Dimethyl sulfide chemistry over the industrial era: comparison of key oxidation mechanisms and long-term observations DOI Creative Commons
Ursula A. Jongebloed, Jacob I. Chalif, Linia Tashmim

et al.

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(7), P. 4083 - 4106

Published: April 10, 2025

Abstract. Dimethyl sulfide (DMS) is primarily emitted by marine phytoplankton and oxidized in the atmosphere to form methanesulfonic acid (MSA) sulfate aerosols. Ice cores regions affected anthropogenic pollution show an industrial-era decline MSA, which has previously been interpreted as indicating a abundance. However, simultaneous increase DMS-derived (bioSO4) Greenland ice core suggests that pollution-driven oxidant changes caused MSA influencing relative production of versus bioSO4. Here we use GEOS-Chem, global chemical transport model, zero-dimensional box model over three time periods (preindustrial era, peak North Atlantic NOx pollution, 21st century) investigate drivers bioSO4, examine whether four DMS oxidation mechanisms reproduce trends seasonality observations. We find GEOS-Chem simulations can only partially bioSO4 wide variation results reflects sensitivity mechanism concentrations. Our support hypothesized nitrate radical industrial increases production, but competing factors such BrO result increased some simulations, inconsistent with To improve understanding oxidation, future work should aqueous-phase chemistry, produces 82 %–99 % our constrain atmospheric concentrations, including radical, hydroxyl reactive halogens.

Language: Английский

Significant Impact of a Daytime Halogen Oxidant on Coastal Air Quality DOI Creative Commons
Jianing Dai, Tao Wang, Hengqing Shen

et al.

Environmental Science & Technology, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 24, 2025

Chlorine radicals (Cl·) are highly reactive and affect the fate of air pollutants. Several field studies in China have revealed elevated levels daytime molecular chlorine (Cl2), which, upon photolysis, release substantial amounts Cl· but poorly represented current chemical transport models. Here, we implemented a parametrization for formation Cl2 through photodissociation particulate nitrate acidic environments into regional model assessed its impact on coastal quality during autumn South China. The could reproduce over 70% high level measured at site, revealing discernible presence released adjacent areas. Abundant alters oxidative capacity atmosphere, consequently increasing O3 (6–12%) PM2.5 (10–16%) concentrations high-NOx areas reducing (3%) concentration low-NOx Accounting chemistry shifts – precursor relationships from VOC limited to mixed or NOx -limited regimes, enhancing benefits emission reduction mitigating pollution. Our findings suggest that tightening control two pollutants, SO2, would alleviate production adverse quality.

Language: Английский

Citations

1
Comments on ‘Intended and Unintended Consequences of Atmospheric Methane Oxidation Enhancement’ DOI Creative Commons
Matthew S. Johnson

Published: Jan. 5, 2025

Abstract. Atmospheric oxidation enhancement (AOE) of methane via either tropospheric hydroxyl radicals (OH) or chlorine (Cl) is being considered as a method to decrease greenhouse gas concentrations. The chemistry involved coupled; nonlinear; and affects air quality, other gases, ozone-depleting substances. Here I perform suite experiments in three-dimensional (3D) atmospheric model representing different OH- Cl-based methods, estimate the effectiveness each at decreasing gases impacts on quality stratospheric ozone. find that iron salt aerosol may not be effective reducing global scale, depending reaction mechanism employed. More work needed understand kinetics release from potential for bromine co-release, which further decreases effectiveness. Hydrogen peroxide–based approaches can methane, but hydrogen peroxide emissions required too large feasible. limiting daytime scenarios has negligible effects. All methods increase surface particulate matter (PM) pollution some regions lead exceedances annual standards. ozone pollution, OH-based populated areas. While substances, predict minimal changes after 1 year deployment. overall climate human health involve multiple competing factors.

Language: Английский

Citations

0
HOCl Formation Driven by Photochemical Processes Enhanced Atmospheric Oxidation Capacity in a Coastal Atmosphere DOI
Gaojie Chen, Xiaolong Fan,

Shaocai Yu

et al.

Environmental Science & Technology, Journal Year: 2025, Volume and Issue: unknown

Published: March 6, 2025

Chlorine (Cl) radicals can profoundly affect the atmospheric oxidation capacity and fates of pollutants. Hypochlorous acid (HOCl) is a potentially crucial Cl precursor, yet understanding its formation mechanisms impacts still limited. Here, we observed high concentrations HOCl in coastal city Southeast China during autumn 2022, with an average daytime peak 181 ppt. Machine learning analysis identified Cl2, O3, nitrate, temperature, iron as primary factors affecting distribution. Beyond Cl2 photolysis, both nitrate photolysis aerosol photochemistry also contributed to radical production, which drove production through reactions involving ClO HO2 presence O3. Both OH released via increased levels ROx by ∼10%, thereby enhancing O3 generation capacity. Our findings emphasize significant role chemistry suggest that controlling could alleviate adverse on air quality.

Language: Английский

Citations

0
Chlorine Activation in Marine Air: Insights From Chemical Budgets of Molecular Chlorine and Hypochlorous Acid DOI Creative Commons
Men Xia, Yifan Jiang, Jianing Dai

et al.

Journal of Geophysical Research Atmospheres, Journal Year: 2025, Volume and Issue: 130(6)

Published: March 11, 2025

Abstract Chlorine chemistry considerably affects air quality and climate in marine environments. Nitrogen oxides (NO x ), emitted by ocean‐going vessels, react with sea salt chloride to generate reactive chlorine species. However, the exact mechanisms chemical budget of remain poorly understood. In this study, we explore activation through field observations Hong Kong, complemented box modeling. Over 2‐week measurement period, summer monsoon introduced abundant NO , producing molecular (Cl 2 0.64 ± 0.69 ppt) hypochlorous acid (HOCl, 8.9 5.1 ppt). Daytime Cl production was attributable nitrate 3 − ) photolysis uptake on hydroxyl radicals (OH·) chloride‐containing aerosols. A analysis using model revealed that rate HOCl, primarily driven (ClONO hydrolysis, substantially lower than its loss rate. This discrepancy indicates either uncertainties known HOCl sources or a missing source atoms (Cl·). We examined potential precursors Cl· incorporating emerging species, such as, trichloramine (NCl iodine (ICl), into model. inclusion NCl caused an overestimation ambient levels, while adding ICl led excessive ozone (O depletion. Incorporating unknown (equivalent ∼46 ppt remarkably enhanced atmospheric oxidation capacity, increasing daytime OH· levels 12.8% net 35.7% decreasing mercury (Hg) lifetime factor 3. These findings highlight incomplete understanding suggest existence unidentified coastal

Language: Английский

Citations

0
Driving factors and photochemical impacts of Cl2 in coastal atmosphere of Southeast China DOI Creative Commons
Gaojie Chen,

Xiaolong Fan,

Ziyi Lin

et al.

npj Climate and Atmospheric Science, Journal Year: 2025, Volume and Issue: 8(1)

Published: April 2, 2025

Language: Английский

Citations

0
Dimethyl sulfide chemistry over the industrial era: comparison of key oxidation mechanisms and long-term observations DOI Creative Commons
Ursula A. Jongebloed, Jacob I. Chalif, Linia Tashmim

et al.

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(7), P. 4083 - 4106

Published: April 10, 2025

Abstract. Dimethyl sulfide (DMS) is primarily emitted by marine phytoplankton and oxidized in the atmosphere to form methanesulfonic acid (MSA) sulfate aerosols. Ice cores regions affected anthropogenic pollution show an industrial-era decline MSA, which has previously been interpreted as indicating a abundance. However, simultaneous increase DMS-derived (bioSO4) Greenland ice core suggests that pollution-driven oxidant changes caused MSA influencing relative production of versus bioSO4. Here we use GEOS-Chem, global chemical transport model, zero-dimensional box model over three time periods (preindustrial era, peak North Atlantic NOx pollution, 21st century) investigate drivers bioSO4, examine whether four DMS oxidation mechanisms reproduce trends seasonality observations. We find GEOS-Chem simulations can only partially bioSO4 wide variation results reflects sensitivity mechanism concentrations. Our support hypothesized nitrate radical industrial increases production, but competing factors such BrO result increased some simulations, inconsistent with To improve understanding oxidation, future work should aqueous-phase chemistry, produces 82 %–99 % our constrain atmospheric concentrations, including radical, hydroxyl reactive halogens.

Language: Английский

Citations

0