Dataset Information

Effect of OH scavengers on the chemical composition of α-pinene secondary organic aerosol.

ABSTRACT: OH scavengers are extensively used in studies of secondary organic aerosol (SOA) because they create an idealized environment where only a single oxidation pathway is occurring. Here, we present a detailed molecular characterization of SOA produced from α-pinene + O₃ with a variety of OH scavengers using the extractive electrospray time-of-flight mass spectrometer in our atmospheric simulation chamber, which is complemented by characterizing the gas phase composition in flow reactor experiments. Under our experimental conditions, radical chemistry largely controls the composition of SOA. Besides playing their desired role in suppressing the reaction of α-pinene with OH, OH scavengers alter the reaction pathways of radicals produced from α-pinene + O₃. This involves changing the HO₂ : RO₂ ratio, the identity of the RO₂ radicals present, and the RO₂ major sinks. As a result, the use of the OH scavengers has significant effects on the composition of SOA, including inclusions of scavenger molecules in SOA, the promotion of fragmentation reactions, and depletion of dimers formed via α-pinene RO₂-RO₂ reactions. To date fragmentation reactions and inclusion of OH scavenger products into secondary organic aerosol have not been reported in atmospheric simulation chamber studies. Therefore, care should be considered if and when to use an OH scavenger during experiments.

SUBMITTER: Bell DM

PROVIDER: S-EPMC9850668 | biostudies-literature | 2023 Jan

REPOSITORIES: biostudies-literature

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Effect of OH scavengers on the chemical composition of α-pinene secondary organic aerosol.

Bell David M DM Pospisilova Veronika V Lopez-Hilfiker Felipe F Bertrand Amelie A Xiao Mao M Zhou Xueqin X Huang Wei W Wang Dongyu S DS Lee Chuan Ping CP Dommen Josef J Baltensperger Urs U Prevot Andre S H ASH El Haddad Imad I Slowik Jay G JG

Environmental science: atmospheres 20221104 1

OH scavengers are extensively used in studies of secondary organic aerosol (SOA) because they create an idealized environment where only a single oxidation pathway is occurring. Here, we present a detailed molecular characterization of SOA produced from α-pinene + O<sub>3</sub> with a variety of OH scavengers using the extractive electrospray time-of-flight mass spectrometer in our atmospheric simulation chamber, which is complemented by characterizing the gas phase composition in flow reactor e ...[more]

PMID: 36743126

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Project description:Secondary organic aerosol (SOA) is a major component of airborne fine particulate matter (PM2.5) that contributes to adverse human health effects upon inhalation. Atmospheric ozonolysis of α-pinene, an abundantly emitted monoterpene from terrestrial vegetation, leads to significant global SOA formation; however, its impact on pulmonary pathophysiology remains uncertain. In this study, we quantified an increasing concentration response of three well-established α-pinene SOA tracers (pinic, pinonic, and 3-methyl-1,2,3-butanetricarboxylic acids) and a full mixture of α-pinene SOA in A549 (alveolar epithelial carcinoma) and BEAS-2B (bronchial epithelial normal) lung cell lines. The three aforementioned tracers contributed ∼57% of the α-pinene SOA mass under our experimental conditions. Cellular proliferation, cell viability, and oxidative stress were assessed as toxicological end points. The three α-pinene SOA molecular tracers had insignificant responses in both cell types when compared with the α-pinene SOA (up to 200 μg mL-1). BEAS-2B cells exposed to 200 μg mL-1 of α-pinene SOA decreased cellular proliferation to ∼70% and 44% at 24- and 48-h post exposure, respectively; no changes in A549 cells were observed. The inhibitory concentration-50 (IC50) in BEAS-2B cells was found to be 912 and 230 μg mL-1 at 24 and 48 h, respectively. An approximate 4-fold increase in cellular oxidative stress was observed in BEAS-2B cells when compared with untreated cells, suggesting that reactive oxygen species (ROS) buildup resulted in the downstream cytotoxicity following 24 h of exposure to α-pinene SOA. Organic hydroperoxides that were identified in the α-pinene SOA samples likely contributed to the ROS and cytotoxicity. This study identifies the potential components of α-pinene SOA that likely modulate the oxidative stress response within lung cells and highlights the need to carry out chronic exposure studies on α-pinene SOA to elucidate its long-term inhalation exposure effects.

Dataset Information

Effect of OH scavengers on the chemical composition of α-pinene secondary organic aerosol.

Publications

Effect of OH scavengers on the chemical composition of α-pinene secondary organic aerosol.

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