1
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Zhou L, Liang Z, Qin Y, Chan CK. Evaporation-Induced Transformations in Volatile Chemical Product-Derived Secondary Organic Aerosols: Browning Effects and Alterations in Oxidative Reactivity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:11105-11117. [PMID: 38866390 PMCID: PMC11210209 DOI: 10.1021/acs.est.4c02316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 05/15/2024] [Accepted: 05/21/2024] [Indexed: 06/14/2024]
Abstract
Volatile chemical products (VCPs) are increasingly recognized as significant sources of volatile organic compounds (VOCs) in urban atmospheres, potentially serving as key precursors for secondary organic aerosol (SOA) formation. This study investigates the formation and physicochemical transformations of VCP-derived SOA, produced through ozonolysis of VOCs evaporated from a representative room deodorant air freshener, focusing on the effects of aerosol evaporation on its molecular composition, light absorption properties, and reactive oxygen species (ROS) generation. Following aerosol evaporation, solutes become concentrated, accelerating reactions within the aerosol matrix that lead to a 42% reduction in peroxide content and noticeable browning of the SOA. This process occurs most effectively at moderate relative humidity (∼40%), reaching a maximum solute concentration before aerosol solidification. Molecular characterization reveals that evaporating VCP-derived SOA produces highly conjugated nitrogen-containing products from interactions between existing or transformed carbonyl compounds and reduced nitrogen species, likely acting as chromophores responsible for the observed brownish coloration. Additionally, the reactivity of VCP-derived SOA was elucidated through heterogeneous oxidation of sulfur dioxide (SO2), which revealed enhanced photosensitized sulfate production upon drying. Direct measurements of ROS, including singlet oxygen (1O2), superoxide (O2•-), and hydroxyl radicals (•OH), showed higher abundances in dried versus undried SOA samples under light exposure. Our findings underscore that drying significantly alters the physicochemical properties of VCP-derived SOA, impacting their roles in atmospheric chemistry and radiative balance.
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Affiliation(s)
- Liyuan Zhou
- Division
of Physical Sciences and Engineering, King
Abdullah University of Science and Technology, Thuwal, Jeddah 23955-6900, Kingdom
of Saudi Arabia
- School
of Energy and Environment, City University
of Hong Kong, Tat Chee Avenue, Kowloon 999077, Hong Kong SAR, China
| | - Zhancong Liang
- Division
of Physical Sciences and Engineering, King
Abdullah University of Science and Technology, Thuwal, Jeddah 23955-6900, Kingdom
of Saudi Arabia
| | - Yiming Qin
- School
of Energy and Environment, City University
of Hong Kong, Tat Chee Avenue, Kowloon 999077, Hong Kong SAR, China
| | - Chak K. Chan
- Division
of Physical Sciences and Engineering, King
Abdullah University of Science and Technology, Thuwal, Jeddah 23955-6900, Kingdom
of Saudi Arabia
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2
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Brunet C, Marek RF, Stanier CO, Hornbuckle KC. Concentrations of Volatile Methyl Siloxanes in New York City Reflect Emissions from Personal Care and Industrial Use. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:8835-8845. [PMID: 38722766 PMCID: PMC11112754 DOI: 10.1021/acs.est.3c10752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 04/25/2024] [Accepted: 04/26/2024] [Indexed: 05/22/2024]
Abstract
Volatile methyl siloxanes (VMS) are a group of organosilicon compounds of interest because of their potential health effects, their ability to form secondary organic aerosols, and their use as tracer compounds. VMS are emitted in the gas-phase from using consumer and personal care products, including deodorants, lotions, and hair conditioners. Because of this emission route, airborne concentrations are expected to increase with population density, although there are few studies in large urban centers. Here, we report summertime concentrations and daily variations of VMS congeners measured in New York City. Median concentrations of the 6 studied congeners, D3 (20 ng m-3), D4 (57 ng m-3), D5 (230 ng m-3), D6 (11 ng m-3), L5 (2.5 ng m-3), and L7 (1.3 ng m-3) are among the highest reported outdoor concentrations in the literature to date. Average congener ratios of D5:D4 and D5:D6 were consistent with previously reported emissions ratios, suggesting that concentrations were dominated by local emissions. Measured concentrations agree with previously published results from a Community Multiscale Air Quality model and support commonly accepted emissions rates for D4, D5, and D6 of 32.8, 135, and 6.1 mg per capita per day. Concentrations of D4, D5, D6, L5, and L7 and total VMS were significantly lower during the day than during the night, consistent with daytime oxidation reactivity. Concentrations of D3 did not show the same diurnal trend but exhibited a strong directional dependence, suggesting that it may be emitted by industrial point sources in the area rather than personal care product use. Concentrations of all congeners had large temporal variations but showed relatively weak relationships with wind speed, temperature, and mixing height.
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Affiliation(s)
- Christopher
E. Brunet
- Department
of Civil and Environmental Engineering, IIHR-Hydroscience & Engineering, University of Iowa, Iowa City Iowa 52242, United States
| | - Rachel F. Marek
- Department
of Civil and Environmental Engineering, IIHR-Hydroscience & Engineering, University of Iowa, Iowa City Iowa 52242, United States
| | - Charles O. Stanier
- Department
of Chemical and Biochemical Engineering, IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City Iowa 52242, United States
| | - Keri C. Hornbuckle
- Department
of Civil and Environmental Engineering, IIHR-Hydroscience & Engineering, University of Iowa, Iowa City Iowa 52242, United States
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3
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Meepage J, Welker JK, Meyer CM, Mohammadi S, Stanier CO, Stone EA. Advances in the Separation and Detection of Secondary Organic Aerosol Produced by Decamethylcyclopentasiloxane (D 5) in Laboratory-Generated and Ambient Aerosol. ACS ES&T AIR 2024; 1:365-375. [PMID: 38751609 PMCID: PMC11091883 DOI: 10.1021/acsestair.3c00073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 03/13/2024] [Accepted: 03/14/2024] [Indexed: 05/18/2024]
Abstract
Decamethylcyclopentasiloxane (D5), a common ingredient in many personal care products (PCPs), undergoes oxidation in the atmosphere, leading to the formation of secondary organic aerosol (SOA). Yet, the specific contributions of D5-derived SOA on ambient fine particulate matter (PM2.5) have not been characterized. This study addresses this knowledge gap by introducing a new analytical method to advance the molecular characterization of oxidized D5 and its detection in ambient aerosol. The newly developed reversed phase liquid chromatography method, in conjunction with high-resolution mass spectrometry, separates and detects D5 oxidation products, enabling new insights into their molecular and isomeric composition. Application of this method to laboratory-generated SOA and urban PM2.5 in New York City expands the number of D5 oxidation products observed in ambient aerosol and informs a list of molecular candidates to track D5-derived SOA in the atmosphere. An oxidation series was observed in which one or more methyl groups in D5 (C10H30O5Si5) is replaced by a hydroxyl group, which indicates the presence of multistep oxidation products in ambient PM2.5. Because of their specificity to PCPs and demonstrated detectability in ambient PM2.5, several oxidation products are proposed as molecular tracers for D5-derived SOA and may prove useful in assessing the impact of PCPs-derived SOA in the atmosphere.
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Affiliation(s)
- Jeewani
N. Meepage
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Josie K. Welker
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Claire M. Meyer
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Saeideh Mohammadi
- Department
of Chemical and Biochemical Engineering, University of Iowa, Iowa City, Iowa 52242, United States
| | - Charles O. Stanier
- Department
of Chemical and Biochemical Engineering, University of Iowa, Iowa City, Iowa 52242, United States
| | - Elizabeth A. Stone
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
- Department
of Chemical and Biochemical Engineering, University of Iowa, Iowa City, Iowa 52242, United States
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4
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Sasidharan S, He Y, Akherati A, Li Q, Li W, Cocker D, McDonald BC, Coggon MM, Seltzer KM, Pye HOT, Pierce JR, Jathar SH. Secondary Organic Aerosol Formation from Volatile Chemical Product Emissions: Model Parameters and Contributions to Anthropogenic Aerosol. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:11891-11902. [PMID: 37527511 DOI: 10.1021/acs.est.3c00683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
Volatile chemical products (VCP) are an increasingly important source of hydrocarbon and oxygenated volatile organic compound (OVOC) emissions to the atmosphere, and these emissions are likely to play an important role as anthropogenic precursors for secondary organic aerosol (SOA). While the SOA from VCP hydrocarbons is often accounted for in models, the formation, evolution, and properties of SOA from VCP OVOCs remain uncertain. We use environmental chamber data and a kinetic model to develop SOA parameters for 10 OVOCs representing glycols, glycol ethers, esters, oxygenated aromatics, and amines. Model simulations suggest that the SOA mass yields for these OVOCs are of the same magnitude as widely studied SOA precursors (e.g., long-chain alkanes, monoterpenes, and single-ring aromatics), and these yields exhibit a linear correlation with the carbon number of the precursor. When combined with emissions inventories for two megacities in the United States (US) and a US-wide inventory, we find that VCP VOCs react with OH to form 0.8-2.5× as much SOA, by mass, as mobile sources. Hydrocarbons (terpenes, branched and cyclic alkanes) and OVOCs (terpenoids, glycols, glycol ethers) make up 60-75 and 25-40% of the SOA arising from VCP use, respectively. This work contributes to the growing body of knowledge focused on studying VCP VOC contributions to urban air pollution.
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Affiliation(s)
- Sreejith Sasidharan
- Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Yicong He
- Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
- State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China
| | - Ali Akherati
- Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Qi Li
- Chemical and Environmental Engineering, University of California Riverside, Riverside, California 92521, United States
| | - Weihua Li
- Chemical and Environmental Engineering, University of California Riverside, Riverside, California 92521, United States
| | - David Cocker
- Chemical and Environmental Engineering, University of California Riverside, Riverside, California 92521, United States
| | - Brian C McDonald
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, United States
| | - Matthew M Coggon
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado 80305, United States
| | - Karl M Seltzer
- Office of Air and Radiation, Environmental Protection Agency, Research Triangle Park, North Carolina 27709, United States
| | - Havala O T Pye
- Office of Research and Development, Environmental Protection Agency, Research Triangle Park, North Carolina 27709, United States
| | - Jeffrey R Pierce
- Atmospheric Science, Colorado State University, Fort Collins, Colorado 80521, United States
| | - Shantanu H Jathar
- Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, United States
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5
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Jaoui M, Docherty KS, Lewandowski M, Kleindienst TE. Yields and molecular composition of gas phase and secondary organic aerosol from the photooxidation of the volatile consumer product benzyl alcohol: formation of highly oxygenated and hydroxy nitroaromatic compounds. ATMOSPHERIC CHEMISTRY AND PHYSICS 2023; 23:4637-4661. [PMID: 38361764 PMCID: PMC10866305 DOI: 10.5194/acp-23-4637-2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Recently, volatile chemical products (VCPs) have been increasingly recognized as important precursors for secondary organic aerosol (SOA) and ozone in urban areas. However, their atmospheric chemistry, physical transformation, and their impact on climate, environment and human health remain poorly understood. Here, the yields and chemical composition at the molecular level of gas and particle phase products originating from the photooxidation of one of these VCPs, benzyl alcohol (BnOH), is reported. The SOA was generated in the presence of seed aerosol from nebulized ammonium sulfate solution in a 14.5 m3 smog chamber operated in flow mode. More than 50 organic compounds containing nitrogen and/or up to seven oxygen atoms were identified by mass spectrometry. While a detailed non-targeted analysis has been made, our primary focus has been to examine highly oxygenated and nitro-aromatic compounds. The major components include ring-opening products with high oxygen to carbon ratio (e.g., malic acid, tartaric acids, arabic acid, trihydroxy-oxo-pentanoic acids, and pentaric acid), and ring-retaining products (e.g., benzaldehyde, benzoic acid, catechol, 3-nitrobenzyl alcohol, 4-nitrocatechol, 2-hydroxy-5-nitrobenzyl alcohol, 2-nitrophloroglucinol, 3,4-dihydroxy-5-nitrobenzyl alcohol). The presence of some of these products in the gas and particle phases simultaneously provides evidence of their gas/particle partitioning. These oxygenated oxidation products made dominant contributions to the SOA particle composition in both low and high NOx systems. Yields, organic mass to organic carbon ratio, and proposed reaction schemes for selected compounds are provided. The aerosol yield was 5.2% for BnOH/H2O2 at SOA concentration of 52.9 µg m-3 and ranged between 1.7-8.1 % for BnOH/NOx at SOA concentration of 40.0-119.5 µg m-3.
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Affiliation(s)
- Mohammed Jaoui
- Center for Environmental Measurement & Modeling, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | | | - Michael Lewandowski
- Center for Environmental Measurement & Modeling, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
| | - Tadeusz E. Kleindienst
- Center for Environmental Measurement & Modeling, U.S. Environmental Protection Agency, Research Triangle Park, NC, 27711, USA
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6
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Alton MW, Browne EC. Atmospheric Degradation of Cyclic Volatile Methyl Siloxanes: Radical Chemistry and Oxidation Products. ACS ENVIRONMENTAL AU 2022; 2:263-274. [PMID: 37102141 PMCID: PMC10114625 DOI: 10.1021/acsenvironau.1c00043] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Cyclic volatile methyl siloxanes (cVMS) are anthropogenic chemicals that have come under scrutiny due to their widespread use and environmental persistence. Significant data on environmental concentrations and persistence of these chemicals exists, but their oxidation mechanism is poorly understood, preventing a comprehensive understanding of the environmental fate and impact of cVMS. We performed experiments in an environmental chamber to characterize the first-generation oxidation products of hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5) under different peroxy radical fates (unimolecular reaction or bimolecular reaction with either NO or HO2) that approximate a range of atmospheric compositions. While the identity of the oxidation products from D3 changed as a function of the peroxy radical fate, the identity and yield of D4 and D5 oxidation products remained largely constant. We compare our results against the output from a kinetic model of cVMS oxidation chemistry. The reaction mechanism used in the model is developed using a combination of previously proposed cVMS oxidation reactions and standard atmospheric oxidation radical chemistry. We find that the model is unable to reproduce our measurements, particularly in the case of D4 and D5. The products that are poorly represented in the model help to identify possible branching points in the mechanism, which require further investigation. Additionally, we estimated the physical properties of the cVMS oxidation products using structure-activity relationships and found that they should not be significantly partitioned to organic or aqueous aerosol. The results suggest that cVMS first-generation oxidation products are also long-lived in the atmosphere and that environmental monitoring of these compounds is necessary to understand the environmental chemistry and loading of cVMS.
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Affiliation(s)
- Mitchell W. Alton
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
| | - Eleanor C. Browne
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
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7
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Whelan MJ, Kim J. Application of multimedia models for understanding the environmental behavior of volatile methylsiloxanes: Fate, transport, and bioaccumulation. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2022; 18:599-621. [PMID: 34375022 PMCID: PMC9293016 DOI: 10.1002/ieam.4507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/11/2021] [Accepted: 07/26/2021] [Indexed: 06/13/2023]
Abstract
Multimedia fate and transport models (MFTMs) describe how chemicals behave in the environment based on their inherent properties and the characteristics of receiving systems. We critically review the use of MFTMs for understanding the behavior of volatile methylsiloxanes (VMS). MFTMs have been used to predict the fate of VMS in wastewater treatment, rivers, lakes, marine systems, and the atmosphere, and to assess bioaccumulation and trophic transfers. More widely, they have been used to assess the overall persistence, long-range transport potential (LRTP), and the propensity for atmosphere-surface exchange. The application of MFTMs for VMS requires particularly careful selection of model inputs because the properties of VMS differ from those of most organic compounds. For example, although n-octanol/water partition coefficient (KOW ) values are high, air:water partition coefficient (KAW ) values are also high and n-octanol/air partition coefficient (KOA ) values are relatively low. In addition, organic carbon/water partition coefficient (KOC ) values are substantially lower than expectations based on KOW . This means that most empirical relationships between KOC and KOW are not appropriate. Good agreement between modeled and measured concentrations in air, sediment, and biota indicates that our understanding of environmental fate is reasonable. VMS compounds are "fliers" that principally partition to the atmosphere, implying high LRTP, although they have low redeposition potential. They are degraded in air (half-lives 3-10 days) and, thus, have low overall persistence. In water, exposure can be limited by hydrolysis, volatilization, and partitioning to sediments (where degradation half-lives are likely to be high). In food webs, they are influenced by metabolism in biota, which tends to drive trophic dilution (i.e., trophic magnification factors are often but not always <1). Key remaining uncertainties include the following: (i) the strength and direction of the temperature dependence for KOC ; (ii) the fate of atmospheric reaction products; and (iii) the magnitude of emissions to wastewater. Integr Environ Assess Manag 2022;18:599-621. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Affiliation(s)
- Michael J. Whelan
- Centre for Landscape and Climate Research, School of Geography, Geology and the EnvironmentUniversity of LeicesterLeicesterUK
| | - Jaeshin Kim
- Toxicology and Environmental Research and ConsultingThe Dow Chemical CompanyMidlandMichiganUSA
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8
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Xu J, Harrison RM, Song C, Hou S, Wei L, Fu P, Li H, Li W, Shi Z. PM 2.5-bound silicon-containing secondary organic aerosols (Si-SOA) in Beijing ambient air. CHEMOSPHERE 2022; 288:132377. [PMID: 34600012 DOI: 10.1016/j.chemosphere.2021.132377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 09/15/2021] [Accepted: 09/25/2021] [Indexed: 06/13/2023]
Abstract
Volatile methyl siloxanes (VMS) have been widely used in personal care products and industrial applications, and are an important component of VOCs (volatile organic compounds) indoors. They have sufficiently long lifetimes to undergo long-range transport and to form secondary aerosols through atmospheric oxidation. To investigate these silicon-containing secondary organic aerosols (Si-SOA), we collected PM2.5 samples during 8th-21st August 2018 (summer) and 3rd-23rd January 2019 (winter) at an urban site of Beijing. As the oxidation of VMS mainly results in hydrophilic polar semi-volatile and non-volatile oxidation products, the differences between total water-soluble Si and total water-soluble inorganic Si were used to estimate water-soluble organic Si, considered to be secondary organic Si (SO-Si). The average concentrations of SO-Si during the summer and winter campaigns were 4.6 ± 3.7 and 13.2 ± 8.6 ng m-3, accounting for approximately 80.1 ± 10.1% and 80.2 ± 8.7% of the total water-soluble Si, and 1.2 ± 1.2% and 5.0 ± 6.9% of total Si in PM2.5, respectively. The estimated Si-SOA concentrations were 12.7 ± 10.2 ng m-3 and 36.6 ± 23.9 ng m-3 on average in summer and winter, which accounted for 0.06 ± 0.07% and 0.16 ± 0.22% of PM2.5 mass, but increased to 0.26% and 0.92% on certain days. We found that net solar radiation is positively correlated with SO-Si levels in the summer but not in winter, suggesting seasonally different formation mechanisms.
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Affiliation(s)
- Jingsha Xu
- School of Geography Earth and Environmental Science, University of Birmingham, Birmingham, B15 2TT, UK; Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
| | - Roy M Harrison
- School of Geography Earth and Environmental Science, University of Birmingham, Birmingham, B15 2TT, UK; Department of Environmental Sciences/Center of Excellence in Environmental Studies, King Abdulaziz University, P.O. Box 80203, Jeddah, 21589, Saudi Arabia
| | - Congbo Song
- School of Geography Earth and Environmental Science, University of Birmingham, Birmingham, B15 2TT, UK
| | - Siqi Hou
- School of Geography Earth and Environmental Science, University of Birmingham, Birmingham, B15 2TT, UK
| | - Lianfang Wei
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Pingqing Fu
- Institute of Surface-Earth System Science, Tianjin University, Tianjin, 300072, China
| | - Hong Li
- Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Weijun Li
- Department of Earth and Atmospheric Sciences, Zhejiang University, Hangzhou, 310027, China
| | - Zongbo Shi
- School of Geography Earth and Environmental Science, University of Birmingham, Birmingham, B15 2TT, UK.
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9
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Pennington EA, Seltzer KM, Murphy BN, Qin M, Seinfeld JH, Pye HO. Modeling secondary organic aerosol formation from volatile chemical products. ATMOSPHERIC CHEMISTRY AND PHYSICS 2021; 21:18247-18261. [PMID: 35087576 PMCID: PMC8788583 DOI: 10.5194/acp-21-18247-2021] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Volatile chemical products (VCPs) are commonly-used consumer and industrial items that are an important source of anthropogenic emissions. Organic compounds from VCPs evaporate on atmospherically relevant time scales and include many species that are secondary organic aerosol (SOA) precursors. However, the chemistry leading to SOA, particularly that of intermediate volatility organic compounds (IVOCs), has not been fully represented in regional-scale models such as the Community Multiscale Air Quality (CMAQ) model, which tend to underpredict SOA concentrations in urban areas. Here we develop a model to represent SOA formation from VCP emissions. The model incorporates a new VCP emissions inventory and employs three new classes of emissions: siloxanes, oxygenated IVOCs, and nonoxygenated IVOCs. VCPs are estimated to produce 1.67 μg m-3 of noontime SOA, doubling the current model predictions and reducing the SOA mass concentration bias from -75% to -58% when compared to observations in Los Angeles in 2010. While oxygenated and nonoxygenated intermediate volatility VCP species are emitted in similar quantities, SOA formation is dominated by the nonoxygenated IVOCs. Formaldehyde and SOA show similar relationships to temperature and bias signatures indicating common sources and/or chemistry. This work suggests that VCPs contribute up to half of anthropogenic SOA in Los Angeles and models must better represent SOA precursors from VCPs to predict the urban enhancement of SOA.
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Affiliation(s)
- Elyse A. Pennington
- Oak Ridge Institute for Science and Education Fellow in the Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711
- Department of Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Karl M. Seltzer
- Oak Ridge Institute for Science and Education Fellow in the Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711
| | - Benjamin N. Murphy
- Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711
| | - Momei Qin
- Oak Ridge Institute for Science and Education Fellow in the Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, China
| | - John H. Seinfeld
- Department of Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Havala O.T. Pye
- Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711
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10
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Ma F, Xie HB, Li M, Wang S, Zhang R, Chen J. Autoxidation mechanism for atmospheric oxidation of tertiary amines: Implications for secondary organic aerosol formation. CHEMOSPHERE 2021; 273:129207. [PMID: 33349467 DOI: 10.1016/j.chemosphere.2020.129207] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/30/2020] [Accepted: 12/03/2020] [Indexed: 06/12/2023]
Abstract
Tertiary amines are one kind of identified amines in the atmosphere. Here, the atmospheric oxidation mechanism and kinetics of tertiary amines were investigated by using computational methods. As proxies of these amines, trimethylamine (TMA) and triethylamine (TEA) have been selected. Results indicate that N-containing peroxy radicals (NRO2⋅), which are key intermediates in ⋅OH initiated oxidation of TMA and TEA, can follow a so-called autoxidation mechanism (a chain reaction of H-shift followed by O2 addition) even on the condition of high NO/HO2⋅ concentration. Such unique mechanism can be ascribed to the ability of N-atom in facilitating the unimolecular H-shift of NRO2⋅ and the absence of H-atoms on N-atom. However, different from TMA reaction system, the pathway dissociating into fragmental products can compete with the autoxidation pathway for TEA system. More importantly, TEA reaction system cannot lead to the formation of products with high O/C ratio due to the autoxidation pathway terminated by the release of fragmental molecules. Such difference can be corroborated by previously observing lower secondary organic aerosol yield of TEA oxidation than that of TMA oxidation. The unveiled mechanism enhances current understanding on atmospheric fate of amines and autoxidation mechanism.
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Affiliation(s)
- Fangfang Ma
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China; Department of Atmospheric Sciences, Texas A&M University, College Station, TX, 77843, United States
| | - Hong-Bin Xie
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
| | - Mingxue Li
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China
| | - Sainan Wang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
| | - Renyi Zhang
- Department of Atmospheric Sciences, Texas A&M University, College Station, TX, 77843, United States
| | - Jingwen Chen
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024, China.
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11
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Seltzer KM, Pennington E, Rao V, Murphy BN, Strum M, Isaacs KK, Pye HOT. Reactive organic carbon emissions from volatile chemical products. ATMOSPHERIC CHEMISTRY AND PHYSICS 2021; 21:5079-5100. [PMID: 34122530 PMCID: PMC8193795 DOI: 10.5194/acp-21-5079-2021] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Volatile chemical products (VCPs) are an increasingly important source of anthropogenic reactive organic carbon (ROC) emissions. Among these sources are everyday items, such as personal care products, general cleaners, architectural coatings, pesticides, adhesives, and printing inks. Here, we develop VCPy, a new framework to model organic emissions from VCPs throughout the United States, including spatial allocation to regional and local scales. Evaporation of a species from a VCP mixture in the VCPy framework is a function of the compound-specific physiochemical properties that govern volatilization and the timescale relevant for product evaporation. We introduce two terms to describe these processes: evaporation timescale and use timescale. Using this framework, predicted national per capita organic emissions from VCPs are 9.5 kg per person per year (6.4 kg C per person per year) for 2016, which translates to 3.05 Tg (2.06 Tg C), making VCPs a dominant source of anthropogenic organic emissions in the United States. Uncertainty associated with this framework and sensitivity to select parameters were characterized through Monte Carlo analysis, resulting in a 95 % confidence interval of national VCP emissions for 2016 of 2.61-3.53 Tg (1.76-2.38 Tg C). This nationwide total is broadly consistent with the U.S. EPA's 2017 National Emission Inventory (NEI); however, county-level and categorical estimates can differ substantially from NEI values. VCPy predicts higher VCP emissions than the NEI for approximately half of all counties, with 5 % of all counties having greater than 55 % higher emissions. Categorically, application of the VCPy framework yields higher emissions for personal care products (150 %) and paints and coatings (25 %) when compared to the NEI, whereas pesticides (-54 %) and printing inks (-13 %) feature lower emissions. An observational evaluation indicates emissions of key species from VCPs are reproduced with high fidelity using the VCPy framework (normalized mean bias of -13 % with r =0.95). Sector-wide, the effective secondary organic aerosol yield and maximum incremental reactivity of VCPs are 5.3 % by mass and 1.58 gO3 g-1, respectively, indicating VCPs are an important, and likely to date underrepresented, source of secondary pollution in urban environments.
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Affiliation(s)
- Karl M Seltzer
- Oak Ridge Institute for Science and Education Postdoctoral Fellow in the Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Elyse Pennington
- Oak Ridge Institute for Science and Education Fellow in the Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
- California Institute of Technology, Pasadena, CA 91125, USA
| | - Venkatesh Rao
- Office of Air and Radiation, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Benjamin N Murphy
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Madeleine Strum
- Office of Air and Radiation, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Kristin K Isaacs
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Havala O T Pye
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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12
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Horii Y, Ohtsuka N, Minomo K, Takemine S, Motegi M, Hara M. Distribution characteristics of methylsiloxanes in atmospheric environment of Saitama, Japan: Diurnal and seasonal variations and emission source apportionment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 754:142399. [PMID: 33254939 DOI: 10.1016/j.scitotenv.2020.142399] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/27/2020] [Accepted: 09/13/2020] [Indexed: 06/12/2023]
Abstract
The large production volume of methylsiloxanes (MSs), combined with their high mobility/volatility and persistence, is a matter of concern from the atmospheric pollution perspective. Therefore, we evaluated of the concentrations and emission sources of MSs, including 7 cyclic methylsiloxanes (D3-D9; CMSs, the number refers to the number of Si-O bonds) and 13 linear methylsiloxanes (L3-L15; LMSs) in ambient air collected from Saitama, Japan. This is a first study regarding the evaluation of 20 methylsiloxanes in the Japanese atmosphere. We improved the air sampling methodology by determination the stability of D5 during a 7-d air sampling and arbitrary sample storage period using polystyrene-divinyl benzene copolymer sorbent (Sep-Pak plus PS-2). We analyzed air samples for MSs seasonally collected from nine locations in Saitama, including urban, suburban, rural, and mountainous areas. The mean CMS and LMS concentrations were 358 ng m-3 and 13.4 ng m-3, respectively. The D5 concentrations were distributed widely, with high concentrations in urban/suburban populous areas and dispersed at low concentrations in surrounding areas (north and mountainous areas). We analyzed 7-d air samples collected every week over a year and found apparent seasonal and periodic trends in the CMS concentrations. In the diurnal sampling campaign, we observed periodic fluctuations in ambient CMSs, with an inverse relationship with the atmospheric boundary layer development during the day. Backward trajectories and the prevailing wind direction during the sampling period indicated that the specific profiles of D4 observed in fall/winter weeks and north of Saitama could be ascribed to northwestward air-mass advection. We employed a novel approach in estimating CMSs emission sources and source apportionment by using non-negative matrix factorization (NMF). The concentration matrix was divided successfully into two factors (emission sources) namely, personal care and household products and industrial activities.
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Affiliation(s)
- Yuichi Horii
- Center for Environmental Science in Saitama, 914 Kamitanadare, Kazo, Saitama 347-0115, Japan.
| | - Nobutoshi Ohtsuka
- Center for Environmental Science in Saitama, 914 Kamitanadare, Kazo, Saitama 347-0115, Japan
| | - Kotaro Minomo
- Center for Environmental Science in Saitama, 914 Kamitanadare, Kazo, Saitama 347-0115, Japan
| | - Shusuke Takemine
- Center for Environmental Science in Saitama, 914 Kamitanadare, Kazo, Saitama 347-0115, Japan
| | - Mamoru Motegi
- Center for Environmental Science in Saitama, 914 Kamitanadare, Kazo, Saitama 347-0115, Japan
| | - Masayuki Hara
- Center for Environmental Science in Saitama, 914 Kamitanadare, Kazo, Saitama 347-0115, Japan
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13
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Gkatzelis GI, Coggon MM, McDonald BC, Peischl J, Aikin KC, Gilman JB, Trainer M, Warneke C. Identifying Volatile Chemical Product Tracer Compounds in U.S. Cities. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:188-199. [PMID: 33325693 DOI: 10.1021/acs.est.0c05467] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
With traffic emissions of volatile organic compounds (VOCs) decreasing rapidly over the last decades, the contributions of the emissions from other source categories, such as volatile chemical products (VCPs), have become more apparent in urban air. In this work, in situ measurements of various VOCs are reported for New York City, Pittsburgh, Chicago, and Denver. The magnitude of different emission sources relative to traffic is determined by measuring the urban enhancement of individual compounds relative to the enhancement of benzene, a known tracer of fossil fuel in the United States. The enhancement ratios of several VCP compounds to benzene correlate well with population density (R2 ∼ 0.6-0.8). These observations are consistent with the expectation that some human activity should correlate better with the population density than transportation emissions, due to the lower per capita rate of driving in denser cities. Using these data, together with a bottom-up fuel-based inventory of vehicle emissions and volatile chemical products (FIVE-VCP) inventory, we identify tracer compounds for different VCP categories: decamethylcyclopentasiloxane (D5-siloxane) for personal care products, monoterpenes for fragrances, p-dichlorobenzene for insecticides, D4-siloxane for adhesives, para-chlorobenzotrifluoride (PCBTF) for solvent-based coatings, and Texanol for water-based coatings. Furthermore, several other compounds are identified (e.g., ethanol) that correlate with population density and originate from multiple VCP sources. Ethanol and fragrances are among the most abundant and reactive VOCs associated with VCP emissions.
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Affiliation(s)
- Georgios I Gkatzelis
- NOAA Chemical Sciences Laboratory, Earth System Research Laboratories, 325 Broadway, R/CSL7, Boulder, Colorado 80305, United States
- Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado 80309, United States
| | - Matthew M Coggon
- NOAA Chemical Sciences Laboratory, Earth System Research Laboratories, 325 Broadway, R/CSL7, Boulder, Colorado 80305, United States
- Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado 80309, United States
| | - Brian C McDonald
- NOAA Chemical Sciences Laboratory, Earth System Research Laboratories, 325 Broadway, R/CSL7, Boulder, Colorado 80305, United States
| | - Jeff Peischl
- NOAA Chemical Sciences Laboratory, Earth System Research Laboratories, 325 Broadway, R/CSL7, Boulder, Colorado 80305, United States
- Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado 80309, United States
| | - Kenneth C Aikin
- NOAA Chemical Sciences Laboratory, Earth System Research Laboratories, 325 Broadway, R/CSL7, Boulder, Colorado 80305, United States
- Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado 80309, United States
| | - Jessica B Gilman
- NOAA Chemical Sciences Laboratory, Earth System Research Laboratories, 325 Broadway, R/CSL7, Boulder, Colorado 80305, United States
| | - Michael Trainer
- NOAA Chemical Sciences Laboratory, Earth System Research Laboratories, 325 Broadway, R/CSL7, Boulder, Colorado 80305, United States
| | - Carsten Warneke
- NOAA Chemical Sciences Laboratory, Earth System Research Laboratories, 325 Broadway, R/CSL7, Boulder, Colorado 80305, United States
- Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado 80309, United States
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14
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Qin M, Murphy BN, Isaacs KK, McDonald BC, Lu Q, McKeen SA, Koval L, Robinson AL, Efstathiou C, Allen C, Pye HO. Criteria pollutant impacts of volatile chemical products informed by near-field modeling. NATURE SUSTAINABILITY 2020; N/A:1-57. [PMID: 33134558 PMCID: PMC7592713 DOI: 10.1038/s41893-020-00614-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 08/26/2020] [Indexed: 05/20/2023]
Abstract
Consumer, industrial, and commercial product usage is a source of exposure to potentially hazardous chemicals. In addition, cleaning agents, personal care products, coatings, and other volatile chemical products (VCPs), evaporate and react in the atmosphere producing secondary pollutants. Here, we show high air emissions from VCP usage (≥ 14 kg person-1 yr-1, at least 1.7× higher than current operational estimates) are supported by multiple estimation methods and constraints imposed by ambient levels of ozone, hydroxyl radical (OH) reactivity, and the organic component of fine particulate matter (PM2.5) in Pasadena, California. A near-field model, which estimates human chemical exposure during or in the vicinity of product use, indicates these high air emissions are consistent with organic product usage up to ~75 kg person-1 yr-1, and inhalation of consumer products could be a non-negligible exposure pathway. After constraining the PM2.5 yield to 5% by mass, VCPs produce ~41% of the photochemical organic PM2.5 (1.1 ± 0.3 μg m-3) and ~17% of maximum daily 8-hr average ozone (9 ± 2 ppb) in summer Los Angeles. Therefore, both toxicity and ambient criteria pollutant formation should be considered when organic substituents are developed for VCPs in pursuit of safer and sustainable products and cleaner air.
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Affiliation(s)
- Momei Qin
- Oak Ridge Institute for Science and Education (ORISE) Research Participant at the Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, China
- Correspondence to: Momei Qin () and Havala Pye ()
| | - Benjamin N. Murphy
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
| | - Kristin K. Isaacs
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
| | - Brian C. McDonald
- Chemical Sciences Laboratory, NOAA Earth System Research Laboratories, Boulder, Colorado, USA
| | - Quanyang Lu
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
- Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Stuart A. McKeen
- Chemical Sciences Laboratory, NOAA Earth System Research Laboratories, Boulder, Colorado, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA
| | - Lauren Koval
- Oak Ridge Institute for Science and Education (ORISE) Research Participant at the Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
| | - Allen L. Robinson
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
- Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Christos Efstathiou
- General Dynamics Information Technology Research Triangle Park, North Carolina, USA
| | - Chris Allen
- General Dynamics Information Technology Research Triangle Park, North Carolina, USA
| | - Havala O.T. Pye
- Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
- Correspondence to: Momei Qin () and Havala Pye ()
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15
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Ren Z, da Silva G. Auto-Oxidation of a Volatile Silicon Compound: A Theoretical Study of the Atmospheric Chemistry of Tetramethylsilane. J Phys Chem A 2020; 124:6544-6551. [DOI: 10.1021/acs.jpca.0c02922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhonghua Ren
- Department of Chemical Engineering, The University of Melbourne, Parkville 3010, Australia
| | - Gabriel da Silva
- Department of Chemical Engineering, The University of Melbourne, Parkville 3010, Australia
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16
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Fu Z, Xie HB, Elm J, Guo X, Fu Z, Chen J. Formation of Low-Volatile Products and Unexpected High Formaldehyde Yield from the Atmospheric Oxidation of Methylsiloxanes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:7136-7145. [PMID: 32401014 DOI: 10.1021/acs.est.0c01090] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
With stricter regulation of atmospheric volatile organic compounds (VOCs) originating from fossil fuel-based vehicles and industries, the use of volatile chemical products (VCPs) and the transformation mechanism of VCPs have become increasingly important to quantify air quality. Volatile methylsiloxanes (VMS) are an important class of VCPs and high-production chemicals. Using quantum chemical calculations and kinetics modeling, we investigated the reaction mechanism of peroxy radicals of VMS, which are key intermediates in determining the atmospheric chemistry of VMS. L2-RSiCH2O2• and D3-RSiCH2O2• derived from hexamethyldisiloxane and hexamethylcyclotrisiloxane, respectively, were selected as representative model systems. The results indicated that L2-RSiCH2O2• and D3-RSiCH2O2• follow a novel Si-C-O rearrangement-driven autoxidation mechanism, leading to the formation of low volatile silanols and high yield of formaldehyde at low NO/HO2• conditions. At high NO/HO2• conditions, L2-RSiCH2O2• and D3-RSiCH2O2• react with NO/HO2• to form organic nitrate, hydroperoxide, and active alkoxy radicals. The alkoxy radicals further follow a Si-C-O rearrangement step to finally form formate esters. The novel Si-C-O rearrangement mechanism of both peroxy and alkoxy radicals are supported by available experimental studies on the oxidation of VMS. Notably, the high yield of formaldehyde is estimated to significantly contribute to formaldehyde pollution in the indoor environment, especially during indoor cleaning.
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Affiliation(s)
- Zihao Fu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Hong-Bin Xie
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Jonas Elm
- Department of Chemistry and iClimate, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Xirui Guo
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Zhiqiang Fu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta T6G2R3, Canada
| | - Jingwen Chen
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
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17
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Alton MW, Browne EC. Atmospheric Chemistry of Volatile Methyl Siloxanes: Kinetics and Products of Oxidation by OH Radicals and Cl Atoms. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:5992-5999. [PMID: 32339458 DOI: 10.1021/acs.est.0c01368] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Volatile methyl siloxanes (VMS) are ubiquitous anthropogenic pollutants that have recently come under scrutiny for their potential toxicity and environmental persistence. In this work, we determined the rate constants for oxidation by OH radicals and Cl atoms at 297 ± 3 K and atmospheric pressure in Boulder, CO (∼860 mbar) of hexamethyldisiloxane (L2), octamethyltrisiloxane (L3), decamethyltetrasiloxane (L4), dodecamethylpentasiloxane (L5), hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). Measured rate constants with OH radicals were (1.20 ± 0.09) × 10-12, (1.7 ± 0.1) × 10-12, (2.5 ± 0.2) × 10-12, (3.4 ± 0.5) × 10-12, (0.86 ± 0.09) × 10-12, (1.3 ± 0.1) × 10-12, and (2.1 ± 0.1) × 10-12 cm3 molec-1 s-1, for L2, L3, L4, L5, D3, D4, and D5, respectively. The rate constants for reactions with Cl atoms with the same compounds were (1.44 ± 0.05) × 10-10, (1.85 ± 0.05) × 10-10, (2.2 ± 0.1) × 10-10, (2.9 ± 0.1) × 10-10, (0.56 ± 0.05) × 10-10, (1.16 ± 0.08) × 10-10, and (1.8 ± 0.1) × 10-10 cm3 molec-1 s-1, respectively. Substituent factors of F(-Si(CH3)2OR) and F(-SiCH3(OR)2) are proposed for use in AOPWIN, a common model for OH radical rate constant estimations. Cl atoms can remove percentage levels of VMS globally with potentially increased importance in urban areas.
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Affiliation(s)
- Mitchell W Alton
- Department of Chemistry and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
| | - Eleanor C Browne
- Department of Chemistry and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
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18
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King BM, Janechek NJ, Bryngelson N, Adamcakova-Dodd A, Lersch T, Bunker K, Casuccio G, Thorne PS, Stanier CO, Fiegel J. Lung cell exposure to secondary photochemical aerosols generated from OH oxidation of cyclic siloxanes. CHEMOSPHERE 2020; 241:125126. [PMID: 31683444 PMCID: PMC6941482 DOI: 10.1016/j.chemosphere.2019.125126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 10/13/2019] [Accepted: 10/14/2019] [Indexed: 06/10/2023]
Abstract
To study the fate of cyclic volatile methyl siloxanes (cVMS) undergoing photooxidation in the environment and to assess the acute toxicity of inhaled secondary aerosols from cVMS, we used an oxidative flow reactor (OFR) to produce aerosols from oxidation of decamethylcyclopentasiloxane (D5). The aerosols produced from this process were characterized for size, shape, and chemical composition. We found that the OFR produced aerosols composed of silicon and oxygen, arranged in chain agglomerates, with primary particles of approximately 31 nm in diameter. Lung cells were exposed to the secondary organosilicon aerosols at estimated doses of 54-116 ng/cm2 using a Vitrocell air-liquid interface system, and organic gases and ozone exposure was minimized through a series of denuders. Siloxane aerosols were not found to be highly toxic.
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Affiliation(s)
- Benjamin M King
- Department of Chemical and Biochemical Engineering, The University of Iowa, 4133 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA
| | - Nathan J Janechek
- Department of Chemical and Biochemical Engineering, The University of Iowa, 4133 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA
| | - Nathan Bryngelson
- Department of Chemical and Biochemical Engineering, The University of Iowa, 4133 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA
| | - Andrea Adamcakova-Dodd
- Department of Occupational and Environmental Health, The University of Iowa, 145 N. Riverside Dr., Iowa City, IA, 52242, USA
| | - Traci Lersch
- RJ Lee Group, 350 Hochberg Road, Monroeville, PA, 15146, USA
| | - Kristin Bunker
- RJ Lee Group, 350 Hochberg Road, Monroeville, PA, 15146, USA
| | - Gary Casuccio
- RJ Lee Group, 350 Hochberg Road, Monroeville, PA, 15146, USA
| | - Peter S Thorne
- Department of Occupational and Environmental Health, The University of Iowa, 145 N. Riverside Dr., Iowa City, IA, 52242, USA
| | - Charles O Stanier
- Department of Chemical and Biochemical Engineering, The University of Iowa, 4133 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA.
| | - Jennifer Fiegel
- Department of Chemical and Biochemical Engineering, The University of Iowa, 4133 Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, 52242, USA.
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19
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Shah RU, Coggon MM, Gkatzelis GI, McDonald BC, Tasoglou A, Huber H, Gilman J, Warneke C, Robinson AL, Presto AA. Urban Oxidation Flow Reactor Measurements Reveal Significant Secondary Organic Aerosol Contributions from Volatile Emissions of Emerging Importance. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:714-725. [PMID: 31851821 DOI: 10.1021/acs.est.9b06531] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Mobile sampling studies have revealed enhanced levels of secondary organic aerosol (SOA) in source-rich urban environments. While these enhancements can be from rapidly reacting vehicular emissions, it was recently hypothesized that nontraditional emissions (volatile chemical products and upstream emissions) are emerging as important sources of urban SOA. We tested this hypothesis by using gas and aerosol mass spectrometry coupled with an oxidation flow reactor (OFR) to characterize pollution levels and SOA potentials in environments influenced by traditional emissions (vehicular, biogenic), and nontraditional emissions (e.g., paint fumes). We used two SOA models to assess contributions of vehicular and biogenic emissions to our observed SOA. The largest gap between observed and modeled SOA potential occurs in the morning-time urban street canyon environment, for which our model can only explain half of our observation. Contributions from VCP emissions (e.g., personal care products) are highest in this environment, suggesting that VCPs are an important missing source of precursors that would close the gap between modeled and observed SOA potential. Targeted OFR oxidation of nontraditional emissions shows that these emissions have SOA potentials that are similar, if not larger, compared to vehicular emissions. Laboratory experiments reveal large differences in SOA potentials of VCPs, implying the need for further characterization of these nontraditional emissions.
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Affiliation(s)
- Rishabh U Shah
- Center for Atmospheric Particle Studies , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
- Mechanical Engineering , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Matthew M Coggon
- Chemical Sciences Division , National Oceanic and Atmospheric Administration, Earth Systems Research Laboratory , Boulder , Colorado 80305 , United States
- Cooperative Institute for Research in Environmental Sciences , University of Colorado , Boulder , Colorado 80309 , United States
| | - Georgios I Gkatzelis
- Chemical Sciences Division , National Oceanic and Atmospheric Administration, Earth Systems Research Laboratory , Boulder , Colorado 80305 , United States
- Cooperative Institute for Research in Environmental Sciences , University of Colorado , Boulder , Colorado 80309 , United States
| | - Brian C McDonald
- Chemical Sciences Division , National Oceanic and Atmospheric Administration, Earth Systems Research Laboratory , Boulder , Colorado 80305 , United States
- Cooperative Institute for Research in Environmental Sciences , University of Colorado , Boulder , Colorado 80309 , United States
| | - Antonios Tasoglou
- R. J. Lee Group Inc. , Monroeville , Pennsylvania 15146 , United States
| | - Heinz Huber
- R. J. Lee Group Inc. , Monroeville , Pennsylvania 15146 , United States
| | - Jessica Gilman
- Chemical Sciences Division , National Oceanic and Atmospheric Administration, Earth Systems Research Laboratory , Boulder , Colorado 80305 , United States
| | - Carsten Warneke
- Chemical Sciences Division , National Oceanic and Atmospheric Administration, Earth Systems Research Laboratory , Boulder , Colorado 80305 , United States
- Cooperative Institute for Research in Environmental Sciences , University of Colorado , Boulder , Colorado 80309 , United States
| | - Allen L Robinson
- Center for Atmospheric Particle Studies , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
- Mechanical Engineering , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Albert A Presto
- Center for Atmospheric Particle Studies , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
- Mechanical Engineering , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
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20
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Peng Z, Jimenez JL. Radical chemistry in oxidation flow reactors for atmospheric chemistry research. Chem Soc Rev 2020; 49:2570-2616. [DOI: 10.1039/c9cs00766k] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We summarize the studies on the chemistry in oxidation flow reactor and discuss its atmospheric relevance.
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Affiliation(s)
- Zhe Peng
- Cooperative Institute for Research in Environmental Sciences and Department of Chemistry
- University of Colorado
- Boulder
- USA
| | - Jose L. Jimenez
- Cooperative Institute for Research in Environmental Sciences and Department of Chemistry
- University of Colorado
- Boulder
- USA
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21
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Tran TM, Hoang AQ, Le ST, Minh TB, Kannan K. A review of contamination status, emission sources, and human exposure to volatile methyl siloxanes (VMSs) in indoor environments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 691:584-594. [PMID: 31325858 DOI: 10.1016/j.scitotenv.2019.07.168] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/08/2019] [Accepted: 07/11/2019] [Indexed: 06/10/2023]
Abstract
Siloxanes are organo-silicon compounds containing Si-O-Si linkages and methyl branches. Depending on the structure, siloxanes can be divided into cyclic and linear compounds. Methyl siloxanes with small and medium molecular weights (molecular weights less than 500 g mol-1), are volatile under normal conditions, and hence are referred to as volatile methyl siloxanes (VMSs). VMSs are additive ingredients in many products such as plastics, rubber, personal care products, and household items. This review provides information on the distribution of VMSs in consumer products, indoor air and dust, and their implications for human exposure. VMSs have been used in personal care products and household items at concentrations on the order of hundreds to thousands of micrograms per gram which are the main sources of contamination in the indoor environments. VMSs have been found widely in indoor air and dust. A significant correlation existed between VMS concentrations in indoor air and dust. Among typical VMSs, dodecamethylcylcopentasiloxane (D5) is the major compound found in indoor environments. The human exposure doses to VMSs through dermal absorption, dust ingestion, and inhalation were compiled; Inhalation is a dominant pathway of exposure to VMSs, especially in indoor environments of occupational settings like hair salons. The human exposure doses were higher in children than in adults.
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Affiliation(s)
- Tri Manh Tran
- Faculty of Chemistry, VNU University of Science, Vietnam National University, 19 Le Thanh Tong, Hanoi, Viet Nam.
| | - Anh Quoc Hoang
- Faculty of Chemistry, VNU University of Science, Vietnam National University, 19 Le Thanh Tong, Hanoi, Viet Nam; Center of Advanced Technology for the Environment (CATE), Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama 790-8566, Japan; The United Graduate School of Agricultural Sciences (UGAS-EU), Ehime University, 3-5-7 Tarumi, Matsuyama 790-8566, Japan
| | - Son Thanh Le
- Faculty of Chemistry, VNU University of Science, Vietnam National University, 19 Le Thanh Tong, Hanoi, Viet Nam
| | - Tu Binh Minh
- Faculty of Chemistry, VNU University of Science, Vietnam National University, 19 Le Thanh Tong, Hanoi, Viet Nam
| | - Kurunthachalam Kannan
- Wadsworth Center, New York State Department of Health, and Department of Environmental Health Sciences, School of Public Health, State University of New York at Albany, Empire State Plaza, P.O. Box 509, Albany, NY 12201-0509, United States; Biochemistry Department, Faculty of Science and Experimental Biochemistry Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
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