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<front>
<journal-meta>
<journal-id journal-id-type="publisher">EGUsphere</journal-id>
<journal-title-group>
<journal-title>EGUsphere</journal-title>
<abbrev-journal-title abbrev-type="publisher">EGUsphere</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">EGUsphere</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub"></issn>
<publisher><publisher-name>Copernicus Publications</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/egusphere-2026-3809</article-id>
<title-group>
<article-title>An Underappreciated Aqueous Pathway for Particle Oxidative Potential (OP): Mechanistic Insights into OP-Relevant Products from &amp;alpha;-Dicarbonyl and Reduced Nitrogen Reactions</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Pang</surname>
<given-names>Yulong</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Liu</surname>
<given-names>Fobang</given-names>
<ext-link>https://orcid.org/0000-0002-9914-165X</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Wang</surname>
<given-names>Yujing</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Zhang</surname>
<given-names>Xin</given-names>
<ext-link>https://orcid.org/0009-0009-1069-3481</ext-link>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Yang</surname>
<given-names>Xu</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Wang</surname>
<given-names>Yanan</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>He</surname>
<given-names>Chi</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Han</surname>
<given-names>Yuemei</given-names>
<ext-link>https://orcid.org/0000-0002-5044-8386</ext-link>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Nah</surname>
<given-names>Theodora</given-names>
<ext-link>https://orcid.org/0000-0002-8755-6153</ext-link>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Department of Environmental Science and Engineering, School of Energy and Power Engineering, Xi’an Jiaotong  University, Xi’an 710049, China</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Key Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061, China</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>School of Energy and Environment and State Key Laboratory of Marine Environmental Health, City University of  Hong Kong, Hong Kong SAR 999077, China</addr-line>
</aff>
<pub-date pub-type="epub">
<day>08</day>
<month>07</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>45</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Yulong Pang et al.</copyright-statement>
<copyright-year>2026</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-3809/">This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-3809/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-3809/egusphere-2026-3809.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-3809/egusphere-2026-3809.pdf</self-uri>
<abstract>
<p>Aqueous-phase reactions between &amp;alpha;-dicarbonyls and reduced nitrogen species represent an understudied pathway generating secondary organic aerosols that exhibit oxidative potential (OP). In this study, we investigated the OP of products formed from methylglyoxal (MG) or glyoxal (GX) reacting with ammonium sulfate (AS) or glycine (Gly) under varying pH (3&amp;ndash;7) and reaction times (4&amp;ndash;144 h). OP was quantified using dithiothreitol (DTT) depletion and hydroxyl radical (&amp;bull;OH) production assays, while molecular composition was characterized using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy. The results demonstrate that OP is strongly dependent on precursor identity, pH, and reaction time. Products from the MG+Gly system consistently exhibit the highest OP&lt;sup&gt;DTT&lt;/sup&gt; and OP&lt;sup&gt;OH&lt;/sup&gt;. Molecular analysis indicates that CHO species, including conjugated carbonyls and quinones, are primarily responsible for DTT activity, whereas N-heterocycles with unprotonated N-bases drive &amp;bull;OH formation. Electron-withdrawing substituents adjacent to the unprotonated N atoms enhance electron-transfer capability, thereby increasing the ability of N-heterocycles to generate &amp;bull;OH. N-heterocycles also act synergistically with quinone-like species to promote DTT oxidation, highlighting their dual role in modulating OP. Collectively, these findings reveal that aqueous reactions between &amp;alpha;-dicarbonyls and reduced nitrogen species can produce secondary organic aerosols with substantial oxidative capacity, which may contribute to oxidative stress and cause adverse health effects. This work advances mechanistic understanding of aerosol OP and emphasizes the importance of considering aqueous-phase chemistry when evaluating the health-relevant oxidative properties of ambient particulate matter.</p>
</abstract>
<counts><page-count count="45"/></counts>
<funding-group>
<award-group id="gs1">
<funding-source>National Natural Science Foundation of China</funding-source>
<award-id>42475111</award-id>
</award-group>
</funding-group>
</article-meta>
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