Articles | Volume 13, issue 2
https://doi.org/10.5194/amt-13-839-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/amt-13-839-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
20 Feb 2020
Research article |
| 20 Feb 2020
A new instrument for time-resolved measurement of HO2 radicals
Thomas H. Speak
School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
Mark A. Blitz
School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
National Centre for Atmospheric Science, University of Leeds, Leeds, LS2 9JT, UK
Daniel Stone
School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
National Centre for Atmospheric Science, University of Leeds, Leeds, LS2 9JT, UK
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Frank A. F. Winiberg, William J. Warman, Charlotte A. Brumby, Graham Boustead, Iustinian G. Bejan, Thomas H. Speak, Dwayne E. Heard, Daniel Stone, and Paul W. Seakins
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2023-123, https://doi.org/10.5194/amt-2023-123, 2023
Revised manuscript accepted for AMT
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OH and HO2 are key reactive intermediates in the Earth's atmosphere. Accurate measurements in either the field or in simulation chambers provide a good test for chemical mechanisms. Fluorescence techniques have the appropriate sensitivity for detection but require calibration. This paper compares different methods of calibration and specifically how calibration factors vary across a temperature range relevant to atmospheric and chamber determinations.
Zara S. Mir, Matthew Jamieson, Nicholas R. Greenall, Paul W. Seakins, Mark A. Blitz, and Daniel Stone
Atmos. Meas. Tech., 15, 2875–2887, https://doi.org/10.5194/amt-15-2875-2022, https://doi.org/10.5194/amt-15-2875-2022, 2022
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In this work we describe the development and characterisation of an experiment using laser flash photolysis coupled with time-resolved mid-infrared (mid-IR) quantum cascade laser (QCL) absorption spectroscopy, with initial results reported for measurements of the infrared spectrum, kinetics, and product yields for the reaction of the CH2OO Criegee intermediate with SO2. This work has significance for the identification and measurement of reactive trace species in complex systems.
Hannah Walker, Daniel Stone, Trevor Ingham, Sina Hackenberg, Danny Cryer, Shalini Punjabi, Katie Read, James Lee, Lisa Whalley, Dominick V. Spracklen, Lucy J. Carpenter, Steve R. Arnold, and Dwayne E. Heard
Atmos. Chem. Phys., 22, 5535–5557, https://doi.org/10.5194/acp-22-5535-2022, https://doi.org/10.5194/acp-22-5535-2022, 2022
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Glyoxal is a ubiquitous reactive organic compound in the atmosphere, which may form organic aerosol and impact the atmosphere's oxidising capacity. There are limited measurements of glyoxal's abundance in the remote marine atmosphere. We made new measurements of glyoxal using a highly sensitive technique over two 4-week periods in the tropical Atlantic atmosphere. We show that daytime measurements are mostly consistent with our chemical understanding but a potential missing source at night.
Esther Borrás, Luis A. Tortajada-Genaro, Milagro Ródenas, Teresa Vera, Thomas Speak, Paul Seakins, Marvin D. Shaw, Alastair C. Lewis, and Amalia Muñoz
Atmos. Meas. Tech., 14, 4989–4999, https://doi.org/10.5194/amt-14-4989-2021, https://doi.org/10.5194/amt-14-4989-2021, 2021
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This work presents promising results in the characterization of specific atmospheric pollutants (oxygenated VOCs) present at very low but highly relevant concentrations.
We carried out this research at EUPHORE facilities within the framework of the EUROCHAMP project. A new analytical method, with high robustness and precision, also clean in the use of solvents, low cost, and easily adaptable for use in mobile laboratories for air quality monitoring, is presented.
Joanna E. Dyson, Graham A. Boustead, Lauren T. Fleming, Mark Blitz, Daniel Stone, Stephen R. Arnold, Lisa K. Whalley, and Dwayne E. Heard
Atmos. Chem. Phys., 21, 5755–5775, https://doi.org/10.5194/acp-21-5755-2021, https://doi.org/10.5194/acp-21-5755-2021, 2021
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The hydroxyl radical (OH) dominates the removal of atmospheric pollutants, with nitrous acid (HONO) recognised as a major OH source. For remote regions HONO production through the action of sunlight on aerosol surfaces can provide a source of nitrogen oxides. In this study, HONO production rates at illuminated aerosol surfaces are measured under atmospheric conditions, a model consistent with the data is developed and aerosol production of HONO in the atmosphere is shown to be significant.
Thomas R. Lewis, Juan Carlos Gómez Martín, Mark A. Blitz, Carlos A. Cuevas, John M. C. Plane, and Alfonso Saiz-Lopez
Atmos. Chem. Phys., 20, 10865–10887, https://doi.org/10.5194/acp-20-10865-2020, https://doi.org/10.5194/acp-20-10865-2020, 2020
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Iodine-bearing gasses emitted from the sea surface are chemically processed in the atmosphere, leading to iodine accumulation in aerosol and transport to continental ecosystems. Such processing involves light-induced break-up of large, particle-forming iodine oxides into smaller, ozone-depleting molecules. We combine experiments and theory to report the photolysis efficiency of iodine oxides required to assess the impact of iodine on ozone depletion and particle formation.
Robert Woodward-Massey, Eloise J. Slater, Jake Alen, Trevor Ingham, Danny R. Cryer, Leanne M. Stimpson, Chunxiang Ye, Paul W. Seakins, Lisa K. Whalley, and Dwayne E. Heard
Atmos. Meas. Tech., 13, 3119–3146, https://doi.org/10.5194/amt-13-3119-2020, https://doi.org/10.5194/amt-13-3119-2020, 2020
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The OH radical is known as nature’s detergent, removing most trace gases from the atmosphere. Hence, an accurate measurement of its concentration is very important. We present measurements of OH in several field locations using a laser-based fluorescence method equipped with an OH scavenger. By determining the background signal in two different ways, we show that the instrument does not suffer any significant interferences that could result in an overestimation of OH concentrations.
Lavinia Onel, Alexander Brennan, Michele Gianella, James Hooper, Nicole Ng, Gus Hancock, Lisa Whalley, Paul W. Seakins, Grant A. D. Ritchie, and Dwayne E. Heard
Atmos. Meas. Tech., 13, 2441–2456, https://doi.org/10.5194/amt-13-2441-2020, https://doi.org/10.5194/amt-13-2441-2020, 2020
Daniel Stone, Tomás Sherwen, Mathew J. Evans, Stewart Vaughan, Trevor Ingham, Lisa K. Whalley, Peter M. Edwards, Katie A. Read, James D. Lee, Sarah J. Moller, Lucy J. Carpenter, Alastair C. Lewis, and Dwayne E. Heard
Atmos. Chem. Phys., 18, 3541–3561, https://doi.org/10.5194/acp-18-3541-2018, https://doi.org/10.5194/acp-18-3541-2018, 2018
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Halogen chemistry in the troposphere impacts oxidising capacity, but model studies assessing the nature of these impacts can vary according to the model framework used. In this work we present simulations of OH and HO2 radicals using both box and global model frameworks, and compare to observations made at the Cape Verde Atmospheric Observatory. We highlight, and rationalise, differences between the model frameworks.
Lisa K. Whalley, Daniel Stone, Rachel Dunmore, Jacqueline Hamilton, James R. Hopkins, James D. Lee, Alastair C. Lewis, Paul Williams, Jörg Kleffmann, Sebastian Laufs, Robert Woodward-Massey, and Dwayne E. Heard
Atmos. Chem. Phys., 18, 2547–2571, https://doi.org/10.5194/acp-18-2547-2018, https://doi.org/10.5194/acp-18-2547-2018, 2018
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This paper presents the first radical observations made in London and subsequent model comparisons. This work highlights that there are uncertainties in the degradation mechanism of complex biogenic and diesel-related VOC species under low-NOx conditions and under high-NOx conditions there is a missing source of RO2 radicals. The impact of these model uncertainties on in situ ozone production as a function of NOx is discussed.
Daniel R. Moon, Giorgio S. Taverna, Clara Anduix-Canto, Trevor Ingham, Martyn P. Chipperfield, Paul W. Seakins, Maria-Teresa Baeza-Romero, and Dwayne E. Heard
Atmos. Chem. Phys., 18, 327–338, https://doi.org/10.5194/acp-18-327-2018, https://doi.org/10.5194/acp-18-327-2018, 2018
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One geoengineering mitigation strategy for global temperature rises is to inject particles into the stratosphere to scatter solar radiation back to space. However, the injection of such particles must not perturb ozone. We measured the rate of uptake of HO2 radicals, an important stratospheric intermediate, onto TiO2 particles. Using the atmospheric model TOMCAT, we showed that surface reactions between HO2 and TiO2 would have a negligible effect on stratospheric concentrations of HO2 and ozone.
Lavinia Onel, Alexander Brennan, Michele Gianella, Grace Ronnie, Ana Lawry Aguila, Gus Hancock, Lisa Whalley, Paul W. Seakins, Grant A. D. Ritchie, and Dwayne E. Heard
Atmos. Meas. Tech., 10, 4877–4894, https://doi.org/10.5194/amt-10-4877-2017, https://doi.org/10.5194/amt-10-4877-2017, 2017
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Hydroperoxy (HO2) radicals are key intermediates participating in a rapid chemical cycling at the centre of the tropospheric oxidation. Fluorescence assay by gas expansion (FAGE) technique is the most commonly used for the HO2 measurements in the atmosphere. However, FAGE is an indirect technique, requiring calibration. This work finds a good agreement between the indirect FAGE method and the direct cavity ring-down spectroscopy method and hence validates FAGE and the FAGE calibration method.
Lavinia Onel, Alexander Brennan, Paul W. Seakins, Lisa Whalley, and Dwayne E. Heard
Atmos. Meas. Tech., 10, 3985–4000, https://doi.org/10.5194/amt-10-3985-2017, https://doi.org/10.5194/amt-10-3985-2017, 2017
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Methyl peroxy (CH3O2) radicals are the most abundant organic peroxy radical species and are critical intermediates in rapid chemical cycling at the heart of tropospheric oxidation. Despite their importance, at present CH3O2 radicals are not specifically measured in the atmosphere by any direct or indirect method. This work presents a new method for the selective and sensitive detection of CH3O2 radicals and its use for the measurement of CH3O2 in the atmospheric simulation chamber HIRAC.
Hendrik Fuchs, Anna Novelli, Michael Rolletter, Andreas Hofzumahaus, Eva Y. Pfannerstill, Stephan Kessel, Achim Edtbauer, Jonathan Williams, Vincent Michoud, Sebastien Dusanter, Nadine Locoge, Nora Zannoni, Valerie Gros, Francois Truong, Roland Sarda-Esteve, Danny R. Cryer, Charlotte A. Brumby, Lisa K. Whalley, Daniel Stone, Paul W. Seakins, Dwayne E. Heard, Coralie Schoemaecker, Marion Blocquet, Sebastien Coudert, Sebastien Batut, Christa Fittschen, Alexander B. Thames, William H. Brune, Cheryl Ernest, Hartwig Harder, Jennifer B. A. Muller, Thomas Elste, Dagmar Kubistin, Stefanie Andres, Birger Bohn, Thorsten Hohaus, Frank Holland, Xin Li, Franz Rohrer, Astrid Kiendler-Scharr, Ralf Tillmann, Robert Wegener, Zhujun Yu, Qi Zou, and Andreas Wahner
Atmos. Meas. Tech., 10, 4023–4053, https://doi.org/10.5194/amt-10-4023-2017, https://doi.org/10.5194/amt-10-4023-2017, 2017
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Hydroxyl radical reactivity (k(OH)) is closely related to processes that lead to the formation of oxidised, secondary pollutants such as ozone and aerosol. In order to compare the performances of instruments measuring k(OH), experiments were conducted in the simulation chamber SAPHIR. Chemical conditions were chosen either to be representative of the atmosphere or to test potential limitations of instruments. Overall, the results show that instruments are capable of measuring k(OH).
Daniel Stone, Lisa K. Whalley, Trevor Ingham, Peter M. Edwards, Danny R. Cryer, Charlotte A. Brumby, Paul W. Seakins, and Dwayne E. Heard
Atmos. Meas. Tech., 9, 2827–2844, https://doi.org/10.5194/amt-9-2827-2016, https://doi.org/10.5194/amt-9-2827-2016, 2016
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OH reactivity is the total pseudo-first-order loss rate coefficient describing the removal of OH radicals to all sinks in the atmosphere. Measurements of ambient OH reactivity can be used to discover the extent to which measured OH sinks contribute to the total OH loss rate. In this work, we describe the design and characterisation of an instrument to measure OH reactivity using laser flash photolysis coupled to laser-induced fluorescence (LFP-LIF) spectroscopy.
Chris Reed, Charlotte A. Brumby, Leigh R. Crilley, Louisa J. Kramer, William J. Bloss, Paul W. Seakins, James D. Lee, and Lucy J. Carpenter
Atmos. Meas. Tech., 9, 2483–2495, https://doi.org/10.5194/amt-9-2483-2016, https://doi.org/10.5194/amt-9-2483-2016, 2016
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A new method of measuring nitrous acid (HONO), a potent mediator of air quality in the atmosphere as well as an important indoor pollutant, is presented. The new method relies on simple, proven techniques already widely applied to other atmospheric compounds. The technique can be retrofitted to existing analysers at minimal cost, or developed into instruments capable of very fast measurement which allow for more complex analysis of the behaviour of HONO.
Frank A. F. Winiberg, Terry J. Dillon, Stephanie C. Orr, Christoph B. M Groß, Iustinian Bejan, Charlotte A. Brumby, Matthew J. Evans, Shona C. Smith, Dwayne E. Heard, and Paul W. Seakins
Atmos. Chem. Phys., 16, 4023–4042, https://doi.org/10.5194/acp-16-4023-2016, https://doi.org/10.5194/acp-16-4023-2016, 2016
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OH radicals are important intermediates in the atmosphere, and the high concentrations observed in tropical regions are yet to be fully explained. Radical-radical reactions such as the title reaction can contribute to OH formation. This is the most fully comprehensive study of the CH3C(O)O2 + HO2 reaction with direct observation of products in all reaction channels. The implications of the new measurements on OH, PAN and NOx concentrations are considered via global models.
J. D. Lee, L. K. Whalley, D. E. Heard, D. Stone, R. E. Dunmore, J. F. Hamilton, D. E. Young, J. D. Allan, S. Laufs, and J. Kleffmann
Atmos. Chem. Phys., 16, 2747–2764, https://doi.org/10.5194/acp-16-2747-2016, https://doi.org/10.5194/acp-16-2747-2016, 2016
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This paper presents field measurements of HONO and a range of other gas phase and particulate species from an urban background site in London. The measured daytime HONO cannot be reproduced with a simple box model and thus a significant daytime missing source of HONO is present. We show that this missing source could be responsible for 40 % of the OH radical source and 57 % of the OH initiation; hence its potential importance for atmospheric oxidation and ozone production.
Lisa K. Whalley, Daniel Stone, Brian Bandy, Rachel Dunmore, Jacqueline F. Hamilton, James Hopkins, James D. Lee, Alastair C. Lewis, and Dwayne E. Heard
Atmos. Chem. Phys., 16, 2109–2122, https://doi.org/10.5194/acp-16-2109-2016, https://doi.org/10.5194/acp-16-2109-2016, 2016
H. M. Walker, D. Stone, T. Ingham, S. Vaughan, M. Cain, R. L. Jones, O. J. Kennedy, M. McLeod, B. Ouyang, J. Pyle, S. Bauguitte, B. Bandy, G. Forster, M. J. Evans, J. F. Hamilton, J. R. Hopkins, J. D. Lee, A. C. Lewis, R. T. Lidster, S. Punjabi, W. T. Morgan, and D. E. Heard
Atmos. Chem. Phys., 15, 8179–8200, https://doi.org/10.5194/acp-15-8179-2015, https://doi.org/10.5194/acp-15-8179-2015, 2015
L. K. Whalley, D. Stone, I. J. George, S. Mertes, D. van Pinxteren, A. Tilgner, H. Herrmann, M. J. Evans, and D. E. Heard
Atmos. Chem. Phys., 15, 3289–3301, https://doi.org/10.5194/acp-15-3289-2015, https://doi.org/10.5194/acp-15-3289-2015, 2015
F. A. F. Winiberg, S. C. Smith, I. Bejan, C. A. Brumby, T. Ingham, T. L. Malkin, S. C. Orr, D. E. Heard, and P. W. Seakins
Atmos. Meas. Tech., 8, 523–540, https://doi.org/10.5194/amt-8-523-2015, https://doi.org/10.5194/amt-8-523-2015, 2015
D. Stone, M. J. Evans, H. Walker, T. Ingham, S. Vaughan, B. Ouyang, O. J. Kennedy, M. W. McLeod, R. L. Jones, J. Hopkins, S. Punjabi, R. Lidster, J. F. Hamilton, J. D. Lee, A. C. Lewis, L. J. Carpenter, G. Forster, D. E. Oram, C. E. Reeves, S. Bauguitte, W. Morgan, H. Coe, E. Aruffo, C. Dari-Salisburgo, F. Giammaria, P. Di Carlo, and D. E. Heard
Atmos. Chem. Phys., 14, 1299–1321, https://doi.org/10.5194/acp-14-1299-2014, https://doi.org/10.5194/acp-14-1299-2014, 2014
L. K. Whalley, M. A. Blitz, M. Desservettaz, P. W. Seakins, and D. E. Heard
Atmos. Meas. Tech., 6, 3425–3440, https://doi.org/10.5194/amt-6-3425-2013, https://doi.org/10.5194/amt-6-3425-2013, 2013
P. M. Edwards, M. J. Evans, K. L. Furneaux, J. Hopkins, T. Ingham, C. Jones, J. D. Lee, A. C. Lewis, S. J. Moller, D. Stone, L. K. Whalley, and D. E. Heard
Atmos. Chem. Phys., 13, 9497–9514, https://doi.org/10.5194/acp-13-9497-2013, https://doi.org/10.5194/acp-13-9497-2013, 2013
Related subject area
Subject: Gases | Technique: Laboratory Measurement | Topic: Instruments and Platforms
Characterizing the automatic radon flux transfer standard system Autoflux: laboratory calibration and field experiments
A Novel Inlet for Enriching Concentrations of Reactive Organic Gases in Low Sampling Flows
Revision of an open-split-based dual inlet system for elemental and isotope ratio mass spectrometers with a focus on clumped isotope measurements
Influence of ozone and humidity on PTR-MS and GC-MS VOC measurements with and without a Na2S2O3 ozone scrubber
Characterisation of the multi-scheme chemical ionisation inlet-2 and the detection of gaseous iodine species
Laser-induced sublimation extraction for centimeter-resolution multi-species greenhouse gas analysis on ice cores
Ozone reactivity measurement of biogenic volatile organic compound emissions
Comparison of two photolytic calibration methods for nitrous acid
Measurement of enantiomer percentages for five monoterpenes from six conifer species by cartridge-tube-based passive sampling adsorption–thermal desorption (ps-ATD)
Identification, monitoring, and reaction kinetics of reactive trace species using time-resolved mid-infrared quantum cascade laser absorption spectroscopy: development, characterisation, and initial results for the CH2OO Criegee intermediate
Air pollution monitoring: development of ammonia (NH3) dynamic reference gas mixtures at nanomoles per mole levels to improve the lack of traceability of measurements
Formaldehyde and glyoxal measurement deploying a selected ion flow tube mass spectrometer (SIFT-MS)
Fragmentation inside proton-transfer-reaction-based mass spectrometers limits the detection of ROOR and ROOH peroxides
MULTICHARME: a modified Chernin-type multi-pass cell designed for IR and THz long-path absorption measurements in the CHARME atmospheric simulation chamber
Silicone tube humidity generator
A source for the continuous generation of pure and quantifiable HONO mixtures
Photochemical method for removing methane interference for improved gas analysis
A simulation chamber for absorption spectroscopy in planetary atmospheres
An automated system for trace gas flux measurements from plant foliage and other plant compartments
Simultaneous measurement of δ13C, δ18O and δ17O of atmospheric CO2 – performance assessment of a dual-laser absorption spectrometer
Measurement of iodine species and sulfuric acid using bromide chemical ionization mass spectrometers
A method for resolving changes in atmospheric He ∕ N2 as an indicator of fossil fuel extraction and stratospheric circulation
Application of chemical derivatization techniques combined with chemical ionization mass spectrometry to detect stabilized Criegee intermediates and peroxy radicals in the gas phase
Atomic emission detector with gas chromatographic separation and cryogenic pre-concentration (CryoTrap–GC–AED) for atmospheric trace gas measurements
New technique for high-precision, simultaneous measurements of CH4, N2O and CO2 concentrations; isotopic and elemental ratios of N2, O2 and Ar; and total air content in ice cores by wet extraction
High-precision laser spectrometer for multiple greenhouse gas analysis in 1 mL air from ice core samples
A thermal-dissociation–cavity ring-down spectrometer (TD-CRDS) for the detection of organic nitrates in gas and particle phases
Interference from alkenes in chemiluminescent NOx measurements
Calibration of an airborne HOx instrument using the All Pressure Altitude-based Calibrator for HOx Experimentation (APACHE)
Measurement of ammonia, amines and iodine compounds using protonated water cluster chemical ionization mass spectrometry
An instrument for in situ measurement of total ozone reactivity
Portable calibrator for NO based on the photolysis of N2O and a combined NO2∕NO∕O3 source for field calibrations of air pollution monitors
Investigation of adsorption and desorption behavior of small-volume cylinders and its relevance for atmospheric trace gas analysis
Towards an understanding of surface effects: testing of various materials in a small volume measurement chamber and its relevance for atmospheric trace gas analysis
Stability of halocarbons in air samples stored in stainless- steel canisters
High-precision atmospheric oxygen measurement comparisons between a newly built CRDS analyzer and existing measurement techniques
Characterisation of the transfer of cluster ions through an atmospheric pressure interface time-of-flight mass spectrometer with hexapole ion guides
Addition of fast gas chromatography to selected ion flow tube mass spectrometry for analysis of individual monoterpenes in mixtures
Measurements of delays of gas-phase compounds in a wide variety of tubing materials due to gas–wall interactions
Effects of gas–wall interactions on measurements of semivolatile compounds and small polar molecules
Characterization of a commercial lower-cost medium-precision non-dispersive infrared sensor for atmospheric CO2 monitoring in urban areas
Evaluating the performance of five different chemical ionization techniques for detecting gaseous oxygenated organic species
Cavity-enhanced photoacoustic sensor based on a whispering-gallery-mode diode laser
Using collision-induced dissociation to constrain sensitivity of ammonia chemical ionization mass spectrometry (NH4+ CIMS) to oxygenated volatile organic compounds
A broadband cavity-enhanced spectrometer for atmospheric trace gas measurements and Rayleigh scattering cross sections in the cyan region (470–540 nm)
Large-volume air sample system for measuring 34S∕32S isotope ratio of carbonyl sulfide
New and improved infrared absorption cross sections for trichlorofluoromethane (CFC-11)
Experiments with CO2-in-air reference gases in high-pressure aluminum cylinders
Preflight calibration of the Chinese Environmental Trace Gases Monitoring Instrument (EMI)
Production of highly oxygenated organic molecules (HOMs) from trace contaminants during isoprene oxidation
Claudia Grossi, Daniel Rabago, Scott Chambers, Carlos Sáinz, Roger Curcoll, Peter P. S. Otáhal, Eliška Fialová, Luis Quindos, and Arturo Vargas
Atmos. Meas. Tech., 16, 2655–2672, https://doi.org/10.5194/amt-16-2655-2023, https://doi.org/10.5194/amt-16-2655-2023, 2023
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The automatic and low-maintenance radon flux system Autoflux, completed with environmental soil and atmosphere sensors, has been theoretically and experimentally characterized and calibrated under laboratory conditions to be used as transfer standard for in situ measurements. It will offer for the first time long-term measurements to validate radon flux maps used by the climate and the radiation protection communities for assessing the radon gas emissions in the atmosphere.
Namrata Shanmukh Panji and Gabriel Isaacman-VanWertz
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2023-102, https://doi.org/10.5194/amt-2023-102, 2023
Revised manuscript accepted for AMT
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Measuring volatile organic compounds (VOCs) in the atmosphere is crucial for understanding air quality and environmental impact. Since these compounds are present in low concentrations, preconcentration of samples is often necessary for accurate detection. To address this issue, we have developed a novel inlet that uses selective permeation to concentrate organic gases in small sample flows. This device offers a promising approach for accurately detecting low levels of VOCs in the atmosphere.
Stephan Räss, Peter Nyfeler, Paul Wheeler, Will Price, and Markus Christian Leuenberger
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2023-96, https://doi.org/10.5194/amt-2023-96, 2023
Revised manuscript accepted for AMT
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Due to technological advances clumped isotope studies have gained importance in recent years. Typically, these studies are performed with high resolution isotope ratio mass spectrometers (IRMS) along with a changeover-valve-based dual inlet system (DIS). We are taking a different approach, namely performing clumped isotope measurements with a compact low-resolution IRMS with an open-split-based DIS. Currently, we are working with pure oxygen gas for which we are providing a proof of concept.
Lisa Ernle, Monika Akima Ringsdorf, and Jonathan Williams
Atmos. Meas. Tech., 16, 1179–1194, https://doi.org/10.5194/amt-16-1179-2023, https://doi.org/10.5194/amt-16-1179-2023, 2023
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Atmospheric ozone can induce artefacts in volatile organic compound measurements. Laboratory tests were made using GC-MS and PTR-MS aircraft systems under tropospheric and stratospheric conditions of humidity and ozone, with and without sodium thiosulfate filter scrubbers. Ozone in dry air produces some carbonyls and degrades alkenes. The scrubber lifetime depends on ozone concentration, flow rate and humidity. For the troposphere with scrubber, no significant artefacts were found over 14 d.
Xu-Cheng He, Jiali Shen, Siddharth Iyer, Paxton Juuti, Jiangyi Zhang, Mrisha Koirala, Mikko M. Kytökari, Douglas R. Worsnop, Matti Rissanen, Markku Kulmala, Norbert M. Maier, Jyri Mikkilä, Mikko Sipilä, and Juha Kangasluoma
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2023-30, https://doi.org/10.5194/amt-2023-30, 2023
Revised manuscript accepted for AMT
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In this study, the upgraded multi-scheme chemical ionisation inlet 2 is presented. Sulfuric acid, hypoiodous acid, iodine, sulfur dioxide and hydroperoxyl radical were calibrated and the improved ion optics enable to detect sulfuric acid and iodine-containing molecules at as low as a few parts per quadrillion by volume. Additionally, we confirm in this study that iodic acid is reliably detected by both the nitrate and bromide chemical ionisation methods at atmospherically relevant conditions.
Lars Mächler, Daniel Baggenstos, Florian Krauss, Jochen Schmitt, Bernhard Bereiter, Remo Walther, Christoph Reinhard, Béla Tuzson, Lukas Emmenegger, and Hubertus Fischer
Atmos. Meas. Tech., 16, 355–372, https://doi.org/10.5194/amt-16-355-2023, https://doi.org/10.5194/amt-16-355-2023, 2023
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We present a new method to extract the gases from ice cores and measure their greenhouse gas composition. The ice is sublimated continuously with a near-infrared laser, releasing the gases, which are then analyzed on a laser absorption spectrometer. The main advantage over previous efforts is a low effective resolution of 1–2 cm. This capability is crucial for the analysis of highly thinned ice, as expected from ongoing drilling efforts to extend ice core history further back in time.
Detlev Helmig, Alex Guenther, Jacques Hueber, Ryan Daly, Wei Wang, Jeong-Hoo Park, Anssi Liikanen, and Arnaud P. Praplan
Atmos. Meas. Tech., 15, 5439–5454, https://doi.org/10.5194/amt-15-5439-2022, https://doi.org/10.5194/amt-15-5439-2022, 2022
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This research demonstrates a new method for determination of the chemical reactivity of volatile organic compounds that are emitted from the leaves and needles of trees. These measurements allow elucidating if and how much of these emissions and their associated reactivity are captured and quantified by currently applicable chemical analysis methods.
Andrew J. Lindsay and Ezra C. Wood
Atmos. Meas. Tech., 15, 5455–5464, https://doi.org/10.5194/amt-15-5455-2022, https://doi.org/10.5194/amt-15-5455-2022, 2022
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Nitrous acid (HONO) is an important source of the main atmospheric oxidant – the hydroxyl radical (OH). Advances in nitrous acid measurement techniques and calibration methods therefore improve our understanding of atmospheric oxidation processes. In this paper, we present two calibration methods based on photo-dissociating water vapor. These calibration methods are useful alternatives to conventional calibrations that involve a reacting hydrogen chloride vapor with sodium nitrite.
Ying Wang, Wentai Luo, Todd N. Rosenstiel, and James F. Pankow
Atmos. Meas. Tech., 15, 4651–4661, https://doi.org/10.5194/amt-15-4651-2022, https://doi.org/10.5194/amt-15-4651-2022, 2022
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A rapid, sensitive, and precise analytical method was developed for measuring the fractional amounts of the (−) and (+) forms of chiral enantiomeric forms of monoterpenes in air containing biogenic plant emissions. The method uses passive air sampling onto adsorption–thermal desorption (ATD) gas sampling cartridge tubes; this is followed by automatable thermal desorption onto a chiral gas chromatography (GC) column, followed by detection with mass spectrometry (MS).
Zara S. Mir, Matthew Jamieson, Nicholas R. Greenall, Paul W. Seakins, Mark A. Blitz, and Daniel Stone
Atmos. Meas. Tech., 15, 2875–2887, https://doi.org/10.5194/amt-15-2875-2022, https://doi.org/10.5194/amt-15-2875-2022, 2022
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In this work we describe the development and characterisation of an experiment using laser flash photolysis coupled with time-resolved mid-infrared (mid-IR) quantum cascade laser (QCL) absorption spectroscopy, with initial results reported for measurements of the infrared spectrum, kinetics, and product yields for the reaction of the CH2OO Criegee intermediate with SO2. This work has significance for the identification and measurement of reactive trace species in complex systems.
Tatiana Macé, Maitane Iturrate-Garcia, Céline Pascale, Bernhard Niederhauser, Sophie Vaslin-Reimann, and Christophe Sutour
Atmos. Meas. Tech., 15, 2703–2718, https://doi.org/10.5194/amt-15-2703-2022, https://doi.org/10.5194/amt-15-2703-2022, 2022
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LNE developed, with the company 2M PROCESS, a gas reference generator to dynamically generate NH3 reference gas mixtures in the air at very low fractions between 1 and 400 nmol/mol. The procedure defined by LNE for calibrating NH3 analyzers used for monitoring air quality guarantees relative expanded uncertainties lower than 2 % for this measurement range. The results of a comparison organized between METAS and LNE allowed the validation of LNE's reference generator and calibration procedure.
Antonia G. Zogka, Manolis N. Romanias, and Frederic Thevenet
Atmos. Meas. Tech., 15, 2001–2019, https://doi.org/10.5194/amt-15-2001-2022, https://doi.org/10.5194/amt-15-2001-2022, 2022
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We emphasize the application of SIFT-MS to detect two important atmospheric pollutants, i.e., formaldehyde (FM) and glyoxal (GL). FM and GL are secondary products formed by volatile organic compound oxidation in indoor and outdoor environments and play a key role in air quality and climate. We show that SIFT-MS is able to monitor these species selectively and in real time, overcoming the limitations of other, classical analytical techniques used to monitor these species in the atmosphere.
Haiyan Li, Thomas Golin Almeida, Yuanyuan Luo, Jian Zhao, Brett B. Palm, Christopher D. Daub, Wei Huang, Claudia Mohr, Jordan E. Krechmer, Theo Kurtén, and Mikael Ehn
Atmos. Meas. Tech., 15, 1811–1827, https://doi.org/10.5194/amt-15-1811-2022, https://doi.org/10.5194/amt-15-1811-2022, 2022
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This work evaluated the potential for PTR-based mass spectrometers to detect ROOR and ROOH peroxides both experimentally and through computations. Laboratory experiments using a Vocus PTR observed only noisy signals of potential dimers during α-pinene ozonolysis and a few small signals of dimeric compounds during cyclohexene ozonolysis. Quantum chemical calculations for model ROOR and ROOH systems showed that most of these peroxides should fragment partially following protonation.
Jean Decker, Éric Fertein, Jonas Bruckhuisen, Nicolas Houzel, Pierre Kulinski, Bo Fang, Weixiong Zhao, Francis Hindle, Guillaume Dhont, Robin Bocquet, Gaël Mouret, Cécile Coeur, and Arnaud Cuisset
Atmos. Meas. Tech., 15, 1201–1215, https://doi.org/10.5194/amt-15-1201-2022, https://doi.org/10.5194/amt-15-1201-2022, 2022
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We present a multiple pass system developed for the CHamber for Atmospheric Reactivity and Metrology of the Environment. This multi-pass cell allows monitoring of atmospheric species at trace levels by high-resolution spectroscopy with long interaction path lengths in the IR and for the first time in the terahertz range. Interesting prospects are highlighted in this frequency domain, such as a high degree of selectivity or the possibility to monitor in real-time atmospheric processes.
Robert F. Berg, Nicola Chiodo, and Eric Georgin
Atmos. Meas. Tech., 15, 819–832, https://doi.org/10.5194/amt-15-819-2022, https://doi.org/10.5194/amt-15-819-2022, 2022
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We made a humidity generator that adds water vapor to a flowing gas. Its range of humidity is useful for calibrating balloon-borne probes to the Earth's stratosphere. The generator’s novel feature is a saturator that comprises 5 m of silicone tubing immersed in water. The length was enough to ensure that the saturator’s output was independent of the dimensions and permeability of the tube. This simple, low-cost design provides an accuracy that is acceptable for many applications.
Guillermo Villena and Jörg Kleffmann
Atmos. Meas. Tech., 15, 627–637, https://doi.org/10.5194/amt-15-627-2022, https://doi.org/10.5194/amt-15-627-2022, 2022
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A continuous source for the generation of pure HONO mixtures was developed and characterized, which is based on the Henry's law solubility of HONO in acidic aqueous solutions. The source shows a fast time response and an excellent long-term stability and can be easily adjusted to HONO mixing ratios in the range 0.05–500 ppb. A general equation based on Henry's law is developed, whereby the HONO concentration of the source can be absolutely calculated with an accuracy of better than 10 %.
Merve Polat, Jesper Baldtzer Liisberg, Morten Krogsbøll, Thomas Blunier, and Matthew S. Johnson
Atmos. Meas. Tech., 14, 8041–8067, https://doi.org/10.5194/amt-14-8041-2021, https://doi.org/10.5194/amt-14-8041-2021, 2021
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We have designed a process for removing methane from a gas stream so that nitrous oxide can be measured without interference. These are both key long-lived greenhouse gases frequently studied in relation to ice cores, plants, water treatment and so on. However, many researchers are not aware of the problem of methane interference, and in addition there have not been good methods available for solving the problem. Here we present and evaluate such a method.
Marcel Snels, Stefania Stefani, Angelo Boccaccini, David Biondi, and Giuseppe Piccioni
Atmos. Meas. Tech., 14, 7187–7197, https://doi.org/10.5194/amt-14-7187-2021, https://doi.org/10.5194/amt-14-7187-2021, 2021
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A novel simulation chamber, PASSxS (Planetary Atmosphere Simulation System for Spectroscopy), has been developed for absorption measurements with a Fourier transform spectrometer (FTS) and possibly a cavity ring-down (CRD) spectrometer, with a sample temperature ranging from 100 K up to 550 K, while the pressure of the gas can be varied up to 60 bar. These temperature and pressure ranges cover a significant part of the planetary atmospheres in the solar system and possibly extrasolar planets.
Lukas Kohl, Markku Koskinen, Tatu Polvinen, Salla Tenhovirta, Kaisa Rissanen, Marjo Patama, Alessandro Zanetti, and Mari Pihlatie
Atmos. Meas. Tech., 14, 4445–4460, https://doi.org/10.5194/amt-14-4445-2021, https://doi.org/10.5194/amt-14-4445-2021, 2021
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We present ShoTGa-FluMS, a measurement system designed for continuous and automated measurements of trace gas and volatile organic compound (VOC) fluxes from plant shoots. ShoTGa-FluMS uses transparent shoot enclosures equipped with cooling elements, automatically replaces fixated CO2, and removes transpired water from the enclosure, thus solving multiple technical problems that have so far prevented automated plant shoot trace gas flux measurements.
Pharahilda M. Steur, Hubertus A. Scheeren, Dave D. Nelson, J. Barry McManus, and Harro A. J. Meijer
Atmos. Meas. Tech., 14, 4279–4304, https://doi.org/10.5194/amt-14-4279-2021, https://doi.org/10.5194/amt-14-4279-2021, 2021
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For understanding the sources and sinks of atmospheric CO2, measurement of stable isotopes has proven to be highly valuable. We present a new method using laser absorption spectroscopy to simultaneously conduct measurements of three CO2 isotopes, directly on dry-air samples. This new method reduces sample preparation time significantly, compared to the conventional method in which measurements are conducted on pure CO2, and avoids measurement biases introduced by CO2 extraction.
Mingyi Wang, Xu-Cheng He, Henning Finkenzeller, Siddharth Iyer, Dexian Chen, Jiali Shen, Mario Simon, Victoria Hofbauer, Jasper Kirkby, Joachim Curtius, Norbert Maier, Theo Kurtén, Douglas R. Worsnop, Markku Kulmala, Matti Rissanen, Rainer Volkamer, Yee Jun Tham, Neil M. Donahue, and Mikko Sipilä
Atmos. Meas. Tech., 14, 4187–4202, https://doi.org/10.5194/amt-14-4187-2021, https://doi.org/10.5194/amt-14-4187-2021, 2021
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Atmospheric iodine species are often short-lived with low abundance and have thus been challenging to measure. We show that the bromide chemical ionization mass spectrometry, compatible with both the atmospheric pressure and reduced pressure interfaces, can simultaneously detect various gas-phase iodine species. Combining calibration experiments and quantum chemical calculations, we quantify detection sensitivities to HOI, HIO3, I2, and H2SO4, giving detection limits down to < 106 molec. cm-3.
Benjamin Birner, William Paplawsky, Jeffrey Severinghaus, and Ralph F. Keeling
Atmos. Meas. Tech., 14, 2515–2527, https://doi.org/10.5194/amt-14-2515-2021, https://doi.org/10.5194/amt-14-2515-2021, 2021
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The atmospheric helium-to-nitrogen ratio is a promising indicator for circulation changes in the upper atmosphere and fossil fuel burning by humans. We present a very precise analysis method to determine changes in the helium-to-nitrogen ratio of air samples. The method relies on stabilizing the gas flow to a mass spectrometer and continuous removal of reactive gases. These advances enable new insights and monitoring possibilities for anthropogenic and natural processes.
Alexander Zaytsev, Martin Breitenlechner, Anna Novelli, Hendrik Fuchs, Daniel A. Knopf, Jesse H. Kroll, and Frank N. Keutsch
Atmos. Meas. Tech., 14, 2501–2513, https://doi.org/10.5194/amt-14-2501-2021, https://doi.org/10.5194/amt-14-2501-2021, 2021
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We have developed an online method for speciated measurements of organic peroxy radicals and stabilized Criegee intermediates using chemical derivatization combined with chemical ionization mass spectrometry. Chemical derivatization prevents secondary radical reactions and eliminates potential interferences. Comparison between our measurements and results from numeric modeling shows that the method can be used for the quantification of a wide range of atmospheric radicals and intermediates.
Einar Karu, Mengze Li, Lisa Ernle, Carl A. M. Brenninkmeijer, Jos Lelieveld, and Jonathan Williams
Atmos. Meas. Tech., 14, 1817–1831, https://doi.org/10.5194/amt-14-1817-2021, https://doi.org/10.5194/amt-14-1817-2021, 2021
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A gas measurement device was developed to measure trace gases (ppt level) in the air based on an atomic emission detector. It combines a cryogenic pre-concentrator (CryoTrap), a gas chromatograph (GC), and a new high-resolution atomic emission detector (AED). The CryoTrap–GC–AED instrumental setup, limits of detection, and elemental performance are presented and discussed. Two measurement case studies are reported: one in a Finnish boreal forest and the other based on an aircraft campaign.
Ikumi Oyabu, Kenji Kawamura, Kyotaro Kitamura, Remi Dallmayr, Akihiro Kitamura, Chikako Sawada, Jeffrey P. Severinghaus, Ross Beaudette, Anaïs Orsi, Satoshi Sugawara, Shigeyuki Ishidoya, Dorthe Dahl-Jensen, Kumiko Goto-Azuma, Shuji Aoki, and Takakiyo Nakazawa
Atmos. Meas. Tech., 13, 6703–6731, https://doi.org/10.5194/amt-13-6703-2020, https://doi.org/10.5194/amt-13-6703-2020, 2020
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Air in polar ice cores provides information on past atmosphere and climate. We present a new method for simultaneously measuring eight gases (CH4, N2O and CO2 concentrations; isotopic ratios of N2 and O2; elemental ratios between N2, O2 and Ar; and total air content) from single ice-core samples with high precision.
Bernhard Bereiter, Béla Tuzson, Philipp Scheidegger, André Kupferschmid, Herbert Looser, Lars Mächler, Daniel Baggenstos, Jochen Schmitt, Hubertus Fischer, and Lukas Emmenegger
Atmos. Meas. Tech., 13, 6391–6406, https://doi.org/10.5194/amt-13-6391-2020, https://doi.org/10.5194/amt-13-6391-2020, 2020
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The record of past greenhouse gas composition from ice cores is crucial for our understanding of global climate change. Deciphering this archive requires highly accurate and spatially resolved analysis of the very small amount of gas that is trapped in the ice. This is achieved with a mid-IR laser absorption spectrometer that provides simultaneous, high-precision measurements of CH4, N2O, CO2, and δ13C(CO2) and which will be coupled to a quantitative sublimation extraction method.
Natalie I. Keehan, Bellamy Brownwood, Andrey Marsavin, Douglas A. Day, and Juliane L. Fry
Atmos. Meas. Tech., 13, 6255–6269, https://doi.org/10.5194/amt-13-6255-2020, https://doi.org/10.5194/amt-13-6255-2020, 2020
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This paper describes a new instrument (a thermal-dissociation–cavity ring-down spectrometer, TD-CRDS) for the measurement of key atmospheric gaseous and particle-phase molecules containing the nitrate functional group. Several operational considerations affecting the measurements are described, as well as several characterization experiments comparing the TD-CRDS measurements to analogous measurements from other instruments. Examples are given using a TD-CRDS for ambient and laboratory studies.
Mohammed S. Alam, Leigh R. Crilley, James D. Lee, Louisa J. Kramer, Christian Pfrang, Mónica Vázquez-Moreno, Milagros Ródenas, Amalia Muñoz, and William J. Bloss
Atmos. Meas. Tech., 13, 5977–5991, https://doi.org/10.5194/amt-13-5977-2020, https://doi.org/10.5194/amt-13-5977-2020, 2020
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We report on the interference arising in measurements of nitrogen oxides (NOx) from the presence of a range of alkenes in sampled air when using the most widespread air quality monitoring technique for chemiluminescence detection. Interferences of up to 11 % are reported, depending upon the alkene present and conditions used. Such interferences may be of substantial importance for the interpretation of ambient NOx data, particularly for high volatile organic compound and low NOx environments.
Daniel Marno, Cheryl Ernest, Korbinian Hens, Umar Javed, Thomas Klimach, Monica Martinez, Markus Rudolf, Jos Lelieveld, and Hartwig Harder
Atmos. Meas. Tech., 13, 2711–2731, https://doi.org/10.5194/amt-13-2711-2020, https://doi.org/10.5194/amt-13-2711-2020, 2020
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In this study, a calibration device for OH and HO2 instruments is characterized at pressures of 275 to 1000 mbar, allowing instrument pressure sensitivity to be quantified to an accuracy of 22 % (1σ). Computational fluid dynamic simulations supporting the understanding of interactions between generated HOx and the instrument inlet led to enhanced determination of factors affecting instrument sensitivity.
Joschka Pfeifer, Mario Simon, Martin Heinritzi, Felix Piel, Lena Weitz, Dongyu Wang, Manuel Granzin, Tatjana Müller, Steffen Bräkling, Jasper Kirkby, Joachim Curtius, and Andreas Kürten
Atmos. Meas. Tech., 13, 2501–2522, https://doi.org/10.5194/amt-13-2501-2020, https://doi.org/10.5194/amt-13-2501-2020, 2020
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Ammonia is an important atmospheric trace gas that affects secondary aerosol formation and, together with sulfuric acid, the formation of new particles. A measurement technique is presented that uses high-resolution mass spectrometry and protonated water clusters for the ultrasensitive detection of ammonia at single-digit parts per trillion by volume levels. The instrument is further capable of measuring amines and a suite of iodine compounds at sub-parts per trillion by volume levels.
Roberto Sommariva, Louisa J. Kramer, Leigh R. Crilley, Mohammed S. Alam, and William J. Bloss
Atmos. Meas. Tech., 13, 1655–1670, https://doi.org/10.5194/amt-13-1655-2020, https://doi.org/10.5194/amt-13-1655-2020, 2020
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Ozone is a key atmospheric pollutant formed through chemical processing of natural and anthropogenic emissions and removed by reaction with organic compounds emitted by plants. We describe a new instrument – the
Total Ozone Reactivity Systemor TORS – that measures the total loss of ozone in the troposphere. The objective of the TORS instrument is to provide an estimate of the organic compounds emitted by plants which are not measured and thus to improve our understanding of the ozone budget.
John W. Birks, Andrew A. Turnipseed, Peter C. Andersen, Craig J. Williford, Stanley Strunk, Brian Carpenter, and Christine A. Ennis
Atmos. Meas. Tech., 13, 1001–1018, https://doi.org/10.5194/amt-13-1001-2020, https://doi.org/10.5194/amt-13-1001-2020, 2020
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We describe a portable calibration source of nitric oxide (NO) based on the photolysis of nitrous oxide. Combining this with a previous photolytic ozone (O3) source yields a calibrator that produces known mixing ratios of NO, O3, and nitrogen dioxide (NO2); NO2 is produced by the reaction of NO with O3. This portable
NO2/NO/O3 calibration source requires no external gas cylinders and can be used as a standard to calibrate O3 and NOx air pollution monitors in the field.
Ece Satar, Peter Nyfeler, Bernhard Bereiter, Céline Pascale, Bernhard Niederhauser, and Markus Leuenberger
Atmos. Meas. Tech., 13, 101–117, https://doi.org/10.5194/amt-13-101-2020, https://doi.org/10.5194/amt-13-101-2020, 2020
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Good-quality measurements of atmospheric trace gases are only possible with regular calibrations and stable measurements from the standard cylinders. This study investigates instabilities due to surface effects on newly built aluminum and steel cylinders. We present measurements over a set of temperature and pressure ranges for the amount fractions of CO2, CO, CH4 and H2O using a commercial and a novel laser spectroscopic analyzer.
Ece Satar, Peter Nyfeler, Céline Pascale, Bernhard Niederhauser, and Markus Leuenberger
Atmos. Meas. Tech., 13, 119–130, https://doi.org/10.5194/amt-13-119-2020, https://doi.org/10.5194/amt-13-119-2020, 2020
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To ensure the best preparation and measurement conditions for trace gases, usage of coated materials is in demand in gas metrology and atmospheric measurement communities. In this article, the previously introduced aluminum measurement chamber is used to investigate materials such as glass, aluminum, copper, brass, steel and three different commercially available coatings. Our measurements focus on temperature and pressure dependencies for the species CO2, CO, CH4 and H2O using a CRDS analyzer.
Tanja J. Schuck, Ann-Katrin Blank, Elisa Rittmeier, Jonathan Williams, Carl A. M. Brenninkmeijer, Andreas Engel, and Andreas Zahn
Atmos. Meas. Tech., 13, 73–84, https://doi.org/10.5194/amt-13-73-2020, https://doi.org/10.5194/amt-13-73-2020, 2020
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Air sample collection aboard aircraft is a tool to measure atmospheric trace gas mixing ratios at altitude. We present results on the stability of 28 halocarbons during storage of air samples collected in stainless-steel flasks inside an automated air sampling unit which is part of the CARIBIC instrument package. Selected fluorinated compounds grew during the experiments while short-lived compounds were depleted. Individual substances were additionally influenced by high mixing ratios of ozone.
Tesfaye A. Berhanu, John Hoffnagle, Chris Rella, David Kimhak, Peter Nyfeler, and Markus Leuenberger
Atmos. Meas. Tech., 12, 6803–6826, https://doi.org/10.5194/amt-12-6803-2019, https://doi.org/10.5194/amt-12-6803-2019, 2019
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Accurate measurement of variations in atmospheric O2 can provide useful information about atmospheric, biospheric, and oceanic processes, which is a challenge for existing measurement techniques. Here, we introduce a newly built high-precision, stable CRDS analyzer (Picarro G2207) that can measure O2 mixing ratios with a short-term precision of < 1 ppm and only requires calibration every 12 h. Measurements from tower and mountain sites are also presented.
Markus Leiminger, Stefan Feil, Paul Mutschlechner, Arttu Ylisirniö, Daniel Gunsch, Lukas Fischer, Alfons Jordan, Siegfried Schobesberger, Armin Hansel, and Gerhard Steiner
Atmos. Meas. Tech., 12, 5231–5246, https://doi.org/10.5194/amt-12-5231-2019, https://doi.org/10.5194/amt-12-5231-2019, 2019
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We introduce an alternative type of atmospheric pressure interface time-of-flight mass spectrometer (APi-TOF) with the main difference of using hexapole instead of quadrupole ion guides. The transfer of cluster ions through the hexapoles was characterised with focus on transmission efficiency, mass range and fragmentation of cluster ions. At the CERN CLOUD experiment we compared the performance of the ioniAPi-TOF with a standard quadrupole APi-TOF under controlled conditions.
Michal Lacko, Nijing Wang, Kristýna Sovová, Pavel Pásztor, and Patrik Španěl
Atmos. Meas. Tech., 12, 4965–4982, https://doi.org/10.5194/amt-12-4965-2019, https://doi.org/10.5194/amt-12-4965-2019, 2019
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The soft chemical ionization analytical technique of selected ion flow tube mass spectrometry, SIFT-MS, was enhanced by a fast GC pre-separation unit to identify individual isomers. Experiments were carried out with two GC columns, MXT-1 and MXT-Volatiles, using two reagent ions, H3O+ and NO+, on monoterpene samples (an artificial mixture and coniferous needles). Analyses of product ion ratios allowed for quantification of multiple monoterpenes in partially separated chromatograms.
Benjamin L. Deming, Demetrios Pagonis, Xiaoxi Liu, Douglas A. Day, Ranajit Talukdar, Jordan E. Krechmer, Joost A. de Gouw, Jose L. Jimenez, and Paul J. Ziemann
Atmos. Meas. Tech., 12, 3453–3461, https://doi.org/10.5194/amt-12-3453-2019, https://doi.org/10.5194/amt-12-3453-2019, 2019
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Losses or measurement delays of gas-phase compounds sampled through tubing are important to atmospheric science. Here we characterize 14 tubing materials by measuring the effects on step changes in organic compound concentration. We find that polymeric tubings exhibit absorptive partitioning behaviour while glass and metal tubings show adsorptive partitioning. Adsorptive materials impart complex humidity, concentration, and VOC–VOC interaction dependencies that absorptive tubings do not.
Xiaoxi Liu, Benjamin Deming, Demetrios Pagonis, Douglas A. Day, Brett B. Palm, Ranajit Talukdar, James M. Roberts, Patrick R. Veres, Jordan E. Krechmer, Joel A. Thornton, Joost A. de Gouw, Paul J. Ziemann, and Jose L. Jimenez
Atmos. Meas. Tech., 12, 3137–3149, https://doi.org/10.5194/amt-12-3137-2019, https://doi.org/10.5194/amt-12-3137-2019, 2019
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Delays or losses of gases in sampling tubing and instrumental surfaces due to surface interactions can lead to inaccurate quantification. By sampling with several chemical ionization mass spectrometers and six tubing materials, we quantify delays of semivolatile organic compounds and small polar gases. Delay times generally increase with decreasing volatility or increasing polarity and also depend on materials. The method and results will inform inlet material selection and instrumental design.
Emmanuel Arzoumanian, Felix R. Vogel, Ana Bastos, Bakhram Gaynullin, Olivier Laurent, Michel Ramonet, and Philippe Ciais
Atmos. Meas. Tech., 12, 2665–2677, https://doi.org/10.5194/amt-12-2665-2019, https://doi.org/10.5194/amt-12-2665-2019, 2019
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We tested commercial lower-cost CO2 sensors in laboratory and field studies to see if they can measure atmospheric CO2 mole fractions with less than 1 ppm bias (with monthly calibration), to allow continuous urban CO2 monitoring.
We find that the sensors' CO2 readings are influenced by temperature, atmospheric pressure and water vapour content, but this can be corrected for by adding sensors (T, p, RH) and carefully calibrating each sensor against a high-precision instrument.
Matthieu Riva, Pekka Rantala, Jordan E. Krechmer, Otso Peräkylä, Yanjun Zhang, Liine Heikkinen, Olga Garmash, Chao Yan, Markku Kulmala, Douglas Worsnop, and Mikael Ehn
Atmos. Meas. Tech., 12, 2403–2421, https://doi.org/10.5194/amt-12-2403-2019, https://doi.org/10.5194/amt-12-2403-2019, 2019
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The impact of aerosol particles on climate and air quality remains poorly understood due to multiple factors. One of the current limitations is the incomplete understanding of the contribution of oxygenated species, formed from the oxidation of volatile organic compounds (VOCs) to aerosol formation. Taking advantage of recent mass spectrometric developments, we have evaluated and compared the capability of multiple state-of-the-art mass spectrometers to detect a wide variety of oxygenated VOCs.
Yufeng Pan, Lei Dong, Hongpeng Wu, Weiguang Ma, Lei Zhang, Wangbao Yin, Liantuan Xiao, Suotang Jia, and Frank K. Tittel
Atmos. Meas. Tech., 12, 1905–1911, https://doi.org/10.5194/amt-12-1905-2019, https://doi.org/10.5194/amt-12-1905-2019, 2019
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Photoacoustic spectroscopy has one important advantage: its sensitivity is proportional to the excitation light power and thus the performance of PAS-based sensors can benefit from a high excitation light power. We developed a cavity-enhanced photoacoustic sensor in which a photoacoustic cell was placed into a high-finesse optical cavity. A signal gain factor of 166 was observed. For C2H2 detection, a 1σ detection limit of 0.45 ppmV was obtained at atmospheric pressure with a 1 s averaging time.
Alexander Zaytsev, Martin Breitenlechner, Abigail R. Koss, Christopher Y. Lim, James C. Rowe, Jesse H. Kroll, and Frank N. Keutsch
Atmos. Meas. Tech., 12, 1861–1870, https://doi.org/10.5194/amt-12-1861-2019, https://doi.org/10.5194/amt-12-1861-2019, 2019
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We present the development of a chemical ionization mass spectrometer which can be operated with either ammonium (NH4+) or hydronium (H3O+) as the reagent ion. We describe a mass spectrometric voltage scanning procedure based on collision-induced dissociation that allows us to determine the stability of detected ammonium–organic ions and hence constrain the sensitivity of the instrument to a wide range of organic compounds that cannot be calibrated directly.
Nick Jordan, Connie Z. Ye, Satyaki Ghosh, Rebecca A. Washenfelder, Steven S. Brown, and Hans D. Osthoff
Atmos. Meas. Tech., 12, 1277–1293, https://doi.org/10.5194/amt-12-1277-2019, https://doi.org/10.5194/amt-12-1277-2019, 2019
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A new spectrometer to measure abundances of the atmospheric trace gases nitrogen dioxide and iodine is described. The spectrometer uses a light-emitting diode between 470 and 540 nm and two highly reflective mirrors to yield an effective absorption path of 6.3 km. We remeasured scattering cross sections of common atmospheric gases in the cyan region and present sample NO2 measurements that agreed with those made with a laser-based instrument.
Kazuki Kamezaki, Shohei Hattori, Enno Bahlmann, and Naohiro Yoshida
Atmos. Meas. Tech., 12, 1141–1154, https://doi.org/10.5194/amt-12-1141-2019, https://doi.org/10.5194/amt-12-1141-2019, 2019
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Knowledge related to sulfur isotopic composition of carbonyl sulfide (OCS or COS), the most abundant atmospheric sulfur species, remains scarce. We present a new sampling system for collecting approx. 10 nmol of OCS from ambient air coupled with a purification system. The system presented herein is useful for application of sulfur isotopic compositions for investigation of OCS sources and sinks in the troposphere to elucidate its cycle and its contribution to background stratospheric sulfate.
Jeremy J. Harrison
Atmos. Meas. Tech., 11, 5827–5836, https://doi.org/10.5194/amt-11-5827-2018, https://doi.org/10.5194/amt-11-5827-2018, 2018
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CFC-11 is a stratospheric-ozone-depleting molecule which is banned under the Montreal Protocol but still present in the atmosphere due to its long lifetime. Using infrared limb sounders on satellite platforms to monitor its concentration crucially requires accurate laboratory spectroscopic data. This paper describes a new high-resolution infrared absorption cross-section dataset for remote-sensing purposes; this improves upon the one currently available in the HITRAN and GEISA databases.
Michael F. Schibig, Duane Kitzis, and Pieter P. Tans
Atmos. Meas. Tech., 11, 5565–5586, https://doi.org/10.5194/amt-11-5565-2018, https://doi.org/10.5194/amt-11-5565-2018, 2018
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For long-term monitoring of CO2 in the atmosphere it is crucial that standard reference gas mixtures stored in high-pressure aluminum cylinders, used to calibrate global measurements, remain stable over their whole time of use. This study finds a reproducible small enrichment as a cylinder is emptied at a low-flow rate, as well as somewhat larger and variable effects when a cylinder is emptied using a high-flow rate.
Min Jie Zhao, Fu Qi Si, Hai Jin Zhou, Shi Mei Wang, Yu Jiang, and Wen Qing Liu
Atmos. Meas. Tech., 11, 5403–5419, https://doi.org/10.5194/amt-11-5403-2018, https://doi.org/10.5194/amt-11-5403-2018, 2018
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EMI is a nadir-viewing wide-field imaging spectrometer aiming to quantify the global distribution of tropospheric and stratospheric trace gases. The spectral range is 240–710 nm, with the spectral resolution 0.3–0.5 nm. The preflight accuracy of wavelength calibration is less than 0.05 nm; the accuracy of radiance calibration is less than 5 %. The obtained calibration key data are used for the L1b processor. In-orbit wavelength/radiometric calibration is used to monitor performance changes.
Anne-Kathrin Bernhammer, Lukas Fischer, Bernhard Mentler, Martin Heinritzi, Mario Simon, and Armin Hansel
Atmos. Meas. Tech., 11, 4763–4773, https://doi.org/10.5194/amt-11-4763-2018, https://doi.org/10.5194/amt-11-4763-2018, 2018
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During new particle formation (NPF) studies from pure isoprene oxidation in the CLOUD chamber at CERN we observed unexpected ion signals. We identified two origins of these signals: first secondary association reactions of protonated isoprene with isoprene within the PTR3 reaction chamber and, second, polymerization of isoprene inside the gas bottle.
In order to study NPF from pure isoprene oxidation we had to install a cryogenic trap in the isoprene inlet line to remove polymerized isoprene.
Cited articles
Agbro, E., Tomlin, A. S., Lawes, M., Park, S., and Sarathy, S. M.: The
influence of n-butanol blending on the ignition delay times of gasoline and
its surrogates at high pressures, Fuel, 187, 211–219, https://doi.org/10.1016/j.fuel.201609.052, 2017.
Assaf, E. and Fittschen, C.: Cross Section of OH Radical Overtone Transition near 7028 cm−1 and Measurement of the Rate Constant of the
Reaction of OH with HO2 Radicals, J. Phys. Chem. A, 120, 7051–7059, https://doi.org/10.1021/acs.jpca.6b06477, 2016.
Assaf, E., Liu, L., Schoemaecker, C., and Fittschen, C.: Absorption spectrum
and absorption cross sections of the 2v1 band of HO2 between 20
and 760 Torr air in the range 6636 and 6639 cm−1, J. Quant. Spectrosc. Ra., 211, 107–114, https://doi.org/10.1016/j.jqsrt.2018.02.035, 2018.
Atkinson, R., Aschmann, S. M., Winer, A. M., and Pitts, J. N.: Rate constants for the reaction of OH radicals with a series of alkanes and alkenes at 299 ±2 K, Int. J. Chem. Kinet., 14, 507–516, https://doi.org/10.1002/kin.550140508, 1982.
Atkinson, R., Baulch, D. L., Cox, R. A., Crowley, J. N., Hampson, R. F., Hynes, R. G., Jenkin, M. E., Rossi, M. J., Troe, J., and IUPAC Subcommittee: Evaluated kinetic and photochemical data for atmospheric chemistry: Volume II – gas phase reactions of organic species, Atmos. Chem. Phys., 6, 3625–4055, https://doi.org/10.5194/acp-6-3625-2006, 2006.
Baeza-Romero, M. T., Blitz, M. A., Goddard, A., and Seakins, P. W.:
Time-of-flight mass spectrometry for time-resolved measurements: Some
developments and applications, Int. J. Chem. Kinet., 44, 532–545, https://doi.org/10.1002/kin.20620, 2012.
Brune, W. H., Stevens, P. S., and Mather, J. H.: Measuring OH and HO2
in the troposphere by laser-induced fluorescence at low-pressure, J. Atmos.
Sci., 52, 3328–3336, https://doi.org/10.1175/1520-0469(1995)052<3328:MOAHIT>2.0.CO;2, 1995.
Cavalli, F., Geiger, H., Barnes, I., and Becker, K. H.: FTIR kinetic, product, and modeling study of the OH-initiated oxidation of 1-butanol in air, Environ. Sci. Technol., 36, 1263–1270, https://doi.org/10.1021/es010220s, 2002.
Crowley, J. N., Simon, F. G., Burrows, J. P., Moortgat, G. K., Jenkin, M. E., and Cox, R. A.: The HO2 radical UV absorption-spectrum measured by molecular modulation, UV diode-array spectroscopy, J. Photoch. Photobio. A, 60, 1–10, https://doi.org/10.1016/1010-6030(91)90001-a, 1991.
Dunlop, J. R. and Tully, F. P.: A kinetic study of OH radical reactions
with methane and perdeuterated methane, J. Phys. Chem., 97, 11148–11150, https://doi.org/10.1021/j100145a003, 1993.
Edwards, G. D., Cantrell, C. A., Stephens, S., Hill, B., Goyea, O., Shetter,
R. E., Mauldin, R. L., Kosciuch, E., Tanner, D. J., and Eisele, F. L.:
Chemical ionization mass spectrometer instrument for the measurement of
tropospheric HO2 and RO2, Anal. Chem., 75, 5317–5327, https://doi.org/10.1021/ac034402b, 2003.
Fuchs, H., Bohn, B., Hofzumahaus, A., Holland, F., Lu, K. D., Nehr, S., Rohrer, F., and Wahner, A.: Detection of HO2 by laser-induced fluorescence: calibration and interferences from RO2 radicals, Atmos. Meas. Tech., 4, 1209–1225, https://doi.org/10.5194/amt-4-1209-2011, 2011.
Gianella, M., Reuter, S., Aguila, A. L., Ritchie, G. A. D., and van Helden,
J. P. H.: Detection of HO2 in an atmospheric pressure plasma jet using
optical feedback cavity-enhanced absorption spectroscopy, New J. Phys., 18, 113027, https://doi.org/10.1088/1367-2630/18/11/113027, 2016.
Glowacki, D. R., Goddard, A., Hemavibool, K., Malkin, T. L., Commane, R., Anderson, F., Bloss, W. J., Heard, D. E., Ingham, T., Pilling, M. J., and Seakins, P. W.: Design of and initial results from a Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC), Atmos. Chem. Phys., 7, 5371–5390, https://doi.org/10.5194/acp-7-5371-2007,
2007.
Hanke, M., Uecker, J., Reiner, T., and Arnold, F.: Atmospheric peroxy radicals: ROXMAS, a new mass-spectrometric methodology for speciated measurements of HO2 and SRO2 and first results, Int. J. Mass Spectrom., 213, 91–99, https://doi.org/10.1016/s1387-3806(01)00548-6, 2002.
Hard, T. M., O'Brien, R. J., Chan, C. Y., and Mehrabzadeh, A. A.: Tropospheric Free-radical determination by FAGE, Environ. Sci. Technol., 18, 768–777, 1984.
Hurley, M. D., Wallington, T. J., Lauirsen, L., Javadi, M. S., Nielsen, O.
J., Yamanaka, T., and Kawasaki, M.: Atmospheric Chemistry of n-Butanol:
Kinetics, Mechanisms, and Products of Cl Atom and OH Radical Initiated
Oxidation in the Presence and Absence of NOx, J. Phys. Chem. A, 113,
7011–7020, https://doi.org/10.1021/jp810585c, 2009.
Jemialade, A. A. and Thrush, B. A.: Reactions of HO2 with NO and
NO2 studied by midinfrared laser magnetic-resonance, J. Chem. Soc. Faraday T., 86, 3355–3363, https://doi.org/10.1039/ft9908603355,
1990.
McCaulley, J. A., Kelly, N., Golde, M. F., and Kaufman, F.: Kinetic studies
of the reactions of F and OH with CH3OH, J. Phys. Chem., 93, 1014–1018, https://doi.org/10.1021/j100340a002, 1989.
McGillen, M. R., Baasandorj, M., and Burkholder, J. B.: Gas-Phase Rate
Coefficients for the OH plus n-, i-, s-, and t-Butanol Reactions Measured
Between 220 and 380 K: Non-Arrhenius Behavior and Site-Specific Reactivity,
J. Phys. Chem. A, 117, 4636–4656, https://doi.org/10.1021/jp402702u, 2013.
Medeiros, D. J., Blitz, M. A., James, L., Speak, T. H., and Seakins, P. W.:
Kinetics of the Reaction of OH with Isoprene over a Wide Range of
Temperature and Pressure Including Direct Observation of Equilibrium with
the OH Adducts, J. Phys. Chem. A, 122, 7239–7255, https://doi.org/10.1021/acs.jpca.8b04829,
2018.
Monks, P. S.: Gas-phase radical chemistry in the troposphere, Chem. Soc. Rev., 34, 376–395, https://doi.org/10.1039/B307982C, 2005.
Moore, S. B. and Carr, R. W.: Molecular velocity distribution effects in
kinetic studies by time-resolved mass-spectrometry, Int. J. Mass Spectrom., 24, 161–171, https://doi.org/10.1016/0020-7381(77)80023-5, 1977.
Nehr, S., Bohn, B., Fuchs, H., Hofzumahaus, A., and Wahner, A.: HO2
formation from the OH plus benzene reaction in the presence of O2,
Phys. Chem. Chem. Phys., 13, 10699–10708, https://doi.org/10.1039/c1cp20334g, 2011.
Onel, L., Brennan, A., Gianella, M., Ronnie, G., Lawry Aguila, A., Hancock, G., Whalley, L., Seakins, P. W., Ritchie, G. A. D., and Heard, D. E.: An intercomparison of HO2 measurements by fluorescence assay by gas expansion and cavity ring-down spectroscopy within HIRAC (Highly Instrumented Reactor for Atmospheric Chemistry), Atmos. Meas. Tech., 10, 4877–4894, https://doi.org/10.5194/amt-10-4877-2017, 2017.
Orlando, J. J., Tyndall, G. S., Bilde, M., Ferronato, C., Wallington, T. J.,
Vereecken, L., and Peeters, J.: Laboratory and theoretical study of the oxy
radicals in the OH- and Cl-initiated oxidation of ethene, J. Phys. Chem. A,
102, 8116–8123, https://doi.org/10.1021/jp981937d, 1998.
Orlando, J. J., Tyndall, G. S., and Wallington, T. J.: The atmospheric
chemistry of alkoxy radicals, Chem. Rev., 103, 4657–4689, 2003.
Reitz, R. D. and Duraisamy, G.: Review of high efficiency and clean reactivity controlled compression ignition (RCCI) combustion in internal
combustion engines, Prog. Energ. Combust., 46, 12–71, https://doi.org/10.1016/j.pecs.2014.05.003, 2015.
Speak, T. H., Blitz, M. A., Stone, D., and Seakins, P. W.: Data for the publication “A new instrument for time-resolved measurement of HO2 radicals”, University of Leeds, Leeds, UK, https://doi.org/10.5518/743, 2019.
Stockwell, W. R., Lawson, C. V., Saunders, E., and Goliff, W. S.: A Review
of Tropospheric Atmospheric Chemistry and Gas-Phase Chemical Mechanisms for
Air Quality Modeling, Atmosphere, 3, 1–32, 2012.
Stone, D., Whalley, L. K., and Heard, D. E.: Tropospheric OH and HO2
radicals: field measurements and model comparisons, Chem. Soc. Rev., 41,
6348–6404, https://doi.org/10.1039/c2cs35140d, 2012.
Stone, D., Blitz, M., Ingham, T., Onel, L., Medeiros, D. J., and Seakins, P.
W.: An instrument to measure fast gas phase radical kinetics at high
temperatures and pressures, Rev. Sci. Instrum., 87, 054102, https://doi.org/10.1063/1.4950906, 2016.
Taatjes, C. A. and Oh, D. B.: Time-resolved wavelength modulation spectroscopy measurements of HO2 kinetics, Appl. Optics, 36, 5817–5821, https://doi.org/10.1364/ao.36.005817, 1997.
Taatjes, C. A.: How does the molecular velocity distribution affect kinetics
measurements by time-resolved mass spectrometry?, Int. J. Chem. Kinet., 39,
565–570, https://doi.org/10.1002/kin.20262, 2007.
Thiebaud, J. and Fittschen, C.: Near infrared cw-CRDS coupled to laser
photolysis: Spectroscopy and kinetics of the HO2 radical, Appl. Phys.
B-Lasers O., 85, 383–389, https://doi.org/10.1007/s00340-006-2304-0, 2006.
Tully, F. P.: Laser photolysis laser-induced fluorescence study of the
reaction of hydroxyl radical with ethylene, Chem. Phys. Lett., 96, 148–153, https://doi.org/10.1016/0009-2614(83)80481-3, 1983.
Whalley, L. K., Blitz, M. A., Desservettaz, M., Seakins, P. W., and Heard, D. E.: Reporting the sensitivity of laser-induced fluorescence instruments used for HO2 detection to an interference from RO2 radicals and introducing a novel approach that enables HO2 and certain RO2 types to be selectively measured, Atmos. Meas. Tech., 6, 3425–3440, https://doi.org/10.5194/amt-6-3425-2013, 2013.
Wine, P. H., Semmes, D. H., and Ravishankara, A. R.: A laser
flash-photolysis kinetics study of the reaction
Winiberg, F. A. F., Smith, S. C., Bejan, I., Brumby, C. A., Ingham, T., Malkin, T. L., Orr, S. C., Heard, D. E., and Seakins, P. W.: Pressure-dependent calibration of the OH and HO2 channels of a FAGE HOx instrument using the Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC), Atmos. Meas. Tech., 8, 523–540, https://doi.org/10.5194/amt-8-523-2015, 2015.
Zador, J., Taatjes, C. A., and Fernandes, R. X.: Kinetics of elementary reactions in low-temperature autoignition chemistry, Prog. Energ. Combust., 37, 371–421, https://doi.org/10.1016/j.pecs.2010.06.006, 2011.
Short summary
OH and HO2 radicals are important trace constituents of the atmosphere that are closely coupled via several types of reaction. This paper describes a new laboratory method to simultaneously determine OH kinetics and HO2 yields from chemical processes. The instrument also provides some time resolution on HO2 detection allowing one to separate HO2 produced from the target reaction from HO2 arising from secondary chemistry. Examples of applications are presented.
OH and HO2 radicals are important trace constituents of the atmosphere that are closely coupled...
