1
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Trew AJ, Early C, Ellis R, Nash J, Pemberton K, Tyler P, Harrison TG, Shallcross DE. Chemical Science Research, Elementary School Children and Their Teachers Are More Closely Related than You May Imagine: The "I Bet You Did Not Know" Project. J Chem Educ 2024; 101:337-343. [PMID: 38370575 PMCID: PMC10867834 DOI: 10.1021/acs.jchemed.3c00233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 02/20/2024]
Abstract
Topics associated with the chemical sciences form a significant part of the curriculum in science at the primary school level in the U.K. In this methodology paper, we demonstrate how a wide range of research articles associated with the chemical sciences can be disseminated to an elementary school audience and how children can carry out investigations associated with cutting-edge research in the classroom. We discuss how the Primary Science Teaching Trust's (PSTT's) "I bet you did not know" (IBYDK) articles and their accompanying Teacher Guides benefit children, primary (elementary) school teachers, and other stakeholders including the researchers themselves. We define three types of research articles; ones describing how children can reproduce the research themselves without much adaptation, others where children can mirror the research using similar methods, and some where an analogy can be used to explain the research. We provide exemplars of each type and some preliminary feedback on articles written.
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Affiliation(s)
- Alison J. Trew
- Primary
Science Teaching Trust, 12 Whiteladies Road, Bristol, BS8 1PD, U.K.
| | - Craig Early
- Primary
Science Teaching Trust, 12 Whiteladies Road, Bristol, BS8 1PD, U.K.
| | - Rebecca Ellis
- Primary
Science Teaching Trust, 12 Whiteladies Road, Bristol, BS8 1PD, U.K.
| | - Julia Nash
- Primary
Science Teaching Trust, 12 Whiteladies Road, Bristol, BS8 1PD, U.K.
| | | | - Paul Tyler
- Primary
Science Teaching Trust, 12 Whiteladies Road, Bristol, BS8 1PD, U.K.
| | - Timothy G. Harrison
- School
of Chemistry, Cantock’s Close, University
of Bristol, Bristol, BS8 1TS, U.K.
| | - Dudley E. Shallcross
- School
of Chemistry, Cantock’s Close, University
of Bristol, Bristol, BS8 1TS, U.K.
- Department
of Chemistry, University of the Western
Cape, Robert Sobukwe
Road, Bellville, 7535, South Africa
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2
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McGillen MR, Fried ZTP, Khan MAH, Kuwata KT, Martin CM, O’Doherty S, Pecere F, Shallcross DE, Stanley KM, Zhang K. Ozonolysis can produce long-lived greenhouse gases from commercial refrigerants. Proc Natl Acad Sci U S A 2023; 120:e2312714120. [PMID: 38079548 PMCID: PMC10742373 DOI: 10.1073/pnas.2312714120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 10/30/2023] [Indexed: 12/24/2023] Open
Abstract
Hydrofluoroolefins are being adopted as sustainable alternatives to long-lived fluorine- and chlorine-containing gases and are finding current or potential mass-market applications as refrigerants, among a myriad of other uses. Their olefinic bond affords relatively rapid reaction with hydroxyl radicals present in the atmosphere, leading to short lifetimes and proportionally small global warming potentials. However, this type of functionality also allows reaction with ozone, and whilst these reactions are slow, we show that the products of these reactions can be extremely long-lived. Our chamber measurements show that several industrially important hydrofluoroolefins produce CHF3 (fluoroform, HFC-23), a potent, long-lived greenhouse gas. When this process is accounted for in atmospheric chemical and transport modeling simulations, we find that the total radiative effect of certain compounds can be several times that of the direct radiative effect currently recommended by the World Meteorological Organization. Our supporting quantum chemical calculations indicate that a large range of exothermicity is exhibited in the initial stages of ozonolysis, which has a powerful influence on the CHF3 yield. Furthermore, we identify certain molecular configurations that preclude the formation of long-lived greenhouse gases. This demonstrates the importance of product quantification and ozonolysis kinetics in determining the overall environmental impact of hydrofluoroolefin emissions.
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Affiliation(s)
- Max R. McGillen
- CNRS-Orléans, Institut de Combustion Aérothermique Réactivité et Environnement, Orléans45071, France
| | - Zachary T. P. Fried
- Department of Chemistry, Massachusetts Institute of Technology, Boston, MA02139
| | - M. Anwar H. Khan
- School of Chemistry, University of Bristol, BristolBS8 1TS, United Kingdom
| | - Keith T. Kuwata
- Department of Chemistry, Macalester College, Saint Paul, MN55105
| | - Connor M. Martin
- Department of Chemistry, University of California, Irvine, CA92697
| | - Simon O’Doherty
- School of Chemistry, University of Bristol, BristolBS8 1TS, United Kingdom
| | - Francesco Pecere
- Department of Chemistry, The Pennsylvania State University, State College, PA16801
| | | | - Kieran M. Stanley
- School of Chemistry, University of Bristol, BristolBS8 1TS, United Kingdom
| | - Kexin Zhang
- Department of Chemistry, Northwestern University, Evanston, IL60208
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3
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Khan MA, Harrison TG, Wajrak M, Grimshaw M, Schofield KG, Trew AJ, Johal K, Morgan J, Shallcross KL, Sewry JD, Davies-Coleman MT, Shallcross DE. Flipping the Thinking on Equality, Diversity, and Inclusion. Why EDI Is Essential for the Development and Progression of the Chemical Sciences: A Case Study Approach. J Chem Educ 2023; 100:4279-4286. [PMID: 38028751 PMCID: PMC10653219 DOI: 10.1021/acs.jchemed.3c00364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 09/22/2023] [Indexed: 12/01/2023]
Abstract
All learners have a contribution to make to the development of the Chemical Sciences, be that in novel ways to teach, and their perspectives and contexts, but also in research, both in chemical education and the wider Chemical Sciences. Through four case studies, this paper explores interactions with diverse groups and how this has altered perspectives on both teaching and research. The case studies include work with visually impaired adults, a project bringing together First Peoples in Australia with academics to explore old ways (traditional science) and new ways (modern approaches), primary (elementary) school perspectives on teaching science, and a project in South Africa to connect university and township communities. Not only do these case studies demonstrate the immense value these diverse groups bring to our understanding about how to learn, but they also bring new perspectives on how to view and solve chemical problems.
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Affiliation(s)
- M. Anwar
H. Khan
- School
of Chemistry, Cantock’s Close, University
of Bristol, Bristol BS8 1TS, United
Kingdom
| | - Timothy G. Harrison
- School
of Chemistry, Cantock’s Close, University
of Bristol, Bristol BS8 1TS, United
Kingdom
| | - Magdalena Wajrak
- School
of Science, 270 Joondalup Drive, Edith Cowan
University, Perth, WA 6027, Australia
| | - Michele Grimshaw
- Primary
Science Teaching Trust, 12 Whiteladies Road, Bristol BS8 1PD, United Kingdom
| | - Kathy G. Schofield
- Primary
Science Teaching Trust, 12 Whiteladies Road, Bristol BS8 1PD, United Kingdom
| | - Alison J. Trew
- Primary
Science Teaching Trust, 12 Whiteladies Road, Bristol BS8 1PD, United Kingdom
| | - Kulvinder Johal
- Primary
Science Teaching Trust, 12 Whiteladies Road, Bristol BS8 1PD, United Kingdom
| | - Jeannette Morgan
- Primary
Science Teaching Trust, 12 Whiteladies Road, Bristol BS8 1PD, United Kingdom
| | - Karen. L. Shallcross
- School
of Chemistry, Cantock’s Close, University
of Bristol, Bristol BS8 1TS, United
Kingdom
| | - Joyce D. Sewry
- Department
of Chemistry, Rhodes University, Makhanda 6139, South Africa
| | - Michael T. Davies-Coleman
- Department
of Chemistry, Robert Sobukwe Drive, University
of Western Cape, Bellville 7535, South Africa
| | - Dudley E. Shallcross
- School
of Chemistry, Cantock’s Close, University
of Bristol, Bristol BS8 1TS, United
Kingdom
- Department
of Chemistry, Robert Sobukwe Drive, University
of Western Cape, Bellville 7535, South Africa
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4
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Wright MD, Buckley AJ, Matthews JC, Shallcross DE, Henshaw DL. Overhead AC powerlines and rain can alter the electric charge distribution on airborne particles - Implications for aerosol dispersion and lung deposition. Environ Res 2023; 228:115834. [PMID: 37037314 DOI: 10.1016/j.envres.2023.115834] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/21/2023] [Accepted: 04/01/2023] [Indexed: 05/16/2023]
Abstract
Corona ions from high voltage power lines (HVPL) can increase electrostatic charge on airborne pollutant particulates, possibly increasing received dose upon inhalation. To investigate the potential increased risk of childhood leukemia associated with residence near alternating current (AC) HVPL, we measured the particle charge state and atmospheric electricity parameters upwind, downwind and away from HVPL. Although we observed noticeable charge state alteration from background levels, most HVPL do not significantly increase charge magnitude. Particular HVPL types are shown to have most effect, increasing net charge to 15 times that at background. However, the magnitude of charge alteration during rainfall is comparable with the most extreme HVPL measurement. On current evidence, based on the current adult lung model, we suggest that although charge is sometimes enhanced to levels which may alter atmospheric particle dynamics, increased lung deposition is unlikely.
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Affiliation(s)
- Matthew D Wright
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, UK.
| | - Alison J Buckley
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, UK
| | - James C Matthews
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, UK
| | - Dudley E Shallcross
- Atmospheric Chemistry Research Group, School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
| | - Denis L Henshaw
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, UK
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5
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Luo PL, Chen IY, Khan MAH, Shallcross DE. Direct gas-phase formation of formic acid through reaction of Criegee intermediates with formaldehyde. Commun Chem 2023; 6:130. [PMID: 37349562 DOI: 10.1038/s42004-023-00933-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 06/14/2023] [Indexed: 06/24/2023] Open
Abstract
Ozonolysis of isoprene is considered to be an important source of formic acid (HCOOH), but its underlying reaction mechanisms related to HCOOH formation are poorly understood. Here, we report the kinetic and product studies of the reaction between the simplest Criegee intermediate (CH2OO) and formaldehyde (HCHO), both of which are the primary products formed in ozonolysis of isoprene. By utilizing time-resolved infrared laser spectrometry with the multifunctional dual-comb spectrometers, the rate coefficient kCH2OO+HCHO is determined to be (4.11 ± 0.25) × 10-12 cm3 molecule-1 s-1 at 296 K and a negative temperature dependence of the rate coefficient is observed and described by an Arrhenius expression with an activation energy of (-1.81 ± 0.04) kcal mol-1. Moreover, the branching ratios of the reaction products HCOOH + HCHO and CO + H2O + HCHO are explored. The yield of HCOOH is obtained to be 37-54% over the pressure (15-60 Torr) and temperature (283-313 K) ranges. The atmospheric implications of the reaction CH2OO + HCHO are also evaluated by incorporating these results into a global chemistry-transport model. In the upper troposphere, the percent loss of CH2OO by HCHO is found by up to 6% which can subsequently increase HCOOH mixing ratios by up to 2% during December-January-February months.
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Affiliation(s)
- Pei-Ling Luo
- 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
| | - M Anwar H Khan
- School of Chemistry, Cantock's Close, University of Bristol, Bristol, BS8 1TS, UK
| | - Dudley E Shallcross
- School of Chemistry, Cantock's Close, University of Bristol, Bristol, BS8 1TS, UK
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6
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Matthews E, Bannan TJ, Khan MAH, Shallcross DE, Stark H, Browne EC, Archibald AT, Mehra A, Bauguitte SJB, Reed C, Thamban NM, Wu H, Barker P, Lee J, Carpenter LJ, Yang M, Bell TG, Allen G, Jayne JT, Percival CJ, McFiggans G, Gallagher M, Coe H. Airborne observations over the North Atlantic Ocean reveal the importance of gas-phase urea in the atmosphere. Proc Natl Acad Sci U S A 2023; 120:e2218127120. [PMID: 37314935 DOI: 10.1073/pnas.2218127120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 04/20/2023] [Indexed: 06/16/2023] Open
Abstract
Reduced nitrogen (N) is central to global biogeochemistry, yet there are large uncertainties surrounding its sources and rate of cycling. Here, we present observations of gas-phase urea (CO(NH2)2) in the atmosphere from airborne high-resolution mass spectrometer measurements over the North Atlantic Ocean. We show that urea is ubiquitous in the lower troposphere in the summer, autumn, and winter but was not detected in the spring. The observations suggest that the ocean is the primary emission source, but further studies are required to understand the responsible mechanisms. Urea is also observed aloft due to long-range transport of biomass-burning plumes. These observations alongside global model simulations point to urea being an important, and currently unaccounted for, component of reduced-N to the remote marine atmosphere. Airborne transfer of urea between nutrient-rich and -poor parts of the ocean can occur readily and could impact ecosystems and oceanic uptake of carbon dioxide, with potentially important climate implications.
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Affiliation(s)
- Emily Matthews
- Department of Earth and Environmental Science, Centre for Atmospheric Science, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Thomas J Bannan
- Department of Earth and Environmental Science, Centre for Atmospheric Science, University of Manchester, Manchester M13 9PL, United Kingdom
| | - M Anwar H Khan
- Atmospheric Chemistry Research Group, School of Chemistry, Cantock's Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Dudley E Shallcross
- Atmospheric Chemistry Research Group, School of Chemistry, Cantock's Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Harald Stark
- Center for Aerosol and Cloud Chemistry, Aerodyne Research, Inc., Billerica, MA 01821
- Department of Chemistry, University of Colorado at Boulder, Boulder, CO 80309
- Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Boulder, CO 80309
| | - Eleanor C Browne
- Department of Chemistry, University of Colorado at Boulder, Boulder, CO 80309
- Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Boulder, CO 80309
| | - Alexander T Archibald
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
- National Centre for Atmospheric Science, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Archit Mehra
- Methods Analytics, London EC1N 8TS, United Kingdom
| | - Stéphane J-B Bauguitte
- Facility for Airborne Atmospheric Measurements Airborne Laboratory, Cranfield University, Cranfield MK43 0AL, United Kingdom
| | - Chris Reed
- Facility for Airborne Atmospheric Measurements Airborne Laboratory, Cranfield University, Cranfield MK43 0AL, United Kingdom
| | - Navaneeth M Thamban
- Department of Earth and Environmental Science, Centre for Atmospheric Science, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Huihui Wu
- Department of Earth and Environmental Science, Centre for Atmospheric Science, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Patrick Barker
- Department of Earth and Environmental Science, Centre for Atmospheric Science, University of Manchester, Manchester M13 9PL, United Kingdom
| | - James Lee
- Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York YO10 5DD, United Kingdom
- National Centre for Atmospheric Science, University of York, York YO10 5DD, United Kingdom
| | - Lucy J Carpenter
- Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York YO10 5DD, United Kingdom
| | - Mingxi Yang
- Plymouth Marine Laboratory, Plymouth PL1 3DH, United Kingdom
| | - Thomas G Bell
- Plymouth Marine Laboratory, Plymouth PL1 3DH, United Kingdom
| | - Grant Allen
- Department of Earth and Environmental Science, Centre for Atmospheric Science, University of Manchester, Manchester M13 9PL, United Kingdom
| | - John T Jayne
- Center for Aerosol and Cloud Chemistry, Aerodyne Research, Inc., Billerica, MA 01821
| | - Carl J Percival
- National Aeronautics and Space Administration Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109
| | - Gordon McFiggans
- Department of Earth and Environmental Science, Centre for Atmospheric Science, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Martin Gallagher
- Department of Earth and Environmental Science, Centre for Atmospheric Science, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Hugh Coe
- Department of Earth and Environmental Science, Centre for Atmospheric Science, University of Manchester, Manchester M13 9PL, United Kingdom
- National Centre for Atmospheric Science, University of Manchester, Manchester M13 9PL, United Kingdom
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7
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Wright MD, Matthews JC, Shallcross DE. A quasi-one-dimensional model for ion-aerosol interactions and aerosol charge state downwind of corona-producing alternating current (AC) HVPL under stable atmospheric conditions. Environ Res 2023; 231:115908. [PMID: 37149026 DOI: 10.1016/j.envres.2023.115908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/31/2023] [Accepted: 04/12/2023] [Indexed: 05/08/2023]
Abstract
Corona ions produced by high voltage power lines (HVPL) can alter the local atmospheric electrical environment downwind, potentially increasing electrostatic charge on airborne particulates via ion-aerosol attachment. However, previous epidemiological assessments attempting to assess this 'corona ion hypothesis' have used proxies e.g. ion concentration or distance from HVPL, rather than aerosol charge state directly, due to difficulties in modeling this quantity. We present a quasi-1D model incorporating both Gaussian plume dynamics and ion-aerosol and ion-ion interaction microphysics which could be applied to future studies of charged aerosol near HVPL. The response of the model to changes in a range of input parameters is characterized, and validation is attempted by means of comparison with previous work where ion- and aerosol concentrations and properties (including electrical mobility and electric charge states) upwind and downwind of HVPL are measured.
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Affiliation(s)
- M D Wright
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, UK; Atmospheric Chemistry Research Group, School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
| | - J C Matthews
- H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, UK; Atmospheric Chemistry Research Group, School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - D E Shallcross
- Atmospheric Chemistry Research Group, School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
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8
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Khan AH, Tait K, Derwent RG, Roome S, Bacak A, Bullock S, Lowenberg MH, Shallcross DE. Off‐setting climate change through formation flying of aircraft, a feasibility study reliant on high fidelity gas‐phase chemical kinetic data. INT J CHEM KINET 2023. [DOI: 10.1002/kin.21644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Affiliation(s)
- Anwar H. Khan
- Atmospheric Chemistry Research Group School of Chemistry Cantock's Close University of Bristol Bristol UK
| | - Kieran Tait
- Department of Aerospace Engineering Queen's Building University Walk University of Bristol Bristol UK
| | | | - Steve Roome
- Department of Aerospace Engineering Queen's Building University Walk University of Bristol Bristol UK
| | - Asan Bacak
- Turkish Accelerator & Radiation Laboratory Ankara University Golbasi, Ankara Turkey
| | - Steve Bullock
- Department of Aerospace Engineering Queen's Building University Walk University of Bristol Bristol UK
| | - Mark H. Lowenberg
- Department of Aerospace Engineering Queen's Building University Walk University of Bristol Bristol UK
| | - Dudley E. Shallcross
- Atmospheric Chemistry Research Group School of Chemistry Cantock's Close University of Bristol Bristol UK
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9
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Matthews JC, Chompoobut C, Navasumrit P, Khan MAH, Wright MD, Ruchirawat M, Shallcross DE. Particle Number Concentration Measurements on Public Transport in Bangkok, Thailand. Int J Environ Res Public Health 2023; 20:5316. [PMID: 37047932 PMCID: PMC10094290 DOI: 10.3390/ijerph20075316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 03/17/2023] [Accepted: 03/22/2023] [Indexed: 06/19/2023]
Abstract
Traffic is a major source of particulate pollution in large cities, and particulate matter (PM) level in Bangkok often exceeds the World Health Organisation limits. While PM2.5 and PM10 are both measured in Bangkok regularly, the sub-micron range of PM, of specific interest in regard to possible adverse health effects, is very limited. In the study, particle number concentration (PNC) was measured on public transport in Bangkok. A travel route through Bangkok using the state railway, the mass rapid transport underground system, the Bangkok Mass Transit System (BTS) Skytrain and public buses on the road network, with walking routes between, was taken whilst measuring particle levels with a hand-held concentration particle counter. The route was repeated 19 times covering different seasons during either morning or evening rush hours. The highest particle concentrations were found on the state railway, followed by the bus, the BTS Skytrain and the MRT underground with measured peaks of 350,000, 330,000, 33,000 and 9000 cm-3, respectively, though particle numbers over 100,000 cm-3 may be an underestimation due to undercounting in the instrument. Inside each form of public transport, particle numbers would peak when stopping to collect passengers (doors opening) and decay with a half-life between 2 and 3 min. There was a weak correlation between particle concentration on bus, train and BTS and Skytrain with carbon monoxide concentration, as measured at a fixed location in the city.
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Affiliation(s)
- James C. Matthews
- Atmospheric Chemistry Research Group, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, UK
| | - Chalida Chompoobut
- Chulabhorn Research Institute, 54 Kamphaeng-Phet 6 Road, Laksi, Bangkok 10210, Thailand
| | - Panida Navasumrit
- Chulabhorn Research Institute, 54 Kamphaeng-Phet 6 Road, Laksi, Bangkok 10210, Thailand
| | - M. Anwar H. Khan
- Atmospheric Chemistry Research Group, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, UK
| | - Matthew D. Wright
- Atmospheric Chemistry Research Group, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, UK
| | - Mathuros Ruchirawat
- Chulabhorn Research Institute, 54 Kamphaeng-Phet 6 Road, Laksi, Bangkok 10210, Thailand
| | - Dudley E. Shallcross
- Atmospheric Chemistry Research Group, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, UK
- Department of Chemistry, University of the Western Cape, Robert Sobukwe Road, Bellville 7375, South Africa
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10
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Holland R, Khan AH, Derwent RG, Lynch J, Ahmed F, Grace S, Bacak A, Shallcross DE. Gas‐phase kinetics, POCPs, and an investigation of the contributions of VOCs to urban ozone production in the UK. INT J CHEM KINET 2023. [DOI: 10.1002/kin.21640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2023]
Affiliation(s)
- Rayne Holland
- School of Chemistry University of Bristol Bristol UK
| | - Anwar H. Khan
- School of Chemistry University of Bristol Bristol UK
| | | | - Josie Lynch
- School of Chemistry University of Bristol Bristol UK
| | - Fahima Ahmed
- School of Chemistry University of Bristol Bristol UK
| | - Sophia Grace
- School of Chemistry University of Bristol Bristol UK
| | - Asan Bacak
- Turkish Accelerator & Radiation Laboratory Ankara University Golbasi Ankara Turkey
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11
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Matthews JC, Navasumrit P, Wright MD, Chaisatra K, Chompoobut C, Arbon R, Khan MAH, Ruchirawat M, Shallcross DE. Aerosol mass and size-resolved metal content in urban Bangkok, Thailand. Environ Sci Pollut Res Int 2022; 29:79025-79040. [PMID: 35705762 PMCID: PMC9587116 DOI: 10.1007/s11356-022-20806-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 05/10/2022] [Indexed: 06/15/2023]
Abstract
Inhalable particulate matter (PM) is a health concern, and people living in large cities such as Bangkok are exposed to high concentrations. This exposure has been linked to respiratory and cardiac diseases and cancers of the lung and brain. Throughout 2018, PM was measured in northern Bangkok near a toll road (13.87°N, 100.58°E) covering all three seasons (cool, hot and rainy). PM10 was measured in 24- and 72-h samples. On selected dates aerodynamic size and mass distribution were measured as 3-day samples from a fixed 5th floor inlet. Particle number concentration was measured from the 5th floor inlet and in roadside survey measurements. There was a large fraction of particle number concentration in the sub-micron range, which showed the greatest variability compared with larger fractions. Metals associated with combustion sources were most found on the smaller size fraction of particles, which may have implications for associated adverse health outcomes because of the likely location of aerosol deposition in the distal airways of the lung. PM10 samples varied between 30 and 100 μg m-3, with highest concentrations in the cool season. The largest metal fractions present in the PM10 measurements were calcium, iron and magnesium during the hot season with average airborne concentrations of 13.2, 3.6 and 2.0 μg m-3, respectively. Copper, zinc, arsenic, selenium, molybdenum, cadmium, antimony and lead had large non-crustal sources. Principal component analysis (PCA) identified likely sources of the metals as crustal minerals, tailpipe exhaust and non-combustion traffic. A health risk analysis showed a higher risk of both carcinogenic and non-carcinogenic health effects in the drier seasons than the wet season due to ingestion of nickel, arsenic, cadmium and lead.
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Affiliation(s)
- James C Matthews
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
| | - Panida Navasumrit
- Laboratory of Environmental Toxicology, Chulabhorn Research Institute, Bangkok, 10210, Thailand
| | - Matthew D Wright
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Krittinee Chaisatra
- Laboratory of Environmental Toxicology, Chulabhorn Research Institute, Bangkok, 10210, Thailand
| | - Chalida Chompoobut
- Laboratory of Environmental Toxicology, Chulabhorn Research Institute, Bangkok, 10210, Thailand
| | - Robert Arbon
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
- Jean Golding Institute, Royal Fort House, University of Bristol, Bristol, BS8 1UH, UK
| | - M Anwar H Khan
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Mathuros Ruchirawat
- Laboratory of Environmental Toxicology, Chulabhorn Research Institute, Bangkok, 10210, Thailand
| | - Dudley E Shallcross
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
- Department of Chemistry, University of the Western Cape, Robert Sobukwe Road, Bellville, 7375, South Africa
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12
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Holland R, Khan MAH, Matthews JC, Bonifacio S, Walters R, Koria P, Clowes J, Rodgers K, Jones T, Patel L, Cross R, Sandberg F, Shallcross DE. Investigating the Variation of Benzene and 1,3-Butadiene in the UK during 2000-2020. Int J Environ Res Public Health 2022; 19:11904. [PMID: 36231204 PMCID: PMC9564389 DOI: 10.3390/ijerph191911904] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/10/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
The concentrations of benzene and 1,3-butadiene in urban, suburban, and rural sites of the U.K. were investigated across 20 years (2000-2020) to assess the impacts of pollution control strategies. Given the known toxicity of these pollutants, it is necessary to investigate national long-term trends across a range of site types. We conclude that whilst legislative intervention has been successful in reducing benzene and 1,3-butadiene pollution from vehicular sources, previously overlooked sources must now be considered as they begin to dominate in contribution to ambient pollution. Benzene concentrations in urban areas were found to be ~5-fold greater than those in rural areas, whilst 1,3-butadiene concentrations were up to ~10-fold greater. The seasonal variation of pollutant concentration exhibited a maximum in the winter and a minimum in the summer with summer: winter ratios of 1:2.5 and 1:1.6 for benzene and 1,3-butadiene, respectively. Across the period investigated (2000-2020), the concentrations of benzene decreased by 85% and 1,3-butadiene concentrations by 91%. A notable difference could be seen between the two decades studied (2000-2010, 2010-2020) with a significantly greater drop evident in the first decade than in the second, proving, whilst previously successful, legislative interventions are no longer sufficiently limiting ambient concentrations of these pollutants. The health impacts of these pollutants are discussed, and cancer impact indices were utilized allowing estimation of cancer impacts across the past 20 years for different site types. Those particularly vulnerable to the adverse health effects of benzene and 1,3-butadiene pollution are discussed.
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Affiliation(s)
- Rayne Holland
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | | | | | | | - Rhian Walters
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | - Priya Koria
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | - Joanna Clowes
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | - Karla Rodgers
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | - Temi Jones
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | - Leeya Patel
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | - Rhianna Cross
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | - Freya Sandberg
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
| | - Dudley E. Shallcross
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
- Department Chemistry, University of the Western Cape, Robert Sobukwe Road, Bellville 7535, South Africa
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13
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Khan MAH, Holland R, Foulds A, Matthews JC, Panditharatne S, Jenkin ME, Lowe D, Navasumrit P, Percival CJ, Shallcross DE. Investigating the background and local contribution of the oxidants in London and Bangkok. Faraday Discuss 2021; 226:515-536. [PMID: 33237098 DOI: 10.1039/d0fd00086h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The contribution of NOx emissions and background O3 to the sources and partitioning of the oxidants [OX (= O3 + NO2)] at the Marylebone Road site in London during the 2000s and 2010s has been investigated to see the impact of the control measures or technology changes inline with the London Mayor's Air Quality Strategy. The abatement of the pollution emissions has an impact on the trends of local and background oxidants, [OX]L and [OX]B, decreasing by 1.4% per year and 0.4% per year, respectively from 2000 to 2019. We also extend our study to three roadside sites (Din Daeng, Thonburi and Chokchai) in another megacity, Bangkok, to compare [OX]L and [OX]B and their behavioural changes with respect to the Marylebone Road site. [OX]L and [OX]B at the Marylebone Road site (0.21[NOx] and 32 ppbv) are comparable with the roadside sites of Thailand (0.12[NOx] to 0.26[NOx] and 29 to 32 ppbv). The seasonal variation of [OX]B levels displays a spring maximum for London, which is due to the higher northern hemispheric ozone baseline, but a maximum during the dry season is found for Bangkok which is likely due to regional-scale long-range transport from the Asian continent. The diurnal variations of [OX]L for both London and Bangkok roadside sites confirm the dominance of the oxidants from road transport emissions, which are found to be higher throughout the daytime. WRF-Chem-CRI model simulations of the distribution of [OX] showed that the model performed well for London background sites when predicting [OX] levels compared with the measured [OX] levels suggesting that the model is treating the chemistry of the oxidants correctly. However, there are large discrepancies for the model-measurement [OX] levels at the traffic site because of the difficulties in the modelling of [OX] at large road networks in megacities for the complex sub grid-scale dynamics that are taking place, both in terms of atmospheric processes and time-varying sources, such as traffic volumes. For roadside sites in Bangkok, the trend in changes of [OX] is predicted by the model correctly but overestimated in absolute magnitude. We suggest that this large deviation is likely to be due to discrepancies in the EDGAR emission inventory (emission overestimates) beyond the resolution of the model.
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Affiliation(s)
- M Anwar H Khan
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
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14
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Say D, Kuyper B, Western L, Khan MAH, Lesch T, Labuschagne C, Martin D, Young D, Manning AJ, O'Doherty S, Rigby M, Krummel PB, Davies-Coleman MT, Ganesan AL, Shallcross DE. Emissions and Marine Boundary Layer Concentrations of Unregulated Chlorocarbons Measured at Cape Point, South Africa. Environ Sci Technol 2020; 54:10514-10523. [PMID: 32786594 DOI: 10.1021/acs.est.0c02057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Unregulated chlorocarbons, here defined as dichloromethane (CH2Cl2), perchloroethene (C2Cl4), chloroform (CHCl3), and methyl chloride (CH3Cl), are gases not regulated by the Montreal Protocol. While CH3Cl is the largest contributor of atmospheric chlorine, recent studies have shown that growth in emissions of the less abundant chlorocarbons could pose a significant threat to the recovery of the ozone layer. Despite this, there remain many regions for which no atmospheric monitoring exists, leaving gaps in our understanding of global emissions. Here, we report on a new time series of chlorocarbon measurements from Cape Point, South Africa for 2017, which represent the first published high-frequency measurements of these gases from Africa. For CH2Cl2 and C2Cl4, the majority of mole fraction enhancements were observed from the north, consistent with anthropogenically modified air from Cape Town, while for CHCl3 and CH3Cl, we found evidence for both oceanic and terrestrial sources. Using an inverse method, we estimated emissions for south-western South Africa (SWSA). For each chlorocarbon, SWSA accounted for less than 1% of global emissions. For CH2Cl2 and C2Cl4, we extrapolated using population statistics and found South African emissions of 8.9 (7.4-10.4) Gg yr-1 and 0.80 (0.64-1.04) Gg yr-1, respectively.
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Affiliation(s)
- Daniel Say
- Atmospheric Chemistry Research Group, University of Bristol, Bristol BS8 1TS, UK
| | - Brett Kuyper
- Department of Chemistry, University of the Western Cape, Robert Sobukwe Rd, Bellville, Cape Town 7535, South Africa
| | - Luke Western
- Atmospheric Chemistry Research Group, University of Bristol, Bristol BS8 1TS, UK
| | - M Anwar H Khan
- Atmospheric Chemistry Research Group, University of Bristol, Bristol BS8 1TS, UK
| | - Timothy Lesch
- Department of Chemistry, University of the Western Cape, Robert Sobukwe Rd, Bellville, Cape Town 7535, South Africa
| | | | - Damien Martin
- School of Physics, Ryan Institute's Centre for Climate and Pollution Studies, and Marine Renewable Energy Ireland, National University of Ireland, Galway H91 CF50, Ireland
| | - Dickon Young
- Atmospheric Chemistry Research Group, University of Bristol, Bristol BS8 1TS, UK
| | | | - Simon O'Doherty
- Atmospheric Chemistry Research Group, University of Bristol, Bristol BS8 1TS, UK
| | - Matthew Rigby
- Atmospheric Chemistry Research Group, University of Bristol, Bristol BS8 1TS, UK
| | - Paul B Krummel
- Climate Science Centre, CSIRO Oceans and Atmosphere, Aspendale 3195, Australia
| | - Michael T Davies-Coleman
- Department of Chemistry, University of the Western Cape, Robert Sobukwe Rd, Bellville, Cape Town 7535, South Africa
| | - Anita L Ganesan
- School of Geographical Sciences, University of Bristol, Bristol BS8 1SS, UK
| | - Dudley E Shallcross
- Atmospheric Chemistry Research Group, University of Bristol, Bristol BS8 1TS, UK
- Department of Chemistry, University of the Western Cape, Robert Sobukwe Rd, Bellville, Cape Town 7535, South Africa
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15
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Usmani OS, Matthews JC, Wright MD, Meah S, Underwood SR, Barnes PJ, Shallcross DE, Biddiscombe MF. No Evidence That Electric Charge Increases Inhaled Ultrafine Particle Deposition in Human Lungs. Am J Respir Crit Care Med 2020; 201:1301-1303. [PMID: 31995394 DOI: 10.1164/rccm.201912-2502le] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
| | | | | | - Sally Meah
- Imperial College LondonLondon, United Kingdom
| | - S Richard Underwood
- Royal Brompton Hospital & Harefield NHS Foundation TrustLondon, United Kingdom
| | | | | | - Martyn F Biddiscombe
- Imperial College LondonLondon, United Kingdom.,Royal Brompton Hospital & Harefield NHS Foundation TrustLondon, United Kingdom
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16
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Affiliation(s)
| | | | - Craig A. Taatjes
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA, USA
| | - Carl J. Percival
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
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17
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Wright MD, Matthews JC, Silva HG, Bacak A, Percival C, Shallcross DE. The relationship between aerosol concentration and atmospheric potential gradient in urban environments. Sci Total Environ 2020; 716:134959. [PMID: 31837845 DOI: 10.1016/j.scitotenv.2019.134959] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 10/10/2019] [Accepted: 10/11/2019] [Indexed: 06/10/2023]
Abstract
Urban aerosol is a growing concern for people living within cities; aerosol have been implicated in many ill health conditions, including that of the lung and of the heart. Atmospheric potential gradient is a consequence of charge carried to the ionosphere through thunderstorms, and its value depends on highly electrically mobile ion concentrations, hence local conductivity of the air. Ions attach to aerosol in the atmosphere, reducing their mobility and therefore increasing the potential gradient, and so potential gradient measurements have been suggested as a proxy for aerosol measurements. Particle number count, size distribution and potential gradient were measured for two campaigns in Manchester, U.K., and one campaign in Bristol, U.K. Using a factor based on size distribution to account for preferential attachment at larger sizes provided the best relationship with potential gradient, but particle count alone showed a weaker, but similar relationship. The increase in particle count caused by annual bonfire and fireworks celebrations (November) was evidenced in both potential gradient and particle numbers. Daily regression or correlation did not show a consistent relationship. In the larger Bristol data set, increasing humidity led to a reduction of potential gradient, while increasing particle number led to an increase.
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Affiliation(s)
- M D Wright
- School of Chemistry, Cantocks Close, University of Bristol, Bristol, UK
| | - J C Matthews
- School of Chemistry, Cantocks Close, University of Bristol, Bristol, UK.
| | - H G Silva
- Physics Department, Institute of Earth Sciences, University of Évora, Rua Romão Ramalho 59, 7002-671 Évora, Portugal
| | - A Bacak
- School of Earth and Atmospheric Science, Oxford Road, University of Manchester, UK
| | - C Percival
- School of Earth and Atmospheric Science, Oxford Road, University of Manchester, UK
| | - D E Shallcross
- School of Chemistry, Cantocks Close, University of Bristol, Bristol, UK
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18
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Vansco MF, Caravan RL, Zuraski K, Winiberg FAF, Au K, Trongsiriwat N, Walsh PJ, Osborn DL, Percival CJ, Khan MAH, Shallcross DE, Taatjes CA, Lester MI. Experimental Evidence of Dioxole Unimolecular Decay Pathway for Isoprene-Derived Criegee Intermediates. J Phys Chem A 2020; 124:3542-3554. [PMID: 32255634 DOI: 10.1021/acs.jpca.0c02138] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Ozonolysis of isoprene, one of the most abundant volatile organic compounds emitted into the Earth's atmosphere, generates two four-carbon unsaturated Criegee intermediates, methyl vinyl ketone oxide (MVK-oxide) and methacrolein oxide (MACR-oxide). The extended conjugation between the vinyl substituent and carbonyl oxide groups of these Criegee intermediates facilitates rapid electrocyclic ring closures that form five-membered cyclic peroxides, known as dioxoles. This study reports the first experimental evidence of this novel decay pathway, which is predicted to be the dominant atmospheric sink for specific conformational forms of MVK-oxide (anti) and MACR-oxide (syn) with the vinyl substituent adjacent to the terminal O atom. The resulting dioxoles are predicted to undergo rapid unimolecular decay to oxygenated hydrocarbon radical products, including acetyl, vinoxy, formyl, and 2-methylvinoxy radicals. In the presence of O2, these radicals rapidly react to form peroxy radicals (ROO), which quickly decay via carbon-centered radical intermediates (QOOH) to stable carbonyl products that were identified in this work. The carbonyl products were detected under thermal conditions (298 K, 10 Torr He) using multiplexed photoionization mass spectrometry (MPIMS). The main products (and associated relative abundances) originating from unimolecular decay of anti-MVK-oxide and subsequent reaction with O2 are formaldehyde (88 ± 5%), ketene (9 ± 1%), and glyoxal (3 ± 1%). Those identified from the unimolecular decay of syn-MACR-oxide and subsequent reaction with O2 are acetaldehyde (37 ± 7%), vinyl alcohol (9 ± 1%), methylketene (2 ± 1%), and acrolein (52 ± 5%). In addition to the stable carbonyl products, the secondary peroxy chemistry also generates OH or HO2 radical coproducts.
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Affiliation(s)
- Michael F Vansco
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Rebecca L Caravan
- NASA Postdoctoral Program, NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States.,Combustion Research Facility, Sandia National Laboratories, Mailstop 9055, Livermore, California 94551, United States.,Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Kristen Zuraski
- NASA Postdoctoral Program, NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Frank A F Winiberg
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States.,California Institute of Technology, Pasadena, California 91125, United States
| | - Kendrew Au
- Combustion Research Facility, Sandia National Laboratories, Mailstop 9055, Livermore, California 94551, United States
| | - Nisalak Trongsiriwat
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Patrick J Walsh
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - David L Osborn
- Combustion Research Facility, Sandia National Laboratories, Mailstop 9055, Livermore, California 94551, United States
| | - Carl J Percival
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States.,California Institute of Technology, Pasadena, California 91125, United States
| | - M Anwar H Khan
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Dudley E Shallcross
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Craig A Taatjes
- Combustion Research Facility, Sandia National Laboratories, Mailstop 9055, Livermore, California 94551, United States
| | - Marsha I Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
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19
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Kuyper B, Say D, Labuschagne C, Lesch T, Joubert WR, Martin D, Young D, Khan MAH, Rigby M, Ganesan AL, Lunt MF, O'Dowd C, Manning AJ, O'Doherty S, Davies-Coleman MT, Shallcross DE. Atmospheric HCFC-22, HFC-125, and HFC-152a at Cape Point, South Africa. Environ Sci Technol 2019; 53:8967-8975. [PMID: 31251602 DOI: 10.1021/acs.est.9b01612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
One hydrochlorofluorocarbon and two hydrofluorocarbons (HCFC-22, HFC-125, and HFC-152a) were measured in air samples at the Cape Point observatory (CPT), South Africa, during 2017. These data represent the first such atmospheric measurements of these compounds from southwestern South Africa (SWSA). Baseline atmospheric growth rates were estimated to be 8.36, 4.10, and 0.71 ppt year-1 for HCFC-22, HFC-125, and HFC-152a, respectively. The CPT measurements were combined with an inverse model to investigate emissions from SWSA. For all three halocarbons, Cape Town was found to be the dominant source within SWSA. These estimates were extrapolated, based on population statistics, to estimate emissions for the whole of South Africa. We estimate South Africa's 2017 emissions to be 3.0 (1.6-4.4), 0.8 (0.5-1.2), and 1.1 (0.6-1.6) Gg year-1 for HCFC-22, HFC-125, and HFC-152a, respectively. For all three halocarbons, South Africa's contribution to global emissions is small (<2.5%), but future monitoring is needed to ensure South Africa's compliance with regulation set out by the Montreal Protocol and its Amendments.
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Affiliation(s)
- Brett Kuyper
- Department of Chemistry , University of the Western Cape , Bellville 7535 , South Africa
| | - Daniel Say
- Atmospheric Chemistry Research Group, School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
| | - Casper Labuschagne
- Climate and Environmental Research and Monitoring , South African Weather Service , Stellenbosch 7600 , South Africa
| | - Timothy Lesch
- Department of Chemistry , University of the Western Cape , Bellville 7535 , South Africa
| | - Warren R Joubert
- Climate and Environmental Research and Monitoring , South African Weather Service , Stellenbosch 7600 , South Africa
| | - Damien Martin
- Atmospheric Chemistry Research Group, School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
- School of Physics, Ryan Institute's Centre for Climate and & Pollution Studies, and Marine Renewable Energy Ireland , National University of Ireland Galway , Galway H91 CF50 , Ireland
| | - Dickon Young
- Atmospheric Chemistry Research Group, School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
| | - M Anwar H Khan
- Atmospheric Chemistry Research Group, School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
| | - Matthew Rigby
- Atmospheric Chemistry Research Group, School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
| | - Anita L Ganesan
- School of Geographical Sciences , University of Bristol , Bristol BS8 1SS , United Kingdom
| | - Mark F Lunt
- School of Geosciences , University of Edinburgh , Edinburgh EH9 3JW , United Kingdom
| | - Colin O'Dowd
- School of Physics, Ryan Institute's Centre for Climate and & Pollution Studies, and Marine Renewable Energy Ireland , National University of Ireland Galway , Galway H91 CF50 , Ireland
| | - Alistair J Manning
- Atmospheric Chemistry Research Group, School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
- Hadley Centre, The Met Office , Exeter EX1 3PB , United Kingdom
| | - Simon O'Doherty
- Atmospheric Chemistry Research Group, School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
| | | | - Dudley E Shallcross
- Department of Chemistry , University of the Western Cape , Bellville 7535 , South Africa
- Atmospheric Chemistry Research Group, School of Chemistry , University of Bristol , Bristol BS8 1TS , United Kingdom
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20
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Allen G, Hollingsworth P, Kabbabe K, Pitt JR, Mead MI, Illingworth S, Roberts G, Bourn M, Shallcross DE, Percival CJ. The development and trial of an unmanned aerial system for the measurement of methane flux from landfill and greenhouse gas emission hotspots. Waste Manag 2019; 87:883-892. [PMID: 29329657 DOI: 10.1016/j.wasman.2017.12.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 12/12/2017] [Accepted: 12/18/2017] [Indexed: 06/07/2023]
Abstract
This paper describes the development of a new sampling and measurement method to infer methane flux using proxy measurements of CO2 concentration and wind data recorded by Unmanned Aerial Systems (UAS). The flux method described and trialed here is appropriate to the spatial scale of landfill sites and analogous greenhouse gas emission hotspots, making it an important new method for low-cost and rapid case study quantification of fluxes from currently uncertain (but highly important) greenhouse gas sources. We present a case study using these UAS-based measurements to derive instantaneous methane fluxes from a test landfill site in the north of England using a mass balance model tailored for UAS sampling and co-emitted CO2 concentration as a methane-emission proxy. Methane flux (and flux uncertainty) during two trials on 27 November 2014 and 5 March 2015, were found to be 0.140 kg s-1 (±61% at 1σ), and 0.050 kg s-1 (±54% at 1σ), respectively. Uncertainty contributing to the flux was dominated by ambient variability in the background (inflow) concentration (>40%) and wind speed (>10%); with instrumental error contributing only ∼1-2%. The approach described represents an important advance concerning the challenging problem of greenhouse gas hotspot flux calculation, and offers transferability to a wide range of analogous environments. This new measurement solution could add to a toolkit of approaches to better validate source-specific greenhouse emissions inventories - an important new requirement of the UNFCCC COP21 (Paris) climate change agreement.
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Affiliation(s)
- Grant Allen
- Centre for Atmospheric Science, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Peter Hollingsworth
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Khristopher Kabbabe
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Joseph R Pitt
- Centre for Atmospheric Science, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Mohammed I Mead
- Centre for Atmospheric Science, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Samuel Illingworth
- Centre for Atmospheric Science, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Gareth Roberts
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Mark Bourn
- Environment Agency, Horizon House, Deanery Road, Bristol BS1 5AH, UK
| | | | - Carl J Percival
- Centre for Atmospheric Science, University of Manchester, Oxford Road, Manchester M13 9PL, UK
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21
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Taatjes CA, Khan MAH, Eskola AJ, Percival CJ, Osborn DL, Wallington TJ, Shallcross DE. Reaction of Perfluorooctanoic Acid with Criegee Intermediates and Implications for the Atmospheric Fate of Perfluorocarboxylic Acids. Environ Sci Technol 2019; 53:1245-1251. [PMID: 30589541 DOI: 10.1021/acs.est.8b05073] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The reaction of perfluorooctanoic acid with the smallest carbonyl oxide Criegee intermediate, CH2OO, has been measured and is very rapid, with a rate coefficient of (4.9 ± 0.8) × 10-10 cm3 s-1, similar to that for reactions of Criegee intermediates with other organic acids. Evidence is shown for the formation of hydroperoxymethyl perfluorooctanoate as a product. With such a large rate coefficient, reaction with Criegee intermediates can be a substantial contributor to atmospheric removal of perfluorocarboxylic acids. However, the atmospheric fates of the ester product largely regenerate the initial acid reactant. Wet deposition regenerates the perfluorocarboxylic acid via condensed-phase hydrolysis. Gas-phase reaction with OH is expected principally to result in formation of the acid anhydride, which also hydrolyzes to regenerate the acid, although a minor channel could lead to destruction of the perfluorinated backbone.
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Affiliation(s)
- Craig A Taatjes
- Combustion Research Facility, Mail Stop 9055 , Sandia National Laboratories, Livermore , California 94551-0969 United States
| | - M Anwar H Khan
- School of Chemistry , The University of Bristol , Cantock's Close BS8 1TS , Bristol , U.K
| | - Arkke J Eskola
- Combustion Research Facility, Mail Stop 9055 , Sandia National Laboratories, Livermore , California 94551-0969 United States
- Department of Chemistry , University of Helsinki , P.O. Box 55 (A.I. Virtasen aukio 1) , FI-00014 Helsinki , Finland
| | - Carl J Percival
- The Centre for Atmospheric Science, The School of Earth, Atmospheric and Environmental Science , The University of Manchester , Simon Building, Brunswick Street , Manchester , M13 9PL , U.K
- Jet Propulsion Laboratory , California Institute of Technology , 4800 Oak Grove Drive , Pasadena , California 91109 United States
| | - David L Osborn
- Combustion Research Facility, Mail Stop 9055 , Sandia National Laboratories, Livermore , California 94551-0969 United States
| | - Timothy J Wallington
- Research & Advanced Engineering , Ford Motor Company , Dearborn , Michigan 48121 United States
| | - Dudley E Shallcross
- School of Chemistry , The University of Bristol , Cantock's Close BS8 1TS , Bristol , U.K
- Department of Chemistry , University of the Western Cape , Robert Sobukwe Road , Bellville 7535 , South Africa
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22
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Chhantyal-Pun R, Shannon RJ, Tew DP, Caravan RL, Duchi M, Wong C, Ingham A, Feldman C, McGillen MR, Khan MAH, Antonov IO, Rotavera B, Ramasesha K, Osborn DL, Taatjes CA, Percival CJ, Shallcross DE, Orr-Ewing AJ. Experimental and computational studies of Criegee intermediate reactions with NH3 and CH3NH2. Phys Chem Chem Phys 2019; 21:14042-14052. [DOI: 10.1039/c8cp06810k] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The significance of removal of atmospheric ammonia and amines by reaction with Criegee intermediates is assessed by kinetic studies.
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23
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Caravan RL, Khan MAH, Zádor J, Sheps L, Antonov IO, Rotavera B, Ramasesha K, Au K, Chen MW, Rösch D, Osborn DL, Fittschen C, Schoemaecker C, Duncianu M, Grira A, Dusanter S, Tomas A, Percival CJ, Shallcross DE, Taatjes CA. The reaction of hydroxyl and methylperoxy radicals is not a major source of atmospheric methanol. Nat Commun 2018; 9:4343. [PMID: 30341291 PMCID: PMC6195545 DOI: 10.1038/s41467-018-06716-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 08/05/2018] [Indexed: 11/18/2022] Open
Abstract
Methanol is a benchmark for understanding tropospheric oxidation, but is underpredicted by up to 100% in atmospheric models. Recent work has suggested this discrepancy can be reconciled by the rapid reaction of hydroxyl and methylperoxy radicals with a methanol branching fraction of 30%. However, for fractions below 15%, methanol underprediction is exacerbated. Theoretical investigations of this reaction are challenging because of intersystem crossing between singlet and triplet surfaces - ∼45% of reaction products are obtained via intersystem crossing of a pre-product complex - which demands experimental determinations of product branching. Here we report direct measurements of methanol from this reaction. A branching fraction below 15% is established, consequently highlighting a large gap in the understanding of global methanol sources. These results support the recent high-level theoretical work and substantially reduce its uncertainties.
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Affiliation(s)
- Rebecca L Caravan
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA.
| | - M Anwar H Khan
- School of Chemistry, Cantock's Close, University of Bristol, Bristol, BS8 1TS, UK
| | - Judit Zádor
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Leonid Sheps
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Ivan O Antonov
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Brandon Rotavera
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Krupa Ramasesha
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Kendrew Au
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Ming-Wei Chen
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Daniel Rösch
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - David L Osborn
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Christa Fittschen
- Université Lille, CNRS, UMR 8522-PC2A-Physicochimie des Processus de Combustion et de l'Atmosphère, 59000, Lille, France
| | - Coralie Schoemaecker
- Université Lille, CNRS, UMR 8522-PC2A-Physicochimie des Processus de Combustion et de l'Atmosphère, 59000, Lille, France
| | - Marius Duncianu
- IMT Lille Douai, Université Lille, Département Sciences de l'Atmosphère et Génie de l'Environnement (SAGE), 59000, Lille, France
| | - Asma Grira
- IMT Lille Douai, Université Lille, Département Sciences de l'Atmosphère et Génie de l'Environnement (SAGE), 59000, Lille, France
| | - Sebastien Dusanter
- IMT Lille Douai, Université Lille, Département Sciences de l'Atmosphère et Génie de l'Environnement (SAGE), 59000, Lille, France
| | - Alexandre Tomas
- IMT Lille Douai, Université Lille, Département Sciences de l'Atmosphère et Génie de l'Environnement (SAGE), 59000, Lille, France
| | - Carl J Percival
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA
| | - Dudley E Shallcross
- School of Chemistry, Cantock's Close, University of Bristol, Bristol, BS8 1TS, UK.
| | - Craig A Taatjes
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA.
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24
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Eskola AJ, Döntgen M, Rotavera B, Caravan RL, Welz O, Savee JD, Osborn DL, Shallcross DE, Percival CJ, Taatjes CA. Direct kinetics study of CH 2OO + methyl vinyl ketone and CH 2OO + methacrolein reactions and an upper limit determination for CH 2OO + CO reaction. Phys Chem Chem Phys 2018; 20:19373-19381. [PMID: 29999060 DOI: 10.1039/c8cp03606c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Methyl vinyl ketone (MVK) and methacrolein (MACR) are important intermediate products in atmospheric degradation of volatile organic compounds, especially of isoprene. This work investigates the reactions of the smallest Criegee intermediate, CH2OO, with its co-products from isoprene ozonolysis, MVK and MACR, using multiplexed photoionization mass spectrometry (MPIMS), with either tunable synchrotron radiation from the Advanced Light Source or Lyman-α (10.2 eV) radiation for photoionization. CH2OO was produced via pulsed laser photolysis of CH2I2 in the presence of excess O2. Time-resolved measurements of reactant disappearance and of product formation were performed to monitor reaction progress; first order rate coefficients were obtained from exponential fits to the CH2OO decays. The bimolecular reaction rate coefficients at 300 K and 4 Torr are k(CH2OO + MVK) = (5.0 ± 0.4) × 10-13 cm3 s-1 and k(CH2OO + MACR) = (4.4 ± 1.0) × 10-13 cm3 s-1, where the stated ±2σ uncertainties are statistical uncertainties. Adduct formation is observed for both reactions and is attributed to the formation of a secondary ozonides (1,2,4-trioxolanes), supported by master equation calculations of the kinetics and the agreement between measured and calculated adiabatic ionization energies. Kinetics measurements were also performed for a possible bimolecular CH2OO + CO reaction and for the reaction of CH2OO with CF3CHCH2 at 300 K and 4 Torr. For CH2OO + CO, no reaction is observed and an upper limit is determined: k(CH2OO + CO) < 2 × 10-16 cm3 s-1. For CH2OO + CF3CHCH2, an upper limit of k(CH2OO + CF3CHCH2) < 2 × 10-14 cm3 s-1 is obtained.
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Affiliation(s)
- Arkke J Eskola
- Combustion Research Facility, Sandia National Laboratories, 7011 East Avenue, MS 9055, Livermore, California 94551, USA.
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25
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Labuschagne C, Kuyper B, Brunke EG, Mokolo T, van der Spuy D, Martin L, Mbambalala E, Parker B, Khan MAH, Davies-Coleman MT, Shallcross DE, Joubert W. A review of four decades of atmospheric trace gas measurements at Cape Point, South Africa. ACTA ACUST UNITED AC 2018. [DOI: 10.1080/0035919x.2018.1477854] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Casper Labuschagne
- Global Atmospheric Watch, South African Weather Service, Stellenbosch, South Africa
| | - Brett Kuyper
- Department of Chemistry, University of the Western Cape, Cape Town, South Africa
| | - Ernst-Günther Brunke
- Global Atmospheric Watch, South African Weather Service, Stellenbosch, South Africa
| | - Thumeka Mokolo
- Global Atmospheric Watch, South African Weather Service, Stellenbosch, South Africa
| | - Danie van der Spuy
- Global Atmospheric Watch, South African Weather Service, Stellenbosch, South Africa
| | - Lynwill Martin
- Global Atmospheric Watch, South African Weather Service, Stellenbosch, South Africa
| | - Ernst Mbambalala
- Global Atmospheric Watch, South African Weather Service, Stellenbosch, South Africa
| | - Bhawoodien Parker
- Global Atmospheric Watch, South African Weather Service, Stellenbosch, South Africa
- Department of Environmental Affairs and Development Planning, Western Cape Government, South Africa
| | - M. Anwar H. Khan
- Atmospheric Chemistry Research Group, School of Chemistry, University of Bristol, United Kingdom
| | | | - Dudley E. Shallcross
- Department of Chemistry, University of the Western Cape, Cape Town, South Africa
- Atmospheric Chemistry Research Group, School of Chemistry, University of Bristol, United Kingdom
| | - Warren Joubert
- Global Atmospheric Watch, South African Weather Service, Stellenbosch, South Africa
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26
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Khan MAH, Percival CJ, Caravan RL, Taatjes CA, Shallcross DE. Criegee intermediates and their impacts on the troposphere. Environ Sci Process Impacts 2018; 20:437-453. [PMID: 29480909 DOI: 10.1039/c7em00585g] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Criegee intermediates (CIs), carbonyl oxides formed in ozonolysis of alkenes, play key roles in the troposphere. The decomposition of CIs can be a significant source of OH to the tropospheric oxidation cycle especially during nighttime and winter months. A variety of model-measurement studies have estimated surface-level stabilized Criegee intermediate (sCI) concentrations on the order of 1 × 104 cm-3 to 1 × 105 cm-3, which makes a non-negligible contribution to the oxidising capacity in the terrestrial boundary layer. The reactions of sCI with the water monomer and the water dimer have been found to be the most important bimolecular reactions to the tropospheric sCI loss rate, at least for the smallest carbonyl oxides; the products from these reactions (e.g. hydroxymethyl hydroperoxide, HMHP) are also of importance to the atmospheric oxidation cycle. The sCI can oxidise SO2 to form SO3, which can go on to form a significant amount of H2SO4 which is a key atmospheric nucleation species and therefore vital to the formation of clouds. The sCI can also react with carboxylic acids, carbonyl compounds, alcohols, peroxy radicals and hydroperoxides, and the products of these reactions are likely to be highly oxygenated species, with low vapour pressures, that can lead to nucleation and SOA formation over terrestrial regions.
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Affiliation(s)
- M A H Khan
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
| | - C J Percival
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr, Pasadena, CA 91109, USA
| | - R L Caravan
- Combustion Research Facility, Sandia National Laboratories, Mailstop 9055, Livermore, California, 94551 USA
| | - C A Taatjes
- Combustion Research Facility, Sandia National Laboratories, Mailstop 9055, Livermore, California, 94551 USA
| | - D E Shallcross
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
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27
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Sheps L, Rotavera B, Eskola AJ, Osborn DL, Taatjes CA, Au K, Shallcross DE, Khan MAH, Percival CJ. The reaction of Criegee intermediate CH 2OO with water dimer: primary products and atmospheric impact. Phys Chem Chem Phys 2018; 19:21970-21979. [PMID: 28805226 DOI: 10.1039/c7cp03265j] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The rapid reaction of the smallest Criegee intermediate, CH2OO, with water dimers is the dominant removal mechanism for CH2OO in the Earth's atmosphere, but its products are not well understood. This reaction was recently suggested as a significant source of the most abundant tropospheric organic acid, formic acid (HCOOH), which is consistently underpredicted by atmospheric models. However, using time-resolved measurements of reaction kinetics by UV absorption and product analysis by photoionization mass spectrometry, we show that the primary products of this reaction are formaldehyde and hydroxymethyl hydroperoxide (HMHP), with direct HCOOH yields of less than 10%. Incorporating our results into a global chemistry-transport model further reduces HCOOH levels by 10-90%, relative to previous modeling assumptions, which indicates that the reaction CH2OO + water dimer by itself cannot resolve the discrepancy between the measured and predicted HCOOH levels.
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Affiliation(s)
- Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, 7011 East Ave., MS 9055, Livermore, California 94551, USA.
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28
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Winiberg FAF, Percival CJ, Shannon R, Khan MAH, Shallcross DE, Liu Y, Sander SP. Reaction kinetics of OH + HNO3 under conditions relevant to the upper troposphere/lower stratosphere. Phys Chem Chem Phys 2018; 20:24652-24664. [DOI: 10.1039/c8cp04193h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Key upper atmosphere reaction of HNO3 + OH studied over extended pressure and temperature range using new alternative detection method.
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Affiliation(s)
| | - Carl J. Percival
- NASA Jet Propulsion Laboratory
- California Institute of Technology
- Pasadena
- USA
| | - Robin Shannon
- School of Chemistry
- Cantock's Close
- University of Bristol
- Bristol
- UK
| | - M. Anwar H. Khan
- School of Chemistry
- Cantock's Close
- University of Bristol
- Bristol
- UK
| | | | - Yingdi Liu
- NASA Jet Propulsion Laboratory
- California Institute of Technology
- Pasadena
- USA
| | - Stanley P. Sander
- NASA Jet Propulsion Laboratory
- California Institute of Technology
- Pasadena
- USA
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29
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H. Khan MA, Morris WC, Galloway M, A. Shallcross B, Percival CJ, Shallcross DE. An Estimation of the Levels of Stabilized Criegee Intermediates in the UK Urban and Rural Atmosphere Using the Steady-State Approximation and the Potential Effects of These Intermediates on Tropospheric Oxidation Cycles. INT J CHEM KINET 2017; 49:611-621. [PMID: 28781420 PMCID: PMC5519938 DOI: 10.1002/kin.21101] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/05/2017] [Accepted: 05/05/2017] [Indexed: 01/18/2023]
Abstract
Levels of the stabilized Criegee Intermediate (sCI), produced via the ozonolysis of unsaturated volatile organic compounds (VOCs), were estimated at two London urban sites (Marylebone Road and Eltham) and one rural site (Harwell) in the UK over the period of 1998-2012. The steady-state approximation was applied to data obtained from the NETCEN (National Environmental Technology Centre) database, and the levels of annual average sCI were estimated to be in the range of 30-3000 molecules cm-3 for UK sites. A consistent diurnal cycle of sCI concentration is estimated for the UK sites with increasing levels during daylight hours, peaking just after midday. The seasonal pattern of sCI shows higher levels in spring with peaks around May due to the higher levels of O3. The ozone weekend effect resulted in higher sCI in UK urban areas during weekend. The sCI data were modeled using the information provided by the Air Quality Improvement Research Program (AQIRP) and found that the modeled production was five- to six-fold higher than our estimated data, and therefore the estimated sCI concentrations in this study are thought to be lower estimates only. Compared with nighttime, 1.3- to 1.8-fold higher sCI exists under daytime conditions. Using the levels of sCI estimated at Marylebone Road, globally the oxidation rates of NO2 + sCI (22.4 Gg/yr) and SO2 + sCI (37.6 Gg/yr) in urban areas can increase their effect in the troposphere and potentially further alter the oxidizing capacity of the troposphere. Further investigations of modeled sCI show that CH3CHOO (64%) and CH2OO (13%) are dominant among all contributing sCI at the UK sites.
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Affiliation(s)
- M. Anwar H. Khan
- Atmospheric Chemistry Research GroupSchool of ChemistryUniversity of BristolBristolBS8 1TSUK
| | - William C. Morris
- Atmospheric Chemistry Research GroupSchool of ChemistryUniversity of BristolBristolBS8 1TSUK
| | - Matthew Galloway
- Atmospheric Chemistry Research GroupSchool of ChemistryUniversity of BristolBristolBS8 1TSUK
| | | | | | - Dudley E. Shallcross
- Atmospheric Chemistry Research GroupSchool of ChemistryUniversity of BristolBristolBS8 1TSUK
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30
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Chhantyal-Pun R, McGillen MR, Beames JM, Khan MAH, Percival CJ, Shallcross DE, Orr-Ewing AJ. Temperature-Dependence of the Rates of Reaction of Trifluoroacetic Acid with Criegee Intermediates. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201703700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Rabi Chhantyal-Pun
- School of Chemistry; University of Bristol; Cantock's Close Bristol BS8 1TS UK
| | - Max R. McGillen
- School of Chemistry; University of Bristol; Cantock's Close Bristol BS8 1TS UK
| | - Joseph M. Beames
- School of Chemistry; Cardiff University; Main Building, Park Place Cardiff CF10 3AT UK
| | - M. Anwar H. Khan
- School of Chemistry; University of Bristol; Cantock's Close Bristol BS8 1TS UK
| | - Carl J. Percival
- Jet Propulsion Laboratory; Mail Stop 183-901; 4800 Oak Grove Drive Pasadena CA 92209 USA
| | | | - Andrew J. Orr-Ewing
- School of Chemistry; University of Bristol; Cantock's Close Bristol BS8 1TS UK
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31
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Chhantyal-Pun R, McGillen MR, Beames JM, Khan MAH, Percival CJ, Shallcross DE, Orr-Ewing AJ. Temperature-Dependence of the Rates of Reaction of Trifluoroacetic Acid with Criegee Intermediates. Angew Chem Int Ed Engl 2017; 56:9044-9047. [PMID: 28614628 PMCID: PMC5575497 DOI: 10.1002/anie.201703700] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/07/2017] [Indexed: 11/11/2022]
Abstract
The rate coefficients for gas-phase reaction of trifluoroacetic acid (TFA) with two Criegee intermediates, formaldehyde oxide and acetone oxide, decrease with increasing temperature in the range 240-340 K. The rate coefficients k(CH2 OO + CF3 COOH)=(3.4±0.3)×10-10 cm3 s-1 and k((CH3 )2 COO + CF3 COOH)=(6.1±0.2)×10-10 cm3 s-1 at 294 K exceed estimates for collision-limited values, suggesting rate enhancement by capture mechanisms because of the large permanent dipole moments of the two reactants. The observed temperature dependence is attributed to competitive stabilization of a pre-reactive complex. Fits to a model incorporating this complex formation give k [cm3 s-1 ]=(3.8±2.6)×10-18 T2 exp((1620±180)/T) + 2.5×10-10 and k [cm3 s-1 ]=(4.9±4.1)×10-18 T2 exp((1620±230)/T) + 5.2×10-10 for the CH2 OO + CF3 COOH and (CH3 )2 COO + CF3 COOH reactions, respectively. The consequences are explored for removal of TFA from the atmosphere by reaction with biogenic Criegee intermediates.
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Affiliation(s)
- Rabi Chhantyal-Pun
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Max R McGillen
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Joseph M Beames
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
| | - M Anwar H Khan
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Carl J Percival
- Jet Propulsion Laboratory, Mail Stop 183-901, 4800 Oak Grove Drive, Pasadena, CA, 92209, USA
| | - Dudley E Shallcross
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Andrew J Orr-Ewing
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
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32
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Caravan RL, Khan MAH, Rotavera B, Papajak E, Antonov IO, Chen MW, Au K, Chao W, Osborn DL, Lin JJM, Percival CJ, Shallcross DE, Taatjes CA. Products of Criegee intermediate reactions with NO2: experimental measurements and tropospheric implications. Faraday Discuss 2017; 200:313-330. [DOI: 10.1039/c7fd00007c] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reactions of Criegee intermediates with NO2 have been proposed as a potentially significant source of the important nighttime oxidant NO3, particularly in urban environments where concentrations of ozone, alkenes and NOx are high. However, previous efforts to characterize the yield of NO3 from these reactions have been inconclusive, with many studies failing to detect NO3. In the present work, the reactions of formaldehyde oxide (CH2OO) and acetaldehyde oxide (CH3CHOO) with NO2 are revisited to further explore the product formation over a pressure range of 4–40 Torr. NO3 is not observed; however, temporally resolved and [NO2]-dependent signal is observed at the mass of the Criegee–NO2 adduct for both formaldehyde- and acetaldehyde-oxide systems, and the structure of this adduct is explored through ab initio calculations. The atmospheric implications of the title reaction are investigated through global modelling.
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33
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Chhantyal-Pun R, Welz O, Savee JD, Eskola AJ, Lee EPF, Blacker L, Hill HR, Ashcroft M, Khan MAH, Lloyd-Jones GC, Evans L, Rotavera B, Huang H, Osborn DL, Mok DKW, Dyke JM, Shallcross DE, Percival CJ, Orr-Ewing AJ, Taatjes CA. Direct Measurements of Unimolecular and Bimolecular Reaction Kinetics of the Criegee Intermediate (CH3)2COO. J Phys Chem A 2016; 121:4-15. [DOI: 10.1021/acs.jpca.6b07810] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rabi Chhantyal-Pun
- School of Chemistry, The University of Bristol, Cantock’s
Close BS8 1TS, U.K
| | - Oliver Welz
- Combustion Research Facility, Mail Stop
9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - John D. Savee
- Combustion Research Facility, Mail Stop
9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Arkke J. Eskola
- Combustion Research Facility, Mail Stop
9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Edmond P. F. Lee
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, U.K
- Department
of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Lucy Blacker
- School of Chemistry, The University of Bristol, Cantock’s
Close BS8 1TS, U.K
| | - Henry R. Hill
- School of Chemistry, The University of Bristol, Cantock’s
Close BS8 1TS, U.K
| | - Matilda Ashcroft
- School of Chemistry, The University of Bristol, Cantock’s
Close BS8 1TS, U.K
| | - M. Anwar H. Khan
- School of Chemistry, The University of Bristol, Cantock’s
Close BS8 1TS, U.K
| | - Guy C. Lloyd-Jones
- School of Chemistry, The University of Bristol, Cantock’s
Close BS8 1TS, U.K
| | - Louise Evans
- School of Chemistry, The University of Bristol, Cantock’s
Close BS8 1TS, U.K
| | - Brandon Rotavera
- Combustion Research Facility, Mail Stop
9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Haifeng Huang
- Combustion Research Facility, Mail Stop
9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - David L. Osborn
- Combustion Research Facility, Mail Stop
9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Daniel K. W. Mok
- The Centre
for Atmospheric Science, The School of Earth, Atmospheric and Environmental
Science, The University of Manchester, Simon Building, Brunswick Street, Manchester M13 9PL, U.K
| | - John M. Dyke
- Department
of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | | | - Carl J. Percival
- The Centre
for Atmospheric Science, The School of Earth, Atmospheric and Environmental
Science, The University of Manchester, Simon Building, Brunswick Street, Manchester M13 9PL, U.K
| | - Andrew J. Orr-Ewing
- School of Chemistry, The University of Bristol, Cantock’s
Close BS8 1TS, U.K
| | - Craig A. Taatjes
- Combustion Research Facility, Mail Stop
9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
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34
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Shallcross DE, Leather KE, Bacak A, Xiao P, Lee EPF, Ng M, Mok DKW, Dyke JM, Hossaini R, Chipperfield MP, Khan MAH, Percival CJ. Reaction between CH3O2 and BrO Radicals: A New Source of Upper Troposphere Lower Stratosphere Hydroxyl Radicals. J Phys Chem A 2015; 119:4618-32. [DOI: 10.1021/jp5108203] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Kimberley E. Leather
- School
of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, U.K
| | - Asan Bacak
- School
of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, U.K
| | - Ping Xiao
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
| | - Edmond P. F. Lee
- School
of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, U.K
- Department
of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Maggie Ng
- Department
of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Daniel K. W. Mok
- Department
of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - John M. Dyke
- School
of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, U.K
| | - Ryan Hossaini
- School
of Earth and Environment, University of Leeds, Leeds LS2 9JT, U.K
| | | | - M. Anwar H. Khan
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
| | - Carl J. Percival
- School
of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, U.K
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Chhantyal-Pun R, Davey A, Shallcross DE, Percival CJ, Orr-Ewing AJ. A kinetic study of the CH2OO Criegee intermediate self-reaction, reaction with SO2 and unimolecular reaction using cavity ring-down spectroscopy. Phys Chem Chem Phys 2015; 17:3617-26. [DOI: 10.1039/c4cp04198d] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A rate coefficient is reported for the CH2OO self-reaction and evidence presented for SO2-catalysed CH2OO isomerization or intersystem crossing.
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Affiliation(s)
| | | | | | - Carl J. Percival
- Centre for Atmospheric Science
- School of Earth
- Atmospheric and Environmental Sciences
- University of Manchester
- Manchester
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36
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Shallcross DE, Taatjes CA, Percival CJ. Criegee intermediates in the indoor environment: new insights. Indoor Air 2014; 24:495-502. [PMID: 24512513 DOI: 10.1111/ina.12102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Accepted: 02/02/2014] [Indexed: 06/03/2023]
Abstract
Criegee intermediates are formed in the ozonolysis of alkenes and play an important role in indoor chemistry, notably as a source of OH radicals. Recent studies have shown that these Criegee intermediates react very quickly with NO2 , SO2 , and carbonyls, and in this study, steady-state calculations are used to inspect the potential impact of these data on indoor chemistry. It is shown that these reactions could accelerate NO3 formation and SO2 removal in the indoor environment significantly. In addition, reaction between Criegee intermediates and halogenated carbonyls could provide a significant loss process indoors, where currently one does not exist.
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Affiliation(s)
- D E Shallcross
- School of Chemistry, Cantock's Close, University of Bristol, Bristol, UK
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37
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38
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Higgins CM, Evans LA, Lloyd-Jones GC, Shallcross DE, Tew DP, Orr-Ewing AJ. Quantum Yields for Photochemical Production of NO2 from Organic Nitrates at Tropospherically Relevant Wavelengths. J Phys Chem A 2014; 118:2756-64. [DOI: 10.1021/jp501517t] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christina M. Higgins
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Louise A. Evans
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Guy C. Lloyd-Jones
- School
of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K
| | - Dudley E. Shallcross
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - David P. Tew
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Andrew J. Orr-Ewing
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
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39
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Welz O, Eskola AJ, Sheps L, Rotavera B, Savee JD, Scheer AM, Osborn DL, Lowe D, Murray Booth A, Xiao P, Anwar H Khan M, Percival CJ, Shallcross DE, Taatjes CA. Rate coefficients of C(1) and C(2) Criegee intermediate reactions with formic and acetic Acid near the collision limit: direct kinetics measurements and atmospheric implications. Angew Chem Int Ed Engl 2014; 53:4547-50. [PMID: 24668781 PMCID: PMC4499262 DOI: 10.1002/anie.201400964] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Indexed: 11/17/2022]
Abstract
Rate coefficients are directly determined for the reactions of the Criegee intermediates (CI) CH2OO and CH3CHOO with the two simplest carboxylic acids, formic acid (HCOOH) and acetic acid (CH3COOH), employing two complementary techniques: multiplexed photoionization mass spectrometry and cavity-enhanced broadband ultraviolet absorption spectroscopy. The measured rate coefficients are in excess of 1×10−10 cm3 s−1, several orders of magnitude larger than those suggested from many previous alkene ozonolysis experiments and assumed in atmospheric modeling studies. These results suggest that the reaction with carboxylic acids is a substantially more important loss process for CIs than is presently assumed. Implementing these rate coefficients in global atmospheric models shows that reactions between CI and organic acids make a substantial contribution to removal of these acids in terrestrial equatorial areas and in other regions where high CI concentrations occur such as high northern latitudes, and implies that sources of acids in these areas are larger than previously recognized.
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Affiliation(s)
- Oliver Welz
- Combustion Research Facility, Sandia National Laboratories, Stop 9055, Livermore, CA 94551-0969 (USA)
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Welz O, Eskola AJ, Sheps L, Rotavera B, Savee JD, Scheer AM, Osborn DL, Lowe D, Murray Booth A, Xiao P, Anwar H. Khan M, Percival CJ, Shallcross DE, Taatjes CA. Rate Coefficients of C1 and C2 Criegee Intermediate Reactions with Formic and Acetic Acid Near the Collision Limit: Direct Kinetics Measurements and Atmospheric Implications. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201400964] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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41
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Copeland G, Lee EPF, Williams RG, Archibald AT, Shallcross DE, Dyke JM. Determination of the photolysis rate coefficient of monochlorodimethyl sulfide (MClDMS) in the atmosphere and its implications for the enhancement of SO2 production from the DMS + Cl2 reaction. Environ Sci Technol 2014; 48:1557-1565. [PMID: 24280000 DOI: 10.1021/es402956r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this work, the photolysis rate coefficient of CH3SCH2Cl (MClDMS) in the lower atmosphere has been determined and has been used in a marine boundary layer (MBL) box model to determine the enhancement of SO2 production arising from the reaction DMS + Cl2. Absorption cross sections measured in the 28000-34000 cm(-1) region have been used to determine photolysis rate coefficients of MClDMS in the troposphere at 10 solar zenith angles (SZAs). These have been used to determine the lifetimes of MClDMS in the troposphere. At 0° SZA, a photolysis lifetime of 3-4 h has been obtained. The results show that the photolysis lifetime of MClDMS is significantly smaller than the lifetimes with respect to reaction with OH (≈ 4.6 days) and with Cl atoms (≈ 1.2 days). It has also been shown, using experimentally derived dissociation energies with supporting quantum-chemical calculations, that the dominant photodissocation route of MClDMS is dissociation of the C-S bond to give CH3S and CH2Cl. MBL box modeling calculations show that buildup of MClDMS at night from the Cl2 + DMS reaction leads to enhanced SO2 production during the day. The extra SO2 arises from photolysis of MClDMS to give CH3S and CH2Cl, followed by subsequent oxidation of CH3S.
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Affiliation(s)
- G Copeland
- School of Chemistry, University of Southampton , Highfield, Southampton SO17 1BJ, U.K
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Taatjes CA, Shallcross DE, Percival CJ. Research frontiers in the chemistry of Criegee intermediates and tropospheric ozonolysis. Phys Chem Chem Phys 2014; 16:1704-18. [DOI: 10.1039/c3cp52842a] [Citation(s) in RCA: 214] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Percival CJ, Welz O, Eskola AJ, Savee JD, Osborn DL, Topping DO, Lowe D, Utembe SR, Bacak A, McFiggans G, Cooke MC, Xiao P, Archibald† AT, Jenkin ME, Derwent RG, Riipinen I, Mok DWK, Lee EPF, Dyke JM, Taatjes CA, Shallcross DE. Regional and global impacts of Criegee intermediates on atmospheric sulphuric acid concentrations and first steps of aerosol formation. Faraday Discuss 2013; 165:45-73. [DOI: 10.1039/c3fd00048f] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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44
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Lee EPF, Mok DKW, Shallcross DE, Percival CJ, Osborn DL, Taatjes CA, Dyke JM. Spectroscopy of the Simplest Criegee Intermediate CH2OO: Simulation of the First Bands in Its Electronic and Photoelectron Spectra. Chemistry 2012; 18:12411-23. [DOI: 10.1002/chem.201200848] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Indexed: 11/11/2022]
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45
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Ghalaieny M, Bacak A, McGillen M, Martin D, Knights AV, O'Doherty S, Shallcross DE, Percival CJ. Determination of gas-phase ozonolysis rate coefficients of a number of sesquiterpenes at elevated temperatures using the relative rate method. Phys Chem Chem Phys 2012; 14:6596-602. [PMID: 22456861 DOI: 10.1039/c2cp23988d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The rates of ozonolysis of four sesquiterpenes, β-caryophyllene, α-humulene, isolongifolene and α-cedrene, are determined in the gas phase at an elevated temperature of 366 ± 3 K and a pressure of ~780 Torr using the EXTreme RAnge chamber (EXTRA). The experimentally obtained rate coefficients agree with extrapolated room temperature rate coefficients for isolongifolene and α-cedrene but not for β-caryophyllene and α-humulene, which were found to be three orders of magnitude slower than this in the literature. These new measurements support the hypothesis that operating under ambient conditions, kinetic measurements of condensable species can be influenced adversely by heterogeneous processes and should therefore be treated with caution.
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Affiliation(s)
- Mohamed Ghalaieny
- Centre for Atmospheric Science, School of Earth Atmospheric and Environmental Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
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Henne S, Shallcross DE, Reimann S, Xiao P, Brunner D, O'Doherty S, Buchmann B. Future emissions and atmospheric fate of HFC-1234yf from mobile air conditioners in Europe. Environ Sci Technol 2012; 46:1650-8. [PMID: 22225403 DOI: 10.1021/es2034608] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
HFC-1234yf (2,3,3,3-tetrafluoropropene) is under discussion for replacing HFC-134a (1,1,1,2-tetrafluoroethane) as a cooling agent in mobile air conditioners (MACs) in the European vehicle fleet. Some HFC-1234yf will be released into the atmosphere, where it is almost completely transformed to the persistent trifluoroacetic acid (TFA). Future emissions of HFC-1234yf after a complete conversion of the European vehicle fleet were assessed. Taking current day leakage rates and predicted vehicle numbers for the year 2020 into account, European total HFC-1234yf emissions from MACs were predicted to range between 11.0 and 19.2 Gg yr(-1). Resulting TFA deposition rates and rainwater concentrations over Europe were assessed with two Lagrangian chemistry transport models. Mean European summer-time TFA mixing ratios of about 0.15 ppt (high emission scenario) will surpass previously measured levels in background air in Germany and Switzerland by more than a factor of 10. Mean deposition rates (wet + dry) of TFA were estimated to be 0.65-0.76 kg km(-2) yr(-1), with a maxium of ∼2.0 kg km(-2) yr(-1) occurring in Northern Italy. About 30-40% of the European HFC-1234yf emissions were deposited as TFA within Europe, while the remaining fraction was exported toward the Atlantic Ocean, Central Asia, Northern, and Tropical Africa. Largest annual mean TFA concentrations in rainwater were simulated over the Mediterranean and Northern Africa, reaching up to 2500 ng L(-1), while maxima over the continent of about 2000 ng L(-1) occurred in the Czech Republic and Southern Germany. These highest annual mean concentrations are at least 60 times lower than previously determined to be a safe level for the most sensitive aquatic life-forms. Rainwater concentrations during individual rain events would still be 1 order of magnitude lower than the no effect level. To verify these results future occasional sampling of TFA in the atmospheric environment should be considered. If future HFC-1234yf emissions surpass amounts used here studies of TFA accumulation in endorheic basins and other sensitive areas should be aspired.
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Affiliation(s)
- Stephan Henne
- Laboratory for Air Pollution/Environmental Technology, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland.
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Leather KE, Bacak A, Wamsley R, Archibald AT, Husk A, Shallcross DE, Percival CJ. Temperature and pressure dependence of the rate coefficient for the reaction between ClO and CH3O2 in the gas-phase. Phys Chem Chem Phys 2012; 14:3425-34. [DOI: 10.1039/c2cp22834c] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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48
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Taatjes CA, Welz O, Eskola AJ, Savee JD, Osborn DL, Lee EPF, Dyke JM, Mok DWK, Shallcross DE, Percival CJ. Direct measurement of Criegee intermediate (CH2OO) reactions with acetone, acetaldehyde, and hexafluoroacetone. Phys Chem Chem Phys 2012; 14:10391-400. [DOI: 10.1039/c2cp40294g] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Harrison TG, Shallcross DE, Norman NC, Sewry JD, Davies-Coleman MT. Publicising chemistry in a multicultural society through chemistry outreach. S AFR J SCI 2011. [DOI: 10.4102/sajs.v107i11/12.669] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Khan MAH, Hoque MMN, Alam SS, Ashfold MJ, Nickless G, Shallcross DE. Estimation and comparison of night-time OH levels in the UK urban atmosphere using two different analysis methods. J Environ Sci (China) 2011; 23:60-64. [PMID: 21476341 DOI: 10.1016/s1001-0742(10)60373-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Night-time OH levels have been determined for UK urban surface environments using two methods, the decay and steady state approximation methods. Measurement data from the UK National Environmental Technology Centre archive for four urban sites (Bristol, Harwell, London Eltham and Edinburgh) over the time period of 1996 to 2000 have been used in this study. Three reactive alkenes, namely isoprene, 1,3-butadiene and trans-2-pentene were chosen for the calculation of OH levels by the decay method. Hourly measurements of NO, NO2, O3, CO and 20 VOCs were used to determine night-time OH level using the steady state approximation method. Our results showed that the night-time OH levels were in the range of 1 x 10(5) - 1 x 10(6) molecules/cm3 at these four urban sites in the UK. The application of a t-test of these analyses indicated that except Bristol, there was no significant difference between the OH levels found from the decay and steady state approximation methods. Night-time levels of the OH radical appeared to peak in summer and spring time tracking the night-time O3 levels which also passed through a maximum at this time.
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Affiliation(s)
- M Anwar H Khan
- School of Chemistry, University of Bristol, BS8 1TS, United Kingdom.
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