 2020; 59:10826-10830. [DOI: 10.1002/anie.202001065] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/23/2020] [Indexed: 11/07/2022]
Affiliation(s)
- Junjun Wu
- Department of Mechanical and Automation Engineering & Shenzhen Research Institute The Chinese University of Hong Kong New Territories Hong Kong SAR China
| | - Lu Gem Gao
- Center for Combustion Energy Department of Energy and Power Engineering Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University Beijing China
| | - Zoltan Varga
- Department of Chemistry, Chemical Theory Center and Supercomputing Institute University of Minnesota Minneapolis USA
| | - Xuefei Xu
- Center for Combustion Energy Department of Energy and Power Engineering Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University Beijing China
| | - Wei Ren
- Department of Mechanical and Automation Engineering & Shenzhen Research Institute The Chinese University of Hong Kong New Territories Hong Kong SAR China
| | - Donald G. Truhlar
- Department of Chemistry, Chemical Theory Center and Supercomputing Institute University of Minnesota Minneapolis USA
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Earla A, Walter ED, Braslau R. Synthesis and spin trapping properties of polystyrene supported trifluoromethylated cyclic nitrones. Free Radic Res 2019; 53:1084-1100. [PMID: 31739700 PMCID: PMC10805450 DOI: 10.1080/10715762.2019.1683171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 10/08/2019] [Accepted: 10/10/2019] [Indexed: 01/21/2023]
Abstract
Polystyrene supported fluorinated cyclic nitrone spin-traps: Resin-2-HFDMPO (2-hydroxymethyl-2-methyl-5-(trifluoromethyl)-3,4-dihydro-2H-pyrrole-1-oxide) and Resin-2-PFDMPO (2-(3-hydroxypropyl)-2-methyl-5-(trifluoromethyl)-3,4-dihydro-2H-pyrrole 1-oxide) containing a trifluoromethyl pyrroline-N-oxide core were developed to detect free radicals under flow conditions. A continuous flow EPR technique was used to evaluate the spin trapping properties of these tethered nitrones. While both resins trapped radicals, polymer supported nitrone Resin-2-PFDMPO with a longer and more flexible linker showed a more information rich spectrum than Resin-2-HFDMPO.
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Affiliation(s)
- Aruna Earla
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
| | - Eric D. Walter
- Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Rebecca Braslau
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
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Lu K, Guo S, Tan Z, Wang H, Shang D, Liu Y, Li X, Wu Z, Hu M, Zhang Y. Exploring atmospheric free-radical chemistry in China: the self-cleansing capacity and the formation of secondary air pollution. Natl Sci Rev 2019; 6:579-594. [PMID: 34691906 PMCID: PMC8291643 DOI: 10.1093/nsr/nwy073] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/12/2018] [Accepted: 07/18/2018] [Indexed: 11/14/2022] Open
Abstract
Since 1971, it has been known that the atmospheric free radicals play a pivotal role in maintaining the oxidizing power of the troposphere. The existence of the oxidizing power is an important feature of the troposphere to remove primary air pollutants emitted from human beings as well as those from the biosphere. Nevertheless, serious secondary air-pollution incidents can take place due to fast oxidation of the primary pollutants. Elucidating the atmospheric free-radical chemistry is a demanding task in the field of atmospheric chemistry worldwide, which includes two kinds of work: first, the setup of reliable radical detection systems; second, integrated field studies that enable closure studies on the sources and sinks of targeted radicals such as OH and NO3. In this review, we try to review the Chinese efforts to explore the atmospheric free-radical chemistry in such chemical complex environments and the possible link of this fast gas-phase oxidation with the fast formation of secondary air pollution in the city-cluster areas in China.
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Affiliation(s)
- Keding Lu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Song Guo
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Zhaofeng Tan
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Haichao Wang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Dongjie Shang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yuhan Liu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xin Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Zhijun Wu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Min Hu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yuanhang Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
- CAS Center for Excellence in Regional Atmospheric Environment, Chinese Academy of Sciences, Xiamen 361021, China
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DeGregorio N, Iyengar SS. Adaptive Dimensional Decoupling for Compression of Quantum Nuclear Wave Functions and Efficient Potential Energy Surface Representations through Tensor Network Decomposition. J Chem Theory Comput 2019; 15:2780-2796. [DOI: 10.1021/acs.jctc.8b01113] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nicole DeGregorio
- Department of Chemistry and Department of Physics, Indiana University, 800 E. Kirkwood Ave, Bloomington, Indiana 47405, United States
| | - Srinivasan S. Iyengar
- Department of Chemistry and Department of Physics, Indiana University, 800 E. Kirkwood Ave, Bloomington, Indiana 47405, United States
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del Mazo-Sevillano P, Aguado A, Jiménez E, Suleimanov YV, Roncero O. Quantum Roaming in the Complex-Forming Mechanism of the Reactions of OH with Formaldehyde and Methanol at Low Temperature and Zero Pressure: A Ring Polymer Molecular Dynamics Approach. J Phys Chem Lett 2019; 10:1900-1907. [PMID: 30939028 PMCID: PMC6534501 DOI: 10.1021/acs.jpclett.9b00555] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The quantum dynamics of the title reactions are studied using the ring polymer molecular dynamics (RPMD) method from 20 to 1200 K using recently proposed full dimensional potential energy surfaces which include long-range dipole-dipole interactions. A V-shaped dependence of the reaction rate constants is found with a minimum at 200-300 K, in rather good agreement with the current experimental data. For temperatures above 300 K the reaction proceeds following a direct H-abstraction mechanism. However, below 100 K the reaction proceeds via organic-molecule···OH collision complexes, with very long lifetimes, longer than 10-7 s, associated with quantum roaming arising from the inclusion of quantum effects by the use of RPMD. The long lifetimes of these complexes are comparable to the time scale of the tunnelling to form reaction products. These complexes are formed at zero pressure because of quantum effects and not only at high pressure as suggested by transition state theory (TST) calculations for OH + methanol and other OH reactions. The zero-pressure rate constants reproduce quite well measured ones below 200 K, and this agreement opens the question of how important the pressure effects on the reaction rate constants are, as implied in TST-like formalisms. The zero-pressure mechanism is applicable only to very low gas density environments, such as the interstellar medium, which are not repeatable by experiments.
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Affiliation(s)
- Pablo del Mazo-Sevillano
- Unidad Asociada UAM-CSIC, Departamento de Química Física Aplicada, Facultad de Ciencias M-14, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Alfredo Aguado
- Unidad Asociada UAM-CSIC, Departamento de Química Física Aplicada, Facultad de Ciencias M-14, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Elena Jiménez
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla La Mancha, Avda. Camilo José Cela 1B, 13071 Ciudad Real, Spain
- Instituto de Investigación en Combustión y Contaminación Atmosférica, Universidad de Castilla La Mancha, Camino de Moledores s/n, 13071 Ciudad Real, Spain
| | - Yury V. Suleimanov
- Computation-based Science and Technology Research Center, Cyprus Institute, 20 Kavafi Str., Nicosia 2121, Cyprus
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139, United States
| | - Octavio Roncero
- Instituto de Física Fundamental (IFF-CSIC), C.S.I.C., Serrano 123, 28006 Madrid, Spain
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Wang F, Hu R, Chen H, Xie P, Wang Y, Li Z, Jin H, Liu J, Liu W. Development of a field system for measurement of tropospheric OH radical using laser-induced fluorescence technique. OPTICS EXPRESS 2019; 27:A419-A435. [PMID: 31052893 DOI: 10.1364/oe.27.00a419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 03/05/2019] [Indexed: 06/09/2023]
Abstract
A ground-based system for measuring tropospheric OH radical based on laser-induced fluorescence (AIOFM-LIF) was developed in this work. In this system, ambient air is expanded through a 0.4 mm nozzle to low pressure in a detection chamber, where OH radical is irradiated by the 308 nm laser pulse at a repetition rate of 8.5 kHz. Then, the resultant fluorescence corresponding to the A2Σ+(υ'=0)←X2Πi(ν''=0) transition at 308 nm is detected using gated photon counting. The AIOFM-LIF system was integrated into a mobile observing platform for the field observation following the series of laboratory characterization. A portable standard OH radical source by water photolysis-ozone actinometry was established and optimized for accurate system calibration. The factors affecting the system sensitivity were quantified. It was shown that the ultimate system sensitivity is 9.9 × 10-8 cps (molecules cm-3)-1 mw-1; the minimum detection limits are (1.84 ± 0.26) × 105 cm-3 and (3.69 ± 0.52) × 105 cm-3 at night and noon, respectively; and the whole error of AIOFM-LIF system is about 16%. Then, the system was deployed in Shenzhen, China, during the "A comprehensive STudy of the Ozone foRmation Mechanism in Shenzhen" (STORM) campaign. Valid OH radical concentrations for 31 days were obtained, and the peak of the daily average concentration was 6.6 × 106 cm-3 around 12:00. And a high correlation (R2 = 0.77) between OH and j(O1D) was also observed in this field campaign. The relationship between OH concentration and NOx was attentively discussed. The deployment of AIOFM-LIF system in STORM campaign has demonstrated its capability of measuring tropospheric OH radical with high sensitivity and accuracy in a polluted environment.
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Farmer DK. Analytical Challenges and Opportunities For Indoor Air Chemistry Field Studies. Anal Chem 2019; 91:3761-3767. [DOI: 10.1021/acs.analchem.9b00277] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Delphine K. Farmer
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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