The number fraction of iron-containing particles affects OH, HO<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> budgets in the atmospheric aqueous phase
<p>Reactive oxygen species (ROS), such as OH, HO<span class="inline-formula"><sub>2</sub></span> and H<span class="inline-formula"><sub>2</sub></span>O<span class="inline-formula"><sub>2</sub></s...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2022-02-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/22/1989/2022/acp-22-1989-2022.pdf |
| _version_ | 1819274405341036544 |
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| author | A. Khaled M. Zhang M. Zhang B. Ervens |
| author_facet | A. Khaled M. Zhang M. Zhang B. Ervens |
| author_sort | A. Khaled |
| collection | DOAJ |
| description | <p>Reactive oxygen species (ROS), such as OH, HO<span class="inline-formula"><sub>2</sub></span> and H<span class="inline-formula"><sub>2</sub></span>O<span class="inline-formula"><sub>2</sub></span>, affect the oxidation capacity of the atmosphere and cause adverse health effects of particulate matter.
The role of transition metal ions (TMIs) in impacting the ROS concentrations and conversions in the atmospheric aqueous phase has been recognized for a long time.
Model studies usually assume that the total TMI mass as measured in bulk aerosol or cloud water samples is distributed equally across all particles or droplets.
This assumption is contrary to single-particle measurements that have shown that only a small number fraction of particles contain iron and other TMIs (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M7" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>F</mi><mrow class="chem"><mi mathvariant="normal">N</mi><mo>,</mo><mi mathvariant="normal">Fe</mi></mrow></msub><mo><</mo><mn mathvariant="normal">100</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="56pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="2c338a13422c4ae34d631f1b452830eb"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00001.svg" width="56pt" height="13pt" src="acp-22-1989-2022-ie00001.png"/></svg:svg></span></span> %), which implies that also not all cloud droplets contain TMIs.
In the current study, we apply a box model with an explicit multiphase chemical mechanism to simulate ROS formation and cycling in aqueous aerosol particles and cloud droplets.
Model simulations are performed for the range of 1 % <span class="inline-formula">≤</span> <span class="inline-formula"><i>F</i><sub>N,Fe</sub></span> <span class="inline-formula">≤</span> 100 % for constant pH values of 3, 4.5 and 6 and constant total iron mass concentration (10 or 50 ng per cubic meter of air). Model results are compared for two sets of simulations with <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M11" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>F</mi><mrow class="chem"><mi mathvariant="normal">N</mi><mo>,</mo><mi mathvariant="normal">Fe</mi></mrow></msub><mo><</mo><mn mathvariant="normal">100</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="56pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="218ae7c553115f032774e5ed1fbb167a"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00002.svg" width="56pt" height="13pt" src="acp-22-1989-2022-ie00002.png"/></svg:svg></span></span> % (FeN<span class="inline-formula"><</span>100) and 100 % (FeBulk). We find the largest differences between model results in OH and HO<span class="inline-formula"><sub>2</sub></span> <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M14" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="539a58614ea8688159b8effbc6d3da8d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00003.svg" width="8pt" height="14pt" src="acp-22-1989-2022-ie00003.png"/></svg:svg></span></span> O<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M15" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">2</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="605864571c3dcb0b6e3cb32dc4ee1961"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00004.svg" width="9pt" height="16pt" src="acp-22-1989-2022-ie00004.png"/></svg:svg></span></span> concentrations at pH <span class="inline-formula">=</span> 6. Under these conditions, HO<span class="inline-formula"><sub>2</sub></span> is subsaturated in the aqueous phase because of its high effective Henry's law constant and the fast chemical loss reactions of the O<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M18" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">2</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="e8d2895a9c589608e0a1b86f0f10fca1"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00005.svg" width="9pt" height="16pt" src="acp-22-1989-2022-ie00005.png"/></svg:svg></span></span> radical anion.
As the main reduction process of Fe(III) is its reaction with HO<span class="inline-formula"><sub>2</sub></span> <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M20" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="78c74280a32911099c6aadbec3864e34"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00006.svg" width="8pt" height="14pt" src="acp-22-1989-2022-ie00006.png"/></svg:svg></span></span> O<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M21" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">2</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="8d69e45fe59ebd0d6654b729518c066e"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00007.svg" width="9pt" height="16pt" src="acp-22-1989-2022-ie00007.png"/></svg:svg></span></span>, we show that the HO<span class="inline-formula"><sub>2</sub></span> subsaturation leads to Fe(II) <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M23" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="265e2a7d42d09da6c1e252e5649f9787"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00008.svg" width="8pt" height="14pt" src="acp-22-1989-2022-ie00008.png"/></svg:svg></span></span> Fe(total) ratios for <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M24" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>F</mi><mrow class="chem"><mi mathvariant="normal">N</mi><mo>,</mo><mi mathvariant="normal">Fe</mi></mrow></msub><mo><</mo><mn mathvariant="normal">100</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="56pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="bc93622d390dc02bd624c35a7ea2721c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00009.svg" width="56pt" height="13pt" src="acp-22-1989-2022-ie00009.png"/></svg:svg></span></span> % that are lower by a factor of <span class="inline-formula">≤</span> 2 as compared to bulk model approaches.
This trend is largely independent of the total iron concentration, as both chemical source and sink rates of HO<span class="inline-formula"><sub>2</sub></span> <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M27" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="69c0fe112c920c825e30a2abce4ab1e1"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00010.svg" width="8pt" height="14pt" src="acp-22-1989-2022-ie00010.png"/></svg:svg></span></span> O<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M28" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">2</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="8e914ad4168a57dc764c229ec74e2b30"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00011.svg" width="9pt" height="16pt" src="acp-22-1989-2022-ie00011.png"/></svg:svg></span></span> scale with the iron concentration.
We compare model-derived reactive uptake parameters <span class="inline-formula"><i>γ</i><sub>OH</sub></span> and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M30" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi mathvariant="italic">γ</mi><mrow class="chem"><msub><mi mathvariant="normal">HO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="12pt" class="svg-formula" dspmath="mathimg" md5hash="8b136d55403521e6f9ce747703af498c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00012.svg" width="24pt" height="12pt" src="acp-22-1989-2022-ie00012.png"/></svg:svg></span></span> for the full range of <span class="inline-formula"><i>F</i><sub>N,Fe</sub></span>. While <span class="inline-formula"><i>γ</i><sub>OH</sub></span> is not affected by the iron distribution, the calculated <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M33" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi mathvariant="italic">γ</mi><mrow class="chem"><msub><mi mathvariant="normal">HO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="12pt" class="svg-formula" dspmath="mathimg" md5hash="00377a211d011f682b67a44578446a91"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00013.svg" width="24pt" height="12pt" src="acp-22-1989-2022-ie00013.png"/></svg:svg></span></span> values range from 0.0004 to 0.03 for <span class="inline-formula"><i>F</i><sub>N,Fe</sub> </span>=<span class="inline-formula"> 1</span> % and 100 %, respectively.
Implications of these findings are discussed for the application of lab-derived <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M36" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi mathvariant="italic">γ</mi><mrow class="chem"><msub><mi mathvariant="normal">HO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="12pt" class="svg-formula" dspmath="mathimg" md5hash="96b4d23636922ea1119d9e231f96c943"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00014.svg" width="24pt" height="12pt" src="acp-22-1989-2022-ie00014.png"/></svg:svg></span></span> in models to present reactive HO<span class="inline-formula"><sub>2</sub></span> uptake on aerosols.
We conclude that the iron distribution (<span class="inline-formula"><i>F</i><sub>N,Fe</sub></span>) should be taken into account to estimate the ROS concentrations and oxidation potential of particulate matter that might be overestimated by bulk sampling and model approaches.
Our study suggests that the number concentration of iron-containing particles <span class="inline-formula"><i>F</i><sub>N,Fe</sub></span> may be more important than the total iron mass concentration in determining ROS budgets and uptake rates in cloud and aerosol water.</p> |
| first_indexed | 2024-12-23T23:07:54Z |
| format | Article |
| id | doaj.art-223c9b31065245d7bc85c92dfef8bc6f |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-23T23:07:54Z |
| publishDate | 2022-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-223c9b31065245d7bc85c92dfef8bc6f2022-12-21T17:26:45ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242022-02-01221989200910.5194/acp-22-1989-2022The number fraction of iron-containing particles affects OH, HO<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> budgets in the atmospheric aqueous phaseA. Khaled0M. Zhang1M. Zhang2B. Ervens3Université Clermont Auvergne, CNRS, SIGMA Clermont, Institut de Chimie de Clermont-Ferrand, 63000 Clermont-Ferrand, FranceUniversité Clermont Auvergne, CNRS, SIGMA Clermont, Institut de Chimie de Clermont-Ferrand, 63000 Clermont-Ferrand, Francenow at: Plair SA, Route de Saint-Julien 275, Perly 1258, SwitzerlandUniversité Clermont Auvergne, CNRS, SIGMA Clermont, Institut de Chimie de Clermont-Ferrand, 63000 Clermont-Ferrand, France<p>Reactive oxygen species (ROS), such as OH, HO<span class="inline-formula"><sub>2</sub></span> and H<span class="inline-formula"><sub>2</sub></span>O<span class="inline-formula"><sub>2</sub></span>, affect the oxidation capacity of the atmosphere and cause adverse health effects of particulate matter. The role of transition metal ions (TMIs) in impacting the ROS concentrations and conversions in the atmospheric aqueous phase has been recognized for a long time. Model studies usually assume that the total TMI mass as measured in bulk aerosol or cloud water samples is distributed equally across all particles or droplets. This assumption is contrary to single-particle measurements that have shown that only a small number fraction of particles contain iron and other TMIs (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M7" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>F</mi><mrow class="chem"><mi mathvariant="normal">N</mi><mo>,</mo><mi mathvariant="normal">Fe</mi></mrow></msub><mo><</mo><mn mathvariant="normal">100</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="56pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="2c338a13422c4ae34d631f1b452830eb"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00001.svg" width="56pt" height="13pt" src="acp-22-1989-2022-ie00001.png"/></svg:svg></span></span> %), which implies that also not all cloud droplets contain TMIs. In the current study, we apply a box model with an explicit multiphase chemical mechanism to simulate ROS formation and cycling in aqueous aerosol particles and cloud droplets. Model simulations are performed for the range of 1 % <span class="inline-formula">≤</span> <span class="inline-formula"><i>F</i><sub>N,Fe</sub></span> <span class="inline-formula">≤</span> 100 % for constant pH values of 3, 4.5 and 6 and constant total iron mass concentration (10 or 50 ng per cubic meter of air). Model results are compared for two sets of simulations with <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M11" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>F</mi><mrow class="chem"><mi mathvariant="normal">N</mi><mo>,</mo><mi mathvariant="normal">Fe</mi></mrow></msub><mo><</mo><mn mathvariant="normal">100</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="56pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="218ae7c553115f032774e5ed1fbb167a"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00002.svg" width="56pt" height="13pt" src="acp-22-1989-2022-ie00002.png"/></svg:svg></span></span> % (FeN<span class="inline-formula"><</span>100) and 100 % (FeBulk). We find the largest differences between model results in OH and HO<span class="inline-formula"><sub>2</sub></span> <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M14" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="539a58614ea8688159b8effbc6d3da8d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00003.svg" width="8pt" height="14pt" src="acp-22-1989-2022-ie00003.png"/></svg:svg></span></span> O<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M15" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">2</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="605864571c3dcb0b6e3cb32dc4ee1961"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00004.svg" width="9pt" height="16pt" src="acp-22-1989-2022-ie00004.png"/></svg:svg></span></span> concentrations at pH <span class="inline-formula">=</span> 6. Under these conditions, HO<span class="inline-formula"><sub>2</sub></span> is subsaturated in the aqueous phase because of its high effective Henry's law constant and the fast chemical loss reactions of the O<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M18" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">2</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="e8d2895a9c589608e0a1b86f0f10fca1"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00005.svg" width="9pt" height="16pt" src="acp-22-1989-2022-ie00005.png"/></svg:svg></span></span> radical anion. As the main reduction process of Fe(III) is its reaction with HO<span class="inline-formula"><sub>2</sub></span> <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M20" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="78c74280a32911099c6aadbec3864e34"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00006.svg" width="8pt" height="14pt" src="acp-22-1989-2022-ie00006.png"/></svg:svg></span></span> O<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M21" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">2</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="8d69e45fe59ebd0d6654b729518c066e"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00007.svg" width="9pt" height="16pt" src="acp-22-1989-2022-ie00007.png"/></svg:svg></span></span>, we show that the HO<span class="inline-formula"><sub>2</sub></span> subsaturation leads to Fe(II) <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M23" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="265e2a7d42d09da6c1e252e5649f9787"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00008.svg" width="8pt" height="14pt" src="acp-22-1989-2022-ie00008.png"/></svg:svg></span></span> Fe(total) ratios for <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M24" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>F</mi><mrow class="chem"><mi mathvariant="normal">N</mi><mo>,</mo><mi mathvariant="normal">Fe</mi></mrow></msub><mo><</mo><mn mathvariant="normal">100</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="56pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="bc93622d390dc02bd624c35a7ea2721c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00009.svg" width="56pt" height="13pt" src="acp-22-1989-2022-ie00009.png"/></svg:svg></span></span> % that are lower by a factor of <span class="inline-formula">≤</span> 2 as compared to bulk model approaches. This trend is largely independent of the total iron concentration, as both chemical source and sink rates of HO<span class="inline-formula"><sub>2</sub></span> <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M27" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="69c0fe112c920c825e30a2abce4ab1e1"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00010.svg" width="8pt" height="14pt" src="acp-22-1989-2022-ie00010.png"/></svg:svg></span></span> O<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M28" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">2</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="9pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="8e914ad4168a57dc764c229ec74e2b30"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00011.svg" width="9pt" height="16pt" src="acp-22-1989-2022-ie00011.png"/></svg:svg></span></span> scale with the iron concentration. We compare model-derived reactive uptake parameters <span class="inline-formula"><i>γ</i><sub>OH</sub></span> and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M30" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi mathvariant="italic">γ</mi><mrow class="chem"><msub><mi mathvariant="normal">HO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="12pt" class="svg-formula" dspmath="mathimg" md5hash="8b136d55403521e6f9ce747703af498c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00012.svg" width="24pt" height="12pt" src="acp-22-1989-2022-ie00012.png"/></svg:svg></span></span> for the full range of <span class="inline-formula"><i>F</i><sub>N,Fe</sub></span>. While <span class="inline-formula"><i>γ</i><sub>OH</sub></span> is not affected by the iron distribution, the calculated <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M33" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi mathvariant="italic">γ</mi><mrow class="chem"><msub><mi mathvariant="normal">HO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="12pt" class="svg-formula" dspmath="mathimg" md5hash="00377a211d011f682b67a44578446a91"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00013.svg" width="24pt" height="12pt" src="acp-22-1989-2022-ie00013.png"/></svg:svg></span></span> values range from 0.0004 to 0.03 for <span class="inline-formula"><i>F</i><sub>N,Fe</sub> </span>=<span class="inline-formula"> 1</span> % and 100 %, respectively. Implications of these findings are discussed for the application of lab-derived <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M36" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi mathvariant="italic">γ</mi><mrow class="chem"><msub><mi mathvariant="normal">HO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="12pt" class="svg-formula" dspmath="mathimg" md5hash="96b4d23636922ea1119d9e231f96c943"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-1989-2022-ie00014.svg" width="24pt" height="12pt" src="acp-22-1989-2022-ie00014.png"/></svg:svg></span></span> in models to present reactive HO<span class="inline-formula"><sub>2</sub></span> uptake on aerosols. We conclude that the iron distribution (<span class="inline-formula"><i>F</i><sub>N,Fe</sub></span>) should be taken into account to estimate the ROS concentrations and oxidation potential of particulate matter that might be overestimated by bulk sampling and model approaches. Our study suggests that the number concentration of iron-containing particles <span class="inline-formula"><i>F</i><sub>N,Fe</sub></span> may be more important than the total iron mass concentration in determining ROS budgets and uptake rates in cloud and aerosol water.</p>https://acp.copernicus.org/articles/22/1989/2022/acp-22-1989-2022.pdf |
| spellingShingle | A. Khaled M. Zhang M. Zhang B. Ervens The number fraction of iron-containing particles affects OH, HO<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> budgets in the atmospheric aqueous phase Atmospheric Chemistry and Physics |
| title | The number fraction of iron-containing particles affects OH, HO<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> budgets in the atmospheric aqueous phase |
| title_full | The number fraction of iron-containing particles affects OH, HO<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> budgets in the atmospheric aqueous phase |
| title_fullStr | The number fraction of iron-containing particles affects OH, HO<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> budgets in the atmospheric aqueous phase |
| title_full_unstemmed | The number fraction of iron-containing particles affects OH, HO<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> budgets in the atmospheric aqueous phase |
| title_short | The number fraction of iron-containing particles affects OH, HO<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> budgets in the atmospheric aqueous phase |
| title_sort | number fraction of iron containing particles affects oh ho sub 2 sub and h sub 2 sub o sub 2 sub budgets in the atmospheric aqueous phase |
| url | https://acp.copernicus.org/articles/22/1989/2022/acp-22-1989-2022.pdf |
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