Assessing Regional Model Predictions of Wintertime SOA from Aromatic Compounds and Monoterpenes with Precursor-specific Tracers

Zhang, Jie; He, Xiao-Song; Gao, Yaqin; Zhu, Shuhui; Jing, Shengao; Wang, Hongli; Yu, Jian; Ying, Qi

doi:10.4209/aaqr.210233

Cited by 7 publications

(3 citation statements)

References 76 publications

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“…The SOA model has been simulated in regional and global scales to predict the contribution of SOA mass to the 45 total atmospheric organic aerosol (Zhang et al, 2021;Hodzic et al, 2015). The prediction of SOA formation has been approached by a conventional gas/particle partitioning of surrogate products (Odum et al, 1996) or the volatility basis set (VBS) approach (Donahue et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

CAMx-UNIPAR Simulation of SOA Mass Formed from Multiphase Reactions of Hydrocarbons under the Central Valley Urban Atmospheres of California

Jo¹,

Jang²,

Han³

et al. 2023

Preprint

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Abstract. The UNIfied Partitioning-Aerosol phase Reaction (UNIPAR) model was established on the Comprehensive Air quality Model with extensions (CAMx) to process Secondary Organic Aerosol (SOA) formation by capturing multiphase reactions of hydrocarbons (HCs) in regional scales. SOA growth was simulated using a wide range of anthropogenic HCs including ten aromatics and linear alkanes with different carbon-lengths. The atmospheric processes of biogenic HCs (isoprene, terpenes, and sesquiterpene) were simulated for the major oxidation paths (ozone, OH radicals, and nitrate radicals) to predict day and night SOA formation. The UNIPAR model streamlined the multiphase partitioning of the lumping species originating from semi-explicitly predicted gas products and their heterogeneous chemistry to form non-volatile oligomeric species in both organic aerosol and inorganic aqueous phase. The CAMx-UNIPAR model predicted SOA formation at four ground urban sites (San Jose, Sacramento, Fresno, and Bakersfield) in California, United States during wintertime 2018. Overall, the simulated mass concentrations of the total organic matter, consisting of primary OA (POA) and SOA, showed a good agreement with the observations. The simulated SOA mass in the urban areas of California was predominated by alkane and terpene. During the daytime, low-volatile products originating from the autoxidation of long-chain alkanes considerably contributed to the SOA mass. In contrast, a significant amount of nighttime SOA was produced by the reaction of terpene with ozone or nitrate radicals. The spatial distributions of anthropogenic SOA associated with aromatic and alkane HCs were noticeably affected by the southward wind direction owing to the relatively long lifetime of their atmospheric oxidation, whereas those of biogenic SOA were nearly insensitive to wind direction. During wintertime 2018, the impact of inorganic aerosol hygroscopicity on the total SOA budget was not evident because of the small contribution of aromatic and isoprene products that are hydrophilic and reactive in the inorganic aqueous phase. However, an increased isoprene SOA mass was predicted during the wet periods, although its contribution to the total SOA was little.

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Section: Introductionmentioning

confidence: 99%

CAMx-UNIPAR Simulation of SOA Mass Formed from Multiphase Reactions of Hydrocarbons under the Central Valley Urban Atmospheres of California

Jo¹,

Jang²,

Han³

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…In addition, there might be some differences in the environmental conditions between chamber and ambient air, which lead to different yields of tracer molecules. For instance, oligomer formation and aqueous-phase processes might not be considered in early chamber studies, which might result in the underestimation of SOA from certain precursors. ,, …”

Section: Resultsmentioning

confidence: 99%

“…For instance, oligomer formation and aqueousphase processes might not be considered in early chamber studies, which might result in the underestimation of SOA from certain precursors. 43,51,52 For the second possibility, potential interference from oligomerization of light aromatic VOCs during oxidation might lead to overestimation of SOA for heavy aromatic VOCs. Some dimeric or even trimeric aromatic OOMs might form during the oxidation of monoaromatic VOCs, which will be treated as heavy aromatic OOMs in the OOM-based method.…”

Section: Acs Earth Andmentioning

confidence: 99%

Underestimated Contribution of Heavy Aromatics to Secondary Organic Aerosol Revealed by Comparative Assessments Using New and Traditional Methods

Tian

Huang

Wang

et al. 2022

ACS Earth Space Chem.

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Oxygenated organic molecules (OOMs) from oxidation of volatile organic compounds (VOCs) are important contributors to secondary organic aerosol (SOA) formation. Recent field studies showed that anthropogenic precursors significantly contributed to OOMs and subsequent SOA formation in urban areas. We conducted collocated OOM measurements with nitrate-ion chemical ionization mass spectrometry and SOA molecular tracer measurements with thermal desorption aerosol gas chromatography–mass spectrometry in Shanghai. Using the newly developed OOM-based method, we found that OOMs derived from aromatic VOCs (aromatic OOMs) dominated the local SOA production with a contribution of 52%. The traditional SOA tracer-based method estimated a consistent fraction of 49% from monoaromatics and polyaromatics (e.g., naphthalene and methylnaphthalene). We further categorized the aromatic OOMs into heavy (carbon number: nC > 9) and light (nC = 6–9) ones primarily based on the ring number. Surprisingly, the contribution of heavy aromatic OOMs to SOA formation (25%) was more than twice of the naphthalene-derived SOA from the tracer-based method (10%). The gap could be explained by the fact that the OOM-based method also counted the contributions from other polyaromatic VOCs that are beyond methyl-/naphthalene. The high degrees of oxygenation caused by multistep oxidation and the higher carbon number (nC > 9) in heavy aromatic OOMs lead to their lower volatility and higher contributions to SOA. Our study provides previously unavailable linkage between the aromatic SOA with its precursors via simultaneous measurements of OOMs and molecular tracers, revealing the overlooked contribution from heavy aromatic VOCs to SOA formation.

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Modeling Secondary Organic Aerosols in China: State of the Art and Perspectives

Zhang

et al. 2023

Curr Pollution Rep

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Assessing Regional Model Predictions of Wintertime SOA from Aromatic Compounds and Monoterpenes with Precursor-specific Tracers

Cited by 7 publications

References 76 publications

CAMx-UNIPAR Simulation of SOA Mass Formed from Multiphase Reactions of Hydrocarbons under the Central Valley Urban Atmospheres of California

CAMx-UNIPAR Simulation of SOA Mass Formed from Multiphase Reactions of Hydrocarbons under the Central Valley Urban Atmospheres of California

Underestimated Contribution of Heavy Aromatics to Secondary Organic Aerosol Revealed by Comparative Assessments Using New and Traditional Methods

Modeling Secondary Organic Aerosols in China: State of the Art and Perspectives

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