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Wang N, Jiang F, Xu L, Cai Y. Profiles, exposure assessment and expanded screening of PAHs and their derivatives in one petroleum refinery facility of China. J Environ Sci (China) 2025; 147:550-560. [PMID: 39003070 DOI: 10.1016/j.jes.2023.09.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/13/2023] [Accepted: 09/29/2023] [Indexed: 07/15/2024]
Abstract
This study investigated environmental distribution and human exposure of polycyclic aromatic hydrocarbons (PAHs) and their derivatives in one Chinese petroleum refinery facility. It was found that, following with high concentrations of 16 EPA PAHs (∑Parent-PAHs) in smelting subarea of studied petroleum refinery facility, total derivatives of PAHs [named as XPAHs, including nitro PAHs (NPAHs), chlorinated PAHs (Cl-PAHs), and brominated PAHs (Br-PAHs)] in gas (mean= 1.57 × 104 ng/m3), total suspended particulate (TSP) (mean= 4.33 × 103 ng/m3) and soil (mean= 4.37 × 103 ng/g) in this subarea had 1.76-6.19 times higher levels than those from other subareas of this facility, surrounding residential areas and reference areas, indicating that petroleum refining processes would lead apparent derivation of PAHs. Especially, compared with those in residential and reference areas, gas samples in the petrochemical areas had higher ∑NPAH/∑PAHs (mean=2.18), but lower ∑Cl-PAH/∑PAHs (mean=1.43 × 10-1) and ∑Br-PAH/∑PAHs ratios (mean=7.49 × 10-2), indicating the richer nitrification of PAHs than chlorination during petrochemical process. The occupational exposure to PAHs and XPAHs in this petroleum refinery facility were 24-343 times higher than non-occupational exposure, and the ILCR (1.04 × 10-4) for petrochemical workers was considered to be potential high risk. Furthermore, one expanded high-resolution screening through GC Orbitrap/MS was performed for soils from petrochemical area, and another 35 PAHs were found, including alkyl-PAHs, phenyl-PAHs and other species, indicating that profiles and risks of PAHs analogs in petrochemical areas deserve further expanded investigation.
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Affiliation(s)
- Ning Wang
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, China; Resource and Environmental Innovation Institute, Shandong Jianzhu University, Jinan 250101, China
| | - Fengjiao Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Lin Xu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Yaqi Cai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 330106, China; Hubei Key Laboratory of Environmental and Health Effects of Persistence Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China
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2
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Zhong S, Liu R, Yue S, Wang P, Zhang Q, Ma C, Deng J, Qi Y, Zhu J, Liu CQ, Kawamura K, Fu P. Peatland Wildfires Enhance Nitrogen-Containing Organic Compounds in Marine Aerosols over the Western Pacific. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:10991-11002. [PMID: 38829627 DOI: 10.1021/acs.est.3c10125] [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: 06/05/2024]
Abstract
Peatland wildfires contribute significantly to the atmospheric release of light-absorbing organic carbon, often referred to as brown carbon. In this study, we examine the presence of nitrogen-containing organic compounds (NOCs) within marine aerosols across the Western Pacific Ocean, which are influenced by peatland fires from Southeast Asia. Employing ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) in electrospray ionization (ESI) positive mode, we discovered that NOCs are predominantly composed of reduced nitrogenous bases, including CHN+ and CHON+ groups. Notably, the count of NOC formulas experiences a marked increase within plumes from peatland wildfires compared to those found in typical marine air masses. These NOCs, often identified as N-heterocyclic alkaloids, serve as potential light-absorbing chromophores. Furthermore, many NOCs demonstrate pyrolytic stability, engage in a variety of substitution reactions, and display enhanced hydrophilic properties, attributed to chemical processes such as methoxylation, hydroxylation, methylation, and hydrogenation that occur during emission and subsequent atmospheric aging. During the daytime atmospheric transport, aging of aromatic N-heterocyclic compounds, particularly in aliphatic amines prone to oxidation and reactions with amine, was observed. The findings underscore the critical role of peatland wildfires in augmenting nitrogen-containing organics in marine aerosols, underscoring the need for in-depth research into their effects on marine ecosystems and regional climatic conditions.
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Affiliation(s)
- Shujun Zhong
- Institute of Surface-Earth Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
- Scientific Research Academy of Guangxi Environment Protection, Nanning, Guangxi Zhuang Autonomous Region 530022, China
| | - Rui Liu
- Institute of Surface-Earth Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Siyao Yue
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Peng Wang
- Department of Atmospheric and Oceanic Sciences, Fudan University, Shanghai 200438, China
| | - Qiang Zhang
- Institute of Surface-Earth Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Chao Ma
- Institute of Surface-Earth Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Junjun Deng
- Institute of Surface-Earth Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Yulin Qi
- Institute of Surface-Earth Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Jialei Zhu
- Institute of Surface-Earth Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Cong-Qiang Liu
- Institute of Surface-Earth Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Kimitaka Kawamura
- Chubu Institute for Advanced Studies, Chubu University, Kasugai 487-8501, Japan
| | - Pingqing Fu
- Institute of Surface-Earth Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
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Mabato BG, Li YJ, Huang DD, Chan CK. Aqueous-Phase Photoreactions of Mixed Aromatic Carbonyl Photosensitizers Yield More Oxygenated, Oxidized, and less Light-Absorbing Secondary Organic Aerosol (SOA) than Single Systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:7924-7936. [PMID: 38652049 PMCID: PMC11080053 DOI: 10.1021/acs.est.3c10199] [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: 12/04/2023] [Revised: 03/27/2024] [Accepted: 03/28/2024] [Indexed: 04/25/2024]
Abstract
Aromatic carbonyls have been mainly probed as photosensitizers for aqueous secondary organic aerosol (aqSOA) and light-absorbing organic aerosol (i.e., brown carbon or BrC) formation, but due to their organic nature, they can also undergo oxidation to form aqSOA and BrC. However, photochemical transformations of aromatic carbonyl photosensitizers, particularly in multicomponent systems, are understudied. This study explored aqSOA formation from the irradiation of aromatic carbonyl photosensitizers in mixed and single systems under cloud/fog conditions. Mixed systems consisting of phenolic carbonyls only (VL + ActSyr + SyrAld: vanillin [VL] + acetosyringone [ActSyr] + syringaldehyde [SyrAld]) and another composed of both nonphenolic and phenolic carbonyls (DMB + ActSyr + SyrAld: 3,4-dimethoxybenzaldehyde [DMB], a nonphenolic carbonyl, + ActSyr + SyrAld) were compared to single systems of VL (VL*) and DMB (DMB*), respectively. In mixed systems, the shorter lifetimes of VL and DMB indicate their diminished capacity to trigger the oxidation of other organic compounds (e.g., guaiacol [GUA], a noncarbonyl phenol). In contrast to the slow decay and minimal photoenhancement for DMB*, the rapid photodegradation and significant photoenhancement for VL* indicate efficient direct photosensitized oxidation (i.e., self-photosensitization). Relative to single systems, the increased oxidant availability promoted functionalization in VL + ActSyr + SyrAld and accelerated the conversion of early generation aqSOA in DMB + ActSyr + SyrAld. Moreover, the increased availability of oxidizable substrates countered by stronger oxidative capacity limited the contribution of mixed systems to aqSOA light absorption. This suggests a weaker radiative effect of BrC from mixed photosensitizer systems than BrC from single photosensitizer systems. Furthermore, more oxygenated and oxidized aqSOA was observed with increasing complexity of the reaction systems (e.g., VL* < VL + ActSyr + SyrAld < VL + ActSyr + SyrAld + GUA). This work offers new insights into aqSOA formation by emphasizing the dual role of organic photosensitizers as oxidant sources and oxidizable substrates.
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Affiliation(s)
- Beatrix
Rosette Go Mabato
- School
of Energy and Environment, City University
of Hong Kong, Tat Chee Avenue, Kowloon 999077, Hong Kong SAR, China
| | - Yong Jie Li
- Department
of Civil and Environmental Engineering, and Centre for Regional Ocean,
Faculty of Science and Technology, University
of Macau, Macau 999078, China
| | - Dan Dan Huang
- Shanghai
Academy of Environmental Sciences, Shanghai 200233, China
| | - Chak K. Chan
- School
of Energy and Environment, City University
of Hong Kong, Tat Chee Avenue, Kowloon 999077, Hong Kong SAR, China
- Division
of Physical Sciences and Engineering, King
Abdullah University of Science and Technology (KAUST), Thuwal, Jeddah 23955-6900, Kingdom
of Saudi Arabia
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4
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Ahmed M, Rappenglueck B, Ganranoo L, Dasgupta PK. Source apportionment of gaseous Nitrophenols and their contribution to HONO formation in an urban area. CHEMOSPHERE 2023; 338:139499. [PMID: 37467859 DOI: 10.1016/j.chemosphere.2023.139499] [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: 04/10/2023] [Revised: 07/11/2023] [Accepted: 07/12/2023] [Indexed: 07/21/2023]
Abstract
Nitrophenols (NPs) have significant impacts on human health, climate, and atmospheric chemistry. Despite numerous measurements of particulate NPs, still little is known about their gaseous atmospheric abundances, sources, and fate. Here, four gaseous NPs [2,4-dinitrophenol (2,4-DNP), 4-nitrophenol (4-NP), 2-nitrophenol (2-NP), and 2-Methyl-4-nitrophenol (2-Me-4-NP)] were continuously monitored during late Spring at an urban site in Houston, Texas. Among the four NPs, 4-NP showed the highest abundance, followed by 2-Me-4-NP, 2-NP, and 2,4-DNP with average concentrations of 1.07 ± 0.19 ppt, 0.47 ± 0.12 ppt, 0.41 ± 0.16 ppt, and 0.27 ± 0.09 ppt, respectively. The positive matrix factorization (PMF) model identified seven sources: industrial NPs, secondary formation, phenol sources, acetonitrile source, natural gas/crude oil, traffic, and petrochemical industries/oil refineries. A zero-dimensional photochemical box model was used to simulate the observed 2-NP and 2,4-DNP. A 50.0% and 70.0% jNO2 was found to be consistent with the measured 2-NP and 2,4-DNP. This yields a nitrous acid (HONO) production of 7.5 ± 2.5 ppt/h from 06:00 to 18:00 Central Standard Time (CST) from both NPs. An extrapolation including other known NPs suggests a maximum HONO formation of 13.8 ppt/h. The results of this study suggest that using PMF analysis supplemented by photochemical box model provides identification of the NPs sources and their atmospheric implication to HONO formation.
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Affiliation(s)
- Morshad Ahmed
- Institute for Climate and Atmospheric Science, Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USA.
| | - Bernhard Rappenglueck
- Institute for Climate and Atmospheric Science, Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USA
| | - Lucksagoon Ganranoo
- Department of Chemistry, School of Science, University of Phayao, Phayao, Thailand
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Liu X, Wang H, Wang F, Lv S, Wu C, Zhao Y, Zhang S, Liu S, Xu X, Lei Y, Wang G. Secondary Formation of Atmospheric Brown Carbon in China Haze: Implication for an Enhancing Role of Ammonia. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:11163-11172. [PMID: 37406304 PMCID: PMC10399565 DOI: 10.1021/acs.est.3c03948] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/21/2023] [Accepted: 06/21/2023] [Indexed: 07/07/2023]
Abstract
Optical characteristics and molecular compositions of brown carbon (BrC) were investigated during winter 2019 at a rural site of China with a focus on nitro-aromatic compounds (NACs) and imidazoles (IMs). The abundance of gaseous nitrophenols relative to CO during the campaign maximized at noontime, being similar to O3, while the particulate NACs during the haze periods strongly correlated with toluene and NO2, suggesting that NACs in the region are largely formed from the gas-phase photooxidation. Strong correlations of particulate IMs in the dry haze periods with the mass ratio of EC/PM2.5 and the concentration of levoglucosan were observed, indicating that IMs during the dry events are largely derived from biomass burning emissions. However, an increase in IMs with the increasing aerosol liquid water content and pH was observed in the humid haze events, along with much lower abundances of levoglucosan and K+ relative to PM2.5, suggesting that IMs were mostly formed from aqueous reactions in the humid haze periods. These IMs exponentially increased with an increasing NH3 owing to an aqueous reaction of carbonyls with free ammonia. Our findings for the first time revealed an enhancing effect of ammonia on BrC formation in China, especially in humid haze periods.
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Affiliation(s)
- Xiaodi Liu
- Key
Laboratory of Geographic Information Science of the Ministry of Education,
School of Geographic Sciences, East China
Normal University, Shanghai 200241, China
| | - Haoyang Wang
- Laboratory
of Mass Spectrometry Analysis, Shanghai
Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Fanglin Wang
- Key
Laboratory of Geographic Information Science of the Ministry of Education,
School of Geographic Sciences, East China
Normal University, Shanghai 200241, China
| | - Shaojun Lv
- Key
Laboratory of Geographic Information Science of the Ministry of Education,
School of Geographic Sciences, East China
Normal University, Shanghai 200241, China
| | - Can Wu
- Key
Laboratory of Geographic Information Science of the Ministry of Education,
School of Geographic Sciences, East China
Normal University, Shanghai 200241, China
- Institute
of Eco-Chongming, Cuiniao
Road, Chenjia Zhen, Chongming, Shanghai 202150, China
| | - Yu Zhao
- Key
Laboratory of Geographic Information Science of the Ministry of Education,
School of Geographic Sciences, East China
Normal University, Shanghai 200241, China
| | - Si Zhang
- Key
Laboratory of Geographic Information Science of the Ministry of Education,
School of Geographic Sciences, East China
Normal University, Shanghai 200241, China
| | - Shijie Liu
- Key
Laboratory of Geographic Information Science of the Ministry of Education,
School of Geographic Sciences, East China
Normal University, Shanghai 200241, China
| | - Xinbei Xu
- Key
Laboratory of Geographic Information Science of the Ministry of Education,
School of Geographic Sciences, East China
Normal University, Shanghai 200241, China
| | - Yali Lei
- Key
Laboratory of Geographic Information Science of the Ministry of Education,
School of Geographic Sciences, East China
Normal University, Shanghai 200241, China
| | - Gehui Wang
- Key
Laboratory of Geographic Information Science of the Ministry of Education,
School of Geographic Sciences, East China
Normal University, Shanghai 200241, China
- Institute
of Eco-Chongming, Cuiniao
Road, Chenjia Zhen, Chongming, Shanghai 202150, China
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6
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Zheng P, Chen Y, Wang Z, Liu Y, Pu W, Yu C, Xia M, Xu Y, Guo J, Guo Y, Tian L, Qiao X, Huang DD, Yan C, Nie W, Worsnop DR, Lee S, Wang T. Molecular Characterization of Oxygenated Organic Molecules and Their Dominating Roles in Particle Growth in Hong Kong. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:7764-7776. [PMID: 37155674 DOI: 10.1021/acs.est.2c09252] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Oxygenated organic molecules (OOMs) are critical intermediates linking volatile organic compound oxidation and secondary organic aerosol (SOA) formation. Yet, the understanding of OOM components, formation mechanism, and impacts are still limited, especially for urbanized regions with a cocktail of anthropogenic emissions. Herein, ambient measurements of OOMs were conducted at a regional background site in South China in 2018. The molecular characteristics of OOMs revealed dominant nitrogen-containing products, and the influences of different factors on OOM composition and oxidation state were elucidated. Positive matrix factorization analysis resolved the complex OOM species to factors featured with fingerprint species from different oxidation pathways. A new method was developed to identify the key functional groups of OOMs, which successfully classified the majority species into carbonyls (8%), hydroperoxides (7%), nitrates (17%), peroxyl nitrates (10%), dinitrates (13%), aromatic ring-retaining species (6%), and terpenes (7%). The volatility estimation of OOMs was improved based on their identified functional groups and was used to simulate the aerosol growth process contributed by the condensation of those low-volatile OOMs. The results demonstrate the predominant role of OOMs in contributing sub-100 nm particle growth and SOA formation and highlight the importance of dinitrates and anthropogenic products from multistep oxidation.
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Affiliation(s)
- Penggang Zheng
- Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR 999077, China
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR 999077, China
| | - Yi Chen
- Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR 999077, China
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR 999077, China
| | - Zhe Wang
- Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR 999077, China
| | - Yuliang Liu
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing 210023, China
| | - Wei Pu
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR 999077, China
| | - Chuan Yu
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR 999077, China
| | - Men Xia
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR 999077, China
| | - Yang Xu
- Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR 999077, China
| | - Jia Guo
- Environmental Central Facility, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR 999077, China
| | - Yishuo Guo
- Aerosol and Haze Laboratory, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100084, China
| | - Linhui Tian
- Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Taipa, Macau 999078, China
| | - Xiaohui Qiao
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Dan Dan Huang
- State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Chao Yan
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing 210023, China
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki 00014, Finland
| | - Wei Nie
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing 210023, China
| | - Douglas R Worsnop
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki 00014, Finland
- Aerodyne Research Inc., Billerica, Massachusetts 01821, United States
| | - Shuncheng Lee
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR 999077, China
| | - Tao Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR 999077, China
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7
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Li H, Cui L, Huang Y, Zhang Y, Wang J, Chen M, Ge X. Concurrent dominant pathways of multifunctional products formed from nocturnal isoprene oxidation. CHEMOSPHERE 2023; 322:138185. [PMID: 36812999 DOI: 10.1016/j.chemosphere.2023.138185] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 02/06/2023] [Accepted: 02/17/2023] [Indexed: 06/18/2023]
Abstract
Determination of dominant chemical pathways toward the formation of nocturnal secondary organic aerosols (SOA) remains ambiguous by which nitrogen oxides (NOx) always affect oxidation of volatile alkenes. Here, comprehensive chamber simulations on dark isoprene ozonolysis were conducted under different nitrogen dioxides (NO2) mixing ratios to exam multiple functionalized isoprene oxidation products. Aside from that the oxidation processes were concurrently driven by nitrogen radical (NO3) and small hydroxyl radicals (OH), ozone (O3) cycloaddition at isoprene was launched initially regardless of NO2 to rapidly form first-generation oxidation products, i.e., carbonyls and Criegee intermediates (CI) referred to carbonyl oxides. They could further undergo complicated self- and cross-reactions to produce alkylperoxy radicals (RO2). Corresponding to yields of the C5H10O3 tracer, weak OH pathway at night was credited to ozonolysis of isoprene but suppressed by unique NO3 chemistry. Following the ozonolysis of isoprene, NO3 played a crucial supplementary role in nighttime SOA formation. The ensuing production of gas-phase nitrooxy carbonyls (the first-generation nitrates) became dominant in the production of a sizeable pool of organic nitrates (RO2NO2). By contrast, isoprene dihydroxy dinitrates (C5H10N2O8) were outstanding with the elevated NO2, related to typical second-generation nitrates. As such, the yielding number concentrations of dark SOA were promoted to approximately 1.8 × 104 cm-3 but presented a nonlinear relation with excess high-NO2 condition. This study provides valuable insights into importance of multifunctional organic compounds from alkene oxidation to constitute nighttime SOA.
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Affiliation(s)
- Haiwei Li
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Long Cui
- State Key Laboratory of Loess and Quaternary Geology (SKLLQG) and Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Yu Huang
- State Key Laboratory of Loess and Quaternary Geology (SKLLQG) and Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Yunjiang Zhang
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Junfeng Wang
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Mindong Chen
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Xinlei Ge
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Sciences and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China.
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8
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Peng Y, Yuan B, Yang S, Wang S, Yang X, Wang W, Li J, Song X, Wu C, Qi J, Zheng E, Ye C, Huang S, Hu W, Song W, Wang X, Wang B, Shao M. Photolysis frequency of nitrophenols derived from ambient measurements. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 869:161810. [PMID: 36702278 DOI: 10.1016/j.scitotenv.2023.161810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 01/02/2023] [Accepted: 01/20/2023] [Indexed: 06/18/2023]
Abstract
Nitrophenols, a class of important intermediate products from the oxidation of aromatics, can participate in photochemistry and influence the atmospheric oxidative capacity. However, the reported photolysis frequencies of nitrophenols show considerable discrepancies. Here, measurements of nitrophenol, and methyl nitrophenol using a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) at both urban and regional sites in southern China are used to constrain photolysis frequencies of nitrophenols. Considerable concentrations with a campaign average of 58 ± 32 ppt for nitrophenol and 97 ± 59 ppt for methyl nitrophenol were observed at the regional site. Based on the in-situ measurement dataset, a steady-state calculation was performed along with a zero-dimensional box model to analyze the budgets of nitrophenols. The result indicates that both primary emission and photolysis have significant impacts on nitrophenols. Primary emission contributes up to 88 % of the total nitrophenols production while photolysis accounts for up to 98 % of the total removal rate. The dominant sink of nitrophenols is photolysis with a rate of about 3.5 % ± 1.3 % of jNO2 for nitrophenol and 2.4 % ± 1.0 % of jNO2 for methyl nitrophenol. The results of this study suggest that using advanced mass spectrometry to accurately measure ambient nitrophenols, supplemented by an observation-based box model for budget analysis, provides an important indication for determining photolysis rate constants of nitrophenols.
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Affiliation(s)
- Yuwen Peng
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - Bin Yuan
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China.
| | - Suxia Yang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - Sihang Wang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - Xiaoyun Yang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - Wenjie Wang
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz 55128, Germany
| | - Jin Li
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - Xin Song
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - Caihong Wu
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - Jipeng Qi
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - E Zheng
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - Chenshuo Ye
- Guangdong Provincial Academy of Environmental Science, Guangzhou 510045, China
| | - Shan Huang
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - Weiwei Hu
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Wei Song
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Xinming Wang
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Baolin Wang
- School of Environmental Science and Engineering, Qilu University of Technology, Jinan 250353, China
| | - Min Shao
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
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9
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Wang F, Liu X, Lv S, Zhang S, Wu C, Liu S, Lei Y, Chen Y, Li R, Wang G. Increasing role of phenolic oxidative branch in daytime oxidation process of aromatics in Chinese haze period. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159578. [PMID: 36270370 DOI: 10.1016/j.scitotenv.2022.159578] [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: 09/05/2022] [Revised: 10/15/2022] [Accepted: 10/15/2022] [Indexed: 06/16/2023]
Abstract
To understand the photooxidation mechanisms of aromatic compounds in the NOx-rich atmosphere, gaseous aromatics and their oxidization products (i.e., methyl glyoxal (MGLY), and nitrated phenols (NPs) including nitrophenols (NPhs) and methylnitrophenols (MNPs)) were measured with a 1-h time resolution on Chongming Island, a downwind region of the Yangtze River Delta (YRD) metropolitans of China in winter 2019 by using a proton-transfer-reaction mass spectrometer (PTR-MS). During the entire observation period, concentrations of the measured VOCs were 9.6 ± 7.1 ppbv for aromatics, 118 ± 59 pptv for MGLY, 36 ± 10 pptv for NPhs, and 9.3 ± 2.8 pptv for MNPs, respectively. Secondary NPs (SNPs) accounted for only 19-24 % of the total nitrated phenols during the clean and transition periods but increased to 44 % of the total on the hazy days. Moreover, the daytime mixing ratios of SNPs increased along with an increasing NO2 concentration during the clean and transition periods, but in the haze period the daytime SNPs first increased along with the increasing NO2 levels and then increased much more sharply when NO2 was >25 ppbv. Such highly proportional and sharply increased daytime SNPs in the haze period indicated an enhanced phenolic oxidation under the high NOx conditions. In addition, the lack of correlations between aromatics and MGLY, increased MGLYaro (MGLY produced by aromatics), and sharply increased ΔSNPs / Δ(benzene + toluene) further suggested that such an increasing role of the phenolic oxidative branch in the daytime oxidation process of aromatics during the YRD haze period was caused by the strong atmospheric oxidation capacity and the high level of NOx.
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Affiliation(s)
- Fanglin Wang
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Xiaodi Liu
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Shaojun Lv
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Si Zhang
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Can Wu
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Shijie Liu
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Yali Lei
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Yubao Chen
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Rui Li
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Gehui Wang
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China; Institute of Eco-Chongming, Chenjia Zhen, Chongming, Shanghai 202150, China.
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10
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Li F, Zhou S, Du L, Zhao J, Hang J, Wang X. Aqueous-phase chemistry of atmospheric phenolic compounds: A critical review of laboratory studies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:158895. [PMID: 36130630 DOI: 10.1016/j.scitotenv.2022.158895] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/12/2022] [Accepted: 09/16/2022] [Indexed: 06/15/2023]
Abstract
Phenolic compounds (PhCs) are crucial atmospheric pollutants typically emitted by biomass burning and receive particular concerns considering their toxicity, light-absorbing properties, and involvement in secondary organic aerosol (SOA) formation. A comprehensive understanding of the transformation mechanisms on chemical reactions in atmospheric waters (i.e., cloud/fog droplets and aerosol liquid water) is essential to predict more precisely the atmospheric fate and environmental impacts of PhCs. Laboratory studies play a core role in providing the fundamental knowledge of aqueous-phase chemical transformations in the atmosphere. This article critically reviews recent laboratory advances in SOA formation from the aqueous-phase reactions of PhCs. It focuses primarily on the aqueous oxidation of PhCs driven by two atmospheric reactive species: OH radicals and triplet excited state organics, including the important chemical kinetics and mechanisms. The effects of inorganic components (i.e., nitrate and nitrite) and transition metal ions (i.e., soluble iron) are highlighted on the aqueous-phase transformation of PhCs and on the properties and formation mechanisms of SOA. The review is concluded with the current knowledge gaps and future perspectives for a better understanding of the atmospheric transformation and SOA formation potential of PhCs.
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Affiliation(s)
- Fenghua Li
- School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China
| | - Shengzhen Zhou
- School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China; Guangdong Provincial Field Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Sun Yat-sen University, Guangzhou 510275, China; Key Laboratory of Tropical Atmosphere-Ocean System, Ministry of Education, Zhuhai 519082, China.
| | - Lin Du
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Jun Zhao
- School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China; Guangdong Provincial Field Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Sun Yat-sen University, Guangzhou 510275, China; Key Laboratory of Tropical Atmosphere-Ocean System, Ministry of Education, Zhuhai 519082, China
| | - Jian Hang
- School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China; Guangdong Provincial Field Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Sun Yat-sen University, Guangzhou 510275, China; Key Laboratory of Tropical Atmosphere-Ocean System, Ministry of Education, Zhuhai 519082, China
| | - Xuemei Wang
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Institute for Environmental and Climate Research, Jinan University, Guangzhou 510000, China
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11
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Wang F, Lv S, Liu X, Lei Y, Wu C, Chen Y, Zhang F, Wang G. Investigation into the differences and relationships between gasSOA and aqSOA in winter haze pollution on Chongming Island, Shanghai, based on VOCs observation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 316:120684. [PMID: 36400138 DOI: 10.1016/j.envpol.2022.120684] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/08/2022] [Accepted: 11/14/2022] [Indexed: 06/16/2023]
Abstract
To investigate the formation of secondary organic aerosol (SOA) under current atmospheric conditions, we conducted a field observation of SOA precursors in the downwind region of the Yangtze River Delta (YRD) in winter 2019 using a variety of offline and online instruments. During the entire observation period, the averaged fine particulate SOA was 7.9 ± 2.3 μg m-3, with precursor concentrations of 31 ± 11 ppbv for the measured volatile organic compounds (VOCs) and 16 ± 12 ppbv for NOx. Compared to those on the clean days, SOA on the haze days increased by a factor of 1.6, while the VOC and NOx increased by a factor of 1.3 and 2.0, respectively. Aerosol liquid water content (ALWC) and oxygenated VOCs (OVOCs, including acetaldehyde, formic acid, acetone, acetic acid, methyl ethyl ketone, and methylglyoxal) relationships suggested that the gasSOA and aqSOA occurred simultaneously on Chongming Island in winter. The gasSOA was primarily formed by the oxidation of aromatics and NOx at low RH (RH < 80%) conditions. In contrast, the aqSOA was formed under higher RH (RH > 80%) conditions via a combination of daytime photochemical aqueous phase processes of water-soluble OVOCs and nocturnal dark aqueous phase processes of primary emissions from biomass. The inversed higher mass ratio of NACs to (benzene + toluene) and nitrogen oxidation ratio (NOR) in the daytime during the gasSOA-dominated haze periods indicated that gasSOA could be transformed to aqSOA at high NOx levels. Our results also suggested the importance of NOx and VOC reduction measures in directly mitigating gasSOA and indirectly mitigating aqSOA during winter haze pollution.
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Affiliation(s)
- Fanglin Wang
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China
| | - Shaojun Lv
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China
| | - Xiaodi Liu
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China
| | - Yali Lei
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China
| | - Can Wu
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China
| | - Yubao Chen
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China
| | - Fan Zhang
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China
| | - Gehui Wang
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 200062, China; Institute of Eco-Chongming, Chenjia Zhen, Chongming, Shanghai, 202162, China.
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12
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Chen Y, Tan Y, Zheng P, Wang Z, Zou Z, Ho KF, Lee S, Wang T. Effect of NO 2 on nocturnal chemistry of isoprene: Gaseous oxygenated products and secondary organic aerosol formation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 842:156908. [PMID: 35753484 DOI: 10.1016/j.scitotenv.2022.156908] [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: 05/05/2022] [Revised: 06/15/2022] [Accepted: 06/19/2022] [Indexed: 06/15/2023]
Abstract
As one of the most abundant non-methane hydrocarbon in the atmosphere, isoprene has attracted lots of attention on its oxidation processes and environmental effects. However, less is known about the nocturnal chemistry of isoprene with multiple oxidants coexisting in the atmosphere. Besides, though highly oxygenated molecules (HOMs) have recently been recognized to contribute to secondary organic aerosol (SOA) formation, the specific contribution of measured HOMs on SOA formation in isoprene oxidation has not been well established. In this study, the oxidation of isoprene was simulated under dark and various NO2/O3 conditions. Plenty of oxidation products were identified by combining two state-of-the-art time-of-flight mass spectrometers, and more species with high C and N numbers and low volatilities were detected under high NO2 conditions. The nocturnal oxidation of isoprene was found to be governed by synergic effects of multiple oxidants, including O3, NO3•, and •OH at the same time, and the oxidation proportions changed with NO2. NO2 promoted the formation of most N-containing products especially N2 products, because of the decisive role of NO3• on their formation. Nevertheless, some products such as C5H10O3-5, C5H11NO6, and C10H16N2O10,11 showed a better correlation with HO2NO2 rather than NO2/O3, indicating the importance of HO2• chemistry on the oxidation products formation. Though the concentration of measured oxygenated products was dominated by volatile and semi-volatile organic compounds, the low- and extremely low-volatile organic compounds contributed over 97 % to the SOA formation potential. However, challenges still exist in accurately simulating SOA formation from the measured oxygenated molecules to match the measurement, and further comprehensive characterization of oxidation products in both gas and aerosol phases at the molecular level is needed.
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Affiliation(s)
- Yi Chen
- Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong 999077, China; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China
| | - Yan Tan
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China; School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, China
| | - Penggang Zheng
- Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong 999077, China
| | - Zhe Wang
- Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong 999077, China.
| | - Zhouxing Zou
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China
| | - Kin-Fai Ho
- The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong 999077, China
| | - Shuncheng Lee
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China.
| | - Tao Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China
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13
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Jiang X, Liu D, Li Q, Tian P, Wu Y, Li S, Hu K, Ding S, Bi K, Li R, Huang M, Ding D, Chen Q, Kong S, Li W, Pang Y, He D. Connecting the Light Absorption of Atmospheric Organic Aerosols with Oxidation State and Polarity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:12873-12885. [PMID: 36083258 DOI: 10.1021/acs.est.2c02202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The light-absorbing organic aerosol (OA) constitutes an important fraction of absorbing components, counteracting major cooling effect of aerosols to climate. The mechanisms in linking the complex and changeable chemistry of OA with its absorbing properties remain to be elucidated. Here, by using solvent extraction, ambient OA from an urban environment was fractionated according to polarity, which was further nebulized and online characterized with compositions and absorbing properties. Water extracted high-polar compounds with a significantly higher oxygen to carbon ratio (O/C) than methanol extracts. A transition O/C of about 0.6 was found, below and above which the enhancement and reduction of OA absorptivity were observed with increasing O/C, occurring on the less polar and high polar compounds, respectively. In particular, the co-increase of nitrogen and oxygen elements suggests the important role of nitrogen-containing functional groups in enhancing the absorptivity of the less polar compounds (e.g., forming nitrogen-containing aromatics), while further oxidation (O/C > 0.6) on high-polar compounds likely led to fragmentation and bleaching chromophores. The results here may reconcile the previous observations about darkening or whitening chromophores of brown carbon, and the parametrization of O/C has the potential to link the changing chemistry of OA with its polarity and absorbing properties.
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Affiliation(s)
- Xiaotong Jiang
- Department of Atmospheric Science, School of Earth Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Dantong Liu
- Department of Atmospheric Science, School of Earth Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Qian Li
- Department of Atmospheric Science, School of Earth Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Ping Tian
- Beijing Key Laboratory of Cloud, Precipitation and Atmospheric Water Resources, 44 Zizhuyuan Road, Beijing 100089, China
| | - Yangzhou Wu
- Department of Atmospheric Science, School of Earth Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Siyuan Li
- Department of Atmospheric Science, School of Earth Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Kang Hu
- Department of Atmospheric Science, School of Earth Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Shuo Ding
- Department of Atmospheric Science, School of Earth Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Kai Bi
- Beijing Key Laboratory of Cloud, Precipitation and Atmospheric Water Resources, 44 Zizhuyuan Road, Beijing 100089, China
| | - Ruijie Li
- Beijing Key Laboratory of Cloud, Precipitation and Atmospheric Water Resources, 44 Zizhuyuan Road, Beijing 100089, China
| | - Mengyu Huang
- Beijing Key Laboratory of Cloud, Precipitation and Atmospheric Water Resources, 44 Zizhuyuan Road, Beijing 100089, China
| | - Deping Ding
- Beijing Key Laboratory of Cloud, Precipitation and Atmospheric Water Resources, 44 Zizhuyuan Road, Beijing 100089, China
| | - Qingcai Chen
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, 6 Xuefuzhong Road, Xi'an 710021, China
| | - Shaofei Kong
- Department of Atmospheric Science, School of Environmental Science, China University of Geosciences, 388 Lumo Road, Wuhan 430074, China
| | - Weijun Li
- Department of Atmospheric Science, School of Earth Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Yu Pang
- Organic Geochemistry Unit, School of Earth Science, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Ding He
- Department of Ocean Science and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, Hong Kong, SAR 999077, China
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