the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 25 Nov 2025
Multiphase reactions of aromatic organosulfates with OH radicals: Kinetics, mechanisms, and environmental effects
Abstract. Aromatic organosulfates (aromatic OSs) are widely detected in the atmosphere and exhibit high abundance in urban areas. However, the atmospheric fate and environmental impacts of aromatic OSs remain poorly understood. In this study, we investigated the multiphase reaction of three aromatic OS (i.e., phenyl sulfate, p-tolyl sulfate, and 4-ethylphenyl sulfate) with OH radicals. The second-order reaction rate constant (k) of aromatic OSs with OH radicals were measured in the range of 4.29–6.38×109 M–1 s–1 at different pHs. It is found that k values are similar for the homologues of aromatic OSs, whereas are slightly affected by the solution pH values. The multiphase reactions of aromatic OSs and OH radicals mainly yield functionalized OSs, along with fragmented OSs and inorganic sulfate. The observation of inorganic sulfate formation, for the first time, indicates that aromatic OSs can also be converted into inorganic sulfate in analogues to aliphatic OSs. Furthermore, generated chromophores and fluorophores (constituents of brown carbon, BrC) products can significantly enhance the light absorption capacity, particularly under acidic conditions. These findings provide new insights into the understanding of the fate of aromatic OSs in the atmosphere that they can rapidly undergo atmospheric transformation, affecting the atmospheric sulfur cycle and altering aerosol optical properties.
- Preprint
(749 KB) - Metadata XML
-
Supplement
(579 KB) - BibTeX
- EndNote
Status: open (until 06 Jan 2026)
- RC1: 'Comment on egusphere-2025-5606', Anonymous Referee #1, 13 Dec 2025 reply
Viewed
| HTML | XML | Total | Supplement | BibTeX | EndNote | |
|---|---|---|---|---|---|---|
| 110 | 30 | 11 | 151 | 14 | 12 | 11 |
- HTML: 110
- PDF: 30
- XML: 11
- Total: 151
- Supplement: 14
- BibTeX: 12
- EndNote: 11
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1
Yang et al. investigated the multiphase reaction of aromatic organosulfates with OH radicals, providing pH dependent rate constants, organosulfate products, and produced inorganic sulfate. The authors additionally show evidence for increased absorbance in OS reaction products. The main kinetically related goals of this manuscript are closely related to that of Gweme and Styler (2024) (referenced by the authors). And indeed, these authors find good agreement between their kinetic results and those from Gweme and Styler (2024). But at least as worded in the introduction, the authors suggest that the novelty and necessity of their new study here is to investigate the possibility of inorganic sulfate as a product (something Gweme and Styler did not provide evidence for, at least for aromatic organosulfates). I have concerns about the experimental design and quality control related to their observation of inorganic sulfate as described below. Recent work from their own institution on inorganic sulfate products is also not referenced (https://acp.copernicus.org/articles/25/8575/2025/). I have listed my concerns below, which largely pertain to novelty and need for increased experimental evidence in some cases. Overall, I believe that my concerns should be addressed before I can recommend publication.
Line 35-36: This statement is unsupported and too speculative for an introduction.
Line 51: No need to say ‘potential’ – Hydrolysis is indeed known to removed OSs.
Line 54: …radicals that reacted…
Line 57: “border kind” is at least an unfamiliar term to me, consider using something else
Line 63: “… the partial of OSs…” is confusing as written
Lines 65 – 70: No reference is given for this. Please correct, as the authors seem to use this evidence as the paramount motivation for their study here. Presumably this is Gweme and Styler (2024), but it isn’t confirmed.
Line 88: Is this a summed concentration? Or for each individual component?
Line 96 – 97: This statement needs experimental or referenced support. Even though I appreciate that hydrolysis of aromatic organosulfates is slow, it is critical that the authors make it defensible beyond doubt that hydrolysis isn’t a kinetically meaningful contributor to their aqueous phase analyses.
Line 122: Change ‘spectrometry’ to ‘spectrometer’
Line 150: Missing superscript formatting
Line 196: Typo for ‘radical’
Line 202-203: This is more interesting to me than the motivation that was framed in the introduction
Line 213: Did the authors conduct any full scan mass spectrometry acquisitions of individual organosulfate standards? The detection of m/z 97 does not exclusively indicate inorganic sulfate, as it may also be the result of in-source fragmentation of their organosulfate standards. While electrospray ionization is soft, is still doesn’t eliminate the possibility of such byproduct fragments formed from organic precursors. This needs to be clarified in detail.
Line 225 – 227: If the authors cannot adequately defend their observations (especially for a chemical product that is so important to their studies motivations and novelty), then it should not be included in the manuscript.
Line 228: I’m not sure this is true as written. Again, I need to see more quality control experiments of the standards themselves to be sure of what the exact origin is of the author’s inorganic sulfate peak.
Line 243 – 244: This is vague and unspecific. Statements such as this are best introduced in the introduction with referenced support.
Line 250: This is just my opinion, but descriptors like ‘remarkable’ don’t offer much for a scientific observation. What exactly makes it ‘remarkable?’
Section 3.3: The authors talk about the formation of brown carbon species. They do not provide molecular-level data to better defend this observation despite having the capability to do so (i.e., a high-resolution mass spectrometry system). There are indeed interesting and exciting observations reported in this paragraph. But while they do have the absorbance data, some molecular-level evaluation of these formed compounds would be much more convincing and comprehensive to defend/prove these observations. This type of data, if acquired, should then also be featured in a key manuscript figure.
Figure 4: Please be more descriptive (i.e., avoid acronyms) whenever possible in figure captions and axes. While I hope that most don’t just look at figures, many inevitably do, so it is best to avoid acronyms as much as possible.