Daytime Atmospheric Halogen Cycling through Aqueous-Phase Oxygen Atom Chemistry

Dalton, Evan Z.; Hoffmann, Erik; Schaefer, Thomas; Tilgner, Andreas; Herrmann, Hartmut; Raff, Jonathan D.

doi:10.1021/jacs.3c03112

Cited by 6 publications

(4 citation statements)

References 53 publications

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“…Based on the present measurements, it is not clear whether this occurs in surface waters (such as holding ponds or storage tanks) or in aerosols (such as droplets or aerosols generated during fluid usage and pumping). This mechanism would be consistent with studies , that have shown that photoactive processes can drive inorganic halogen formation in chloride-containing aerosols of different compositions. However, due to the variable and proprietary water compositions, we are unable to point to a specific photoactive agent that may initiate Cl 2 formation.…”

Section: Resultssupporting

confidence: 92%

High Chlorine Concentrations in an Unconventional Oil and Gas Development Region and Impacts on Atmospheric Chemistry

Masoud,

Modi,

Bhattacharyya

et al. 2023

Environ. Sci. Technol.

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Growth in unconventional oil and gas development (UOGD) in the United States has increased airborne emissions, raising environmental and human health concerns. To assess the potential impacts on air quality, we deployed instrumentation in Karnes City, Texas, a rural area in the middle of the Eagle Ford Shale. We measured several episodes of elevated Cl 2 levels, reaching maximum hourly averages of 800 ppt, the highest inland Cl 2 concentration reported to date. Concentrations peak during the day, suggesting a strong local source (given the short photolysis lifetime of Cl 2 ) and/or a photoinitiated production mechanism. Well preproduction activity near the measurement site is a plausible source of these high Cl 2 levels via direct emission and photoactive chemistry. ClNO 2 is also observed, but it peaks overnight, consistent with well-known nocturnal formation processes. Observations of organochlorines in the gas and particle phases reflect the contribution of chlorine chemistry to the formation of secondary pollutants in the area. Box modeling results suggest that the formation of ozone at this location is influenced by chlorine chemistry. These results suggest that UOGD can be an important source of reactive chlorine in the atmosphere, impacting radical budgets and the formation of secondary pollutants in these regions.

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Section: Resultssupporting

confidence: 92%

High Chlorine Concentrations in an Unconventional Oil and Gas Development Region and Impacts on Atmospheric Chemistry

Masoud,

Modi,

Bhattacharyya

et al. 2023

Environ. Sci. Technol.

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“…Enhanced production of HONO by an energy transfer mechanism through organic chromophores can potentially contribute to the missing budget for daytime HONO production. Furthermore, this study expands our understanding of nitrate photochemistry within single aqueous droplets, an active area of research that has recently shown some additional aspects of nitrate photochemistry including the importance of the role of excited states, and aqueous aerosol size, as well as the impact on halogen cycling for this reaction …”

mentioning

confidence: 85%

Photoinduced Reactions of Nitrate in Aqueous Microdroplets by Triplet Energy Transfer

Kim,

Boothby,

Grassian

et al. 2023

J. Phys. Chem. Lett.

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“…For only four stations, the simulated difference in the concentration is slightly higher than a factor of two. insoluble and efficiently transfer chlorine to the gas phase (Soni et al, 2023;Dalton et al, 2023). The aerosol pH is defined as the negative decimal logarithm of the hydrogen ion activity (a H + ):…”

Section: Ammonium (Nh + 4 )mentioning

confidence: 99%

“…However, model studies are usually limited to the representation of relevant chemistry by using surface reactions uptake coefficients with little dependence on aerosol composition. In AERCHEM, key reactions for the production of HONO, ClNO 2 and Cl 2 can now be investigated by incorporating the recent advancements on the multiphase kinetics of chlorine (Soni et al, 2023;Dalton et al, 2023).…”

Section: Crustal Elementsmentioning

confidence: 99%

How non-equilibrium aerosol chemistry impacts particle acidity: the GMXe AERosol CHEMistry (GMXe–AERCHEM, v1.0) sub-submodel of MESSy

Rosanka,

Tost,

Sander

et al. 2023

Preprint

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Abstract. Aqueous-phase chemical processes in clouds, fog, and deliquescent aerosols are known to alter atmospheric composition and acidity significantly. Traditionally, global and regional models predict aerosol composition by relying on thermodynamic equilibrium models and neglect non-equilibrium processes. Here, we present the AERosol CHEMistry (GMXe–AERCHEM, v1.0) sub-submodel developed for the Modular Earth Submodel System (MESSy) as an add-on to the thermodynamic equilibrium model (i.e., ISORROPIA-II) used by MESSy’s Global Modal-aerosol eXtension (GMXe) submodel. AERCHEM allows the representation of non-equilibrium aqueous-phase chemistry of varying complexity in deliquescent fine aerosols. We perform a global simulation for the year 2010 by using the available detailed kinetic model for the chemistry of inorganic and small oxygenated organics. We evaluate AERCHEM’s performance by comparing the simulated concentrations of sulfate, nitrate, ammonium, and chloride to in situ measurements of three monitoring networks. Overall, AERCHEM reproduces observed concentrations reasonably well. We find that especially in the USA, the consideration of non-equilibrium chemistry in deliquescent aerosols reduces the model bias for sulfate, nitrate, and ammonium, when compared to simulated concentrations by ISORROPIA-II. Over most continental regions, fine aerosol acidity simulated by AERCHEM is similar to the predictions by ISORROPIA-II but tends to simulate slightly lower aerosol acidity in most regions. The consideration of non-equilibrium chemistry in deliquescent aerosols leads to a significant higher aerosol acidity in the marine boundary layer, which is in line with observations and recent literature. AERCHEM allows investigating the global-scale impact of aerosol non-equilibrium chemistry on atmospheric composition. This will aid the exploration of key multiphase processes and improve the model predictions for oxidation capacity and aerosols in the troposphere.

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Daytime Atmospheric Halogen Cycling through Aqueous-Phase Oxygen Atom Chemistry

Cited by 6 publications

References 53 publications

High Chlorine Concentrations in an Unconventional Oil and Gas Development Region and Impacts on Atmospheric Chemistry

High Chlorine Concentrations in an Unconventional Oil and Gas Development Region and Impacts on Atmospheric Chemistry

Photoinduced Reactions of Nitrate in Aqueous Microdroplets by Triplet Energy Transfer

How non-equilibrium aerosol chemistry impacts particle acidity: the GMXe AERosol CHEMistry (GMXe–AERCHEM, v1.0) sub-submodel of MESSy

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