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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-2025-4662</article-id>
<title-group>
<article-title>Modification and validation of a commercial dynamic chamber for reactive nitrogen and greenhouse gas flux measurements</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Shah</surname>
<given-names>Moxy</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>Aregahegn</surname>
<given-names>Kifle</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>Nodeh-Farahani</surname>
<given-names>Danial</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>Crilley</surname>
<given-names>Leigh</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Hasan</surname>
<given-names>Tasnia</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>Ebrahimi-Iranpour</surname>
<given-names>Yashar</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>Sarker</surname>
<given-names>Fahim</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>Nickerson</surname>
<given-names>Nick</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Creelman</surname>
<given-names>Chance</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Ellis</surname>
<given-names>Sarah</given-names>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Moravek</surname>
<given-names>Alexander</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>VandenBoer</surname>
<given-names>Trevor</given-names>
<ext-link>https://orcid.org/0000-0001-8926-4237</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Department of Chemistry, York University, Toronto, Ontario, Canada</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Eosense Inc., Dartmouth, Nova Scotia, Canada</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>now at: Atmospheric Services, WSP Australia, Brisbane, QLD, Australia</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>now at: German Environment Agency, Department of Air Quality, Dessau-Rosslau, Germany</addr-line>
</aff>
<pub-date pub-type="epub">
<day>22</day>
<month>10</month>
<year>2025</year>
</pub-date>
<volume>2025</volume>
<fpage>1</fpage>
<lpage>59</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2025 Moxy Shah et al.</copyright-statement>
<copyright-year>2025</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/2025/egusphere-2025-4662/">This article is available from https://egusphere.copernicus.org/preprints/2025/egusphere-2025-4662/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2025/egusphere-2025-4662/egusphere-2025-4662.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2025/egusphere-2025-4662/egusphere-2025-4662.pdf</self-uri>
<abstract>
<p>Reactive nitrogen compounds (NO, NO&lt;sub&gt;2&lt;/sub&gt;, HONO, NH&lt;sub&gt;3&lt;/sub&gt; and others; N&lt;sub&gt;r&lt;/sub&gt;) play important roles in atmospheric processes, and their cascading impacts throughout the Earth system have adverse effects on both the environment and human health. The fluxes of these gases at the surface-atmosphere interface have been studied in isolation or in smaller subsets by micrometeorological techniques or chambers, but simultaneous observations of all N&lt;sub&gt;r&lt;/sub&gt; species alongside standard greenhouse gases (GHGs) as a function of time have not been reported. Here, a dual-dynamic chamber system was developed for N&lt;sub&gt;r&lt;/sub&gt; by modifying a commercially available system for GHG fluxes for use with destructive analyzers and to account for chemical changes. The resulting platform makes the measurement of N&lt;sub&gt;r&lt;/sub&gt; and, by extension other reactive gases, more widely accessible to the scientific community, as custom chambers do not need to be fabricated.&lt;/p&gt;
&lt;p&gt;System modifications to passivate surfaces were implemented, so that N&lt;sub&gt;r&lt;/sub&gt; gases like NO&lt;sub&gt;2&lt;/sub&gt; could be effectively transferred to standard gas analyzers, with an initial 36 % loss due to transformations ultimately minimized below analyzer detection limits (~10 %) under relevant atmospheric conditions. The modified 72 L chamber did not see a change in the baseline response times for GHGs or NO at a flow rate of 2 L min&lt;sup&gt;-1&lt;/sup&gt;. They retained the same values as an ideal non-reactive trace gas (&amp;tau; = 37&amp;ndash;39 min versus 36 min. The modifications improved the transfer time constants of NO&lt;sub&gt;2&lt;/sub&gt;, HONO, and NH&lt;sub&gt;3&lt;/sub&gt; by up to 2 min, but substantial surface interactions for NH&lt;sub&gt;3&lt;/sub&gt; remain. In all cases, a surface interaction term needs to be characterized for these gases to obtain accurate fluxes. Losses of NO&lt;sub&gt;2&lt;/sub&gt; and O&lt;sub&gt;3&lt;/sub&gt; by known gas phase reactions, or from deposition and reaction on pristine and aged chamber surfaces, were characterized across a range of environmentally relevant relative humidities (RH) and mixing ratios. The final dual-chamber system configuration includes a measurement and reference chamber, which are necessary to implement the corrections for surface effects and chemical transformations when accurately quantifying dynamic fluxes via a mass balance framework.&lt;/p&gt;
&lt;p&gt;Proof-of-concept measurements of N&lt;sub&gt;r&lt;/sub&gt; fluxes from agricultural soil samples under controlled lab conditions as a function of soil water content were able to quantify emissions of NO, NO&lt;sub&gt;2&lt;/sub&gt;, HONO, NH&lt;sub&gt;3&lt;/sub&gt;, and N&lt;sub&gt;2&lt;/sub&gt;O simultaneously, when subject to fertilization experiments using urea, ammonium carbonate and bicarbonate, and ammonium nitrate. Unfertilized replicate agricultural soil samples showed variability in NO&lt;sub&gt;2&lt;/sub&gt; and HONO emissions when prepared with minimal disturbance to the soil structure, with values consistent with those reported by in-situ field measurements. These oppose maximum potential fluxes characterized in prior lab soil manipulations, particularly for HONO relative to NO. Last, fluxes were quantified with destructive gas analyzers in the field with the dual-chamber system on an in-use agricultural soil and included a urea-based fertilizer perturbation to stimulate microbial and chemical transformation and transfer N&lt;sub&gt;r&lt;/sub&gt; to the atmosphere. The resulting fluxes observed show good agreement with prior reports based on other flux techniques. The mass balance terms within the dual-chamber approach are fully inspected from the pilot deployment in the field, along with an error analysis, to aid in the uptake of this approach by the community.</p>
</abstract>
<counts><page-count count="59"/></counts>
<funding-group>
<award-group id="gs1">
<funding-source>Natural Sciences and Engineering Research Council of Canada</funding-source>
<award-id>ALLRP 570577-2021</award-id>
<award-id>RGPIN-2020-06166</award-id>
<award-id>DGECR-2020-00186</award-id>
</award-group>
</funding-group>
</article-meta>
</front>
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