Seasonal and diurnal variation of PM2.5 HULIS over Xi'an in Northwest China: Optical properties, chemical functional group, and relationship with reactive oxygen species (ROS)

Zhang, Tian; Huang, Shasha; Wang, Diwei; Sun, Jian; Zhang, Qian; Xu, Hongmei; Ho, Steven Sai Hang; Cao, Junji; Shen, Zhenxing

doi:10.1016/j.atmosenv.2021.118782

Cited by 30 publications

(8 citation statements)

References 85 publications

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“…In addition, an absorption peak at 1720 cm −1 was only present in the smallest particles with sizes of < 0.26 µm in summer, which was attributed to the unconjugated C=O stretching mainly of carbonyl carbon (Hu et al, 2019). A peak at 1641 cm −1 was also previously reported, which was attributed to conjugated carbonyl (C=O) groups and aromatic rings (C=C) (Zhang et al, 2022). A strong and sharp absorption at 1389 cm −1 is usually attributed to the C-H asymmetric bending vibrations of methyl groups in aliphatic chains (Duarte et al, 2007;Colthup, 2012).…”

Section: Functional Groups Analysis At Raw Phsupporting

confidence: 64%

Measurement report: Investigation of pH- and particle-size-dependent chemical and optical properties of water-soluble organic carbon: implications for its sources and aging processes

Qin

Qin²,

Wang³

et al. 2022

Atmos. Chem. Phys.

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Abstract. Knowledge of the chemical structures and optical properties of water-soluble organic carbon (WSOC) is critical considering its involvement in many key aerosol-associated chemical reactions and its potential impacts on climate radiative forcing. This study investigates the coupled effects of pH and particle size on the chemical structures (functional groups) and optical properties (UV/fluorescence properties) of WSOC and further explores the source and aging of WSOC constituents. The results showed that the specific UV absorbance at a wavelength of 254 nm (SUVA254) and mass absorption efficiency at a wavelength of 365 nm (MAE365) were higher in smaller than larger particles, revealing the relatively higher aromaticity/molecular weight and more freshness of WSOC in smaller particles. A decrease in aromaticity/molecular weight of WSOC in larger particles was caused by the degradation reaction that occurred during the aging process. The carboxylic groups tend to be enriched in larger particles, whereas the contribution of phenolic groups was generally higher in smaller particles. The changes in the fluorescence peak position suggested that hydroxyl groups play a leading role in pH-responsive fluorescence in summer, while carboxylic and nitro groups play a dominant role in winter. Overall, the chromophores in smaller particles showed a more pronounced pH dependence, which might be related to the higher content of aromatic species in WSOC in these particle size ranges. Specifically, the climate impact of WSOC would be enhanced with increasing pH. The pH- and particle-size-dependent chemical and optical properties of WSOC provide insights into the structure, source, and aging of WSOC, which will ultimately improve the accuracy of assessing the climate effects of WSOC.

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Section: Functional Groups Analysis At Raw Phsupporting

confidence: 64%

Measurement report: Investigation of pH- and particle-size-dependent chemical and optical properties of water-soluble organic carbon: implications for its sources and aging processes

Qin

Qin²,

Wang³

et al. 2022

Atmos. Chem. Phys.

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“…To unravel the chemical features of OOA contributing to cellular ROS production, we employed LC–MS/MS, FIGAERO-CIMS, and FT-IR spectrometry to characterize the molecular composition and functional groups in OA. It has been suggested that oxidized derivatives of aromatic compounds (e.g., quinone-type compounds) or conjugated double bonds (e.g., conjugated carbonyls) tend to induce cellular ROS production as they are known to participate in electron transfer reactions, which could result in ROS formation. ,, Thus, we categorized the compounds identified from LC–MS/MS and FIGAERO-CIMS analyses into four groups for each season, according to their DU/C, i.e., DU/C = 0, 0 < DU/C < 0.25, 0.25 ≤ DU/C < 0.5, and DU/C ≥ 0.5. This metric aims to represent the number of (equivalent) double bonds (e.g., CC, CO, and ring structure) in each carbon atom, such that DU/C = 0.5 would indicate one double bond shared by two carbon atoms on average.…”

Section: Resultsmentioning

confidence: 99%

Oxidized and Unsaturated: Key Organic Aerosol Traits Associated with Cellular Reactive Oxygen Species Production in the Southeastern United States

Liu,

Joo,

Ditto

et al. 2023

Environ. Sci. Technol.

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Exposure to ambient fine particulate matter (PM 2.5 ) is associated with millions of premature deaths annually. Oxidative stress through overproduction of reactive oxygen species (ROS) is a possible mechanism for PM 2.5 -induced health effects. Organic aerosol (OA) is a dominant component of PM 2.5 worldwide, yet its role in PM 2.5 toxicity is poorly understood due to its chemical complexity. Here, through integrated cellular ROS measurements and detailed multi-instrument chemical characterization of PM in urban southeastern United States, we show that oxygenated OA (OOA), especially more-oxidized OOA, is the main OA type associated with cellular ROS production. We further reveal that highly unsaturated species containing carbon–oxygen double bonds and aromatic rings in OOA are major contributors to cellular ROS production. These results highlight the key chemical features of ambient OA driving its toxicity. As more-oxidized OOA is ubiquitous and abundant in the atmosphere, this emphasizes the need to understand its sources and chemical processing when formulating effective strategies to mitigate PM 2.5 health impacts.

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“…Dithiothreitol (DTT) assay (Alam et al, 2013;Verma et al, 2015), as a non-cellular method, was widely employed to determine oxidation activity and OP of atmospheric PM (Chen et al, 2019;Cho et al, 2005) for the evaluation of its health effects. Some other works (Fang et al, 2016;McWhinney et al, 2013;Verma et al, 2015;Zhang et al, 2022) focused on the link between chemical components and OP in PM and confirmed that several kinds of compounds, such as quinones, HULIS, and transition metals usually had strong DTT activities. However, the DTT method has rarely been used to evaluate the OP of aqueous-phase oxidation products previously (Ou et al, 2021).…”

Section: Introductionmentioning

confidence: 80%

Optical and chemical properties and oxidative potential of aqueous-phase products from OH and <sup>3</sup>C<sup>∗</sup>-initiated photooxidation of eugenol

Tao

Zhu

et al. 2022

Atmos. Chem. Phys.

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Abstract. Aqueous reactions may turn precursors into light-absorbing and toxic products, leading to air quality deterioration and adverse health effects. In this study, we comprehensively investigated eugenol photooxidation (a representative biomass-burning-emitted, highly substituted phenolic compound) in the bulk aqueous phase with direct photolysis, a hydroxyl radical (OH), and an organic triplet excited state (3C∗). Results show that the degradation rates of eugenol followed the order of 3C∗> OH > direct photolysis. During the 3C∗-initiated oxidation, different reactive oxygen species (ROS), including 3C∗, OH, 1O2, and O2⚫-, can participate in the oxidation of eugenol, quenching experiments verified 3C∗ was the most important one, while, during OH-initiated oxidation, O2⚫- was a more important ROS than OH for degrading eugenol. The rate constants under saturated O2, air, and N2 followed the order of kO2>kAir>kN2 for both direct photolysis and OH-initiated oxidation but changed to kAir>kN2>kO2 for 3C∗-mediated oxidation. pH and dissolved oxygen (DO) levels both decreased during oxidation, indicating the formation of acids and the participation of DO in oxidation. Ultraviolet and visible (UV-vis) light absorption spectra of the reaction products showed a clear absorbance enhancement in the 300–400 nm range for all three sets of experiments, and new fluorescence at excitation/emission =250/ (400–500) nm appeared, suggesting the formation of new chromophores and fluorophores (brown carbon species). These species were likely attributed to humic-like substances (HULIS), as shown by the increases in HULIS concentrations during oxidation. Large mass yields of products (140 %–197 %) after 23 h of illumination were obtained, and high oxidation degrees of these products were also observed. Correspondingly, a series of oxygenated compounds were identified, and a detailed reaction mechanism with functionalization as a dominant pathway was proposed. At last, the dithiothreitol (DTT) assay was applied to assess the oxidation potential of the reaction products, and the end products of all three sets of experiments showed higher DTT consumption rates than those of eugenol, indicating that more toxic species were produced upon aqueous oxidation. Overall, our results from using eugenol as a model compound, underscore the potential importance of the aqueous processing of biomass burning emissions in secondary organic aerosol (SOA) formation.

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Seasonal and diurnal variation of PM2.5 HULIS over Xi'an in Northwest China: Optical properties, chemical functional group, and relationship with reactive oxygen species (ROS)

Cited by 30 publications

References 85 publications

Measurement report: Investigation of pH- and particle-size-dependent chemical and optical properties of water-soluble organic carbon: implications for its sources and aging processes

Measurement report: Investigation of pH- and particle-size-dependent chemical and optical properties of water-soluble organic carbon: implications for its sources and aging processes

Oxidized and Unsaturated: Key Organic Aerosol Traits Associated with Cellular Reactive Oxygen Species Production in the Southeastern United States

Optical and chemical properties and oxidative potential of aqueous-phase products from OH and <sup>3</sup>C<sup>∗</sup>-initiated photooxidation of eugenol

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Seasonal and diurnal variation of PM2.5 HULIS over Xi'an in Northwest China: Optical properties, chemical functional group, and relationship with reactive oxygen species (ROS)

Cited by 30 publications

References 85 publications

Measurement report: Investigation of pH- and particle-size-dependent chemical and optical properties of water-soluble organic carbon: implications for its sources and aging processes

Measurement report: Investigation of pH- and particle-size-dependent chemical and optical properties of water-soluble organic carbon: implications for its sources and aging processes

Oxidized and Unsaturated: Key Organic Aerosol Traits Associated with Cellular Reactive Oxygen Species Production in the Southeastern United States

Optical and chemical properties and oxidative potential of aqueous-phase products from OH and &lt;sup&gt;3&lt;/sup&gt;C&lt;sup&gt;∗&lt;/sup&gt;-initiated photooxidation of eugenol

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Optical and chemical properties and oxidative potential of aqueous-phase products from OH and <sup>3</sup>C<sup>∗</sup>-initiated photooxidation of eugenol