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He S, Liu Y, Song M, Li X, Lu S, Chen T, Mu Y, Lou S, Shi X, Qiu X, Zhu T, Zhang Y. Insights into the Peroxide-Bicyclic Intermediate Pathway of Aromatic Photooxidation: Experimental Yields and NO x-Dependency of Ring-Opening and Ring-Retaining Products. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:20657-20668. [PMID: 38029335 DOI: 10.1021/acs.est.3c05304] [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: 12/01/2023]
Abstract
Aromatic hydrocarbons are important contributors to the formation of ozone and secondary organic aerosols in urban environments. The different parallel pathways in aromatic oxidation, however, remain inadequately understood. Here, we investigated the production yields and chemical distributions of gas-phase tracer products during the photooxidation of alkylbenzenes at atmospheric OH levels with NOx present using high-resolution mass spectrometers. The peroxide-bicyclic intermediate pathway emerged as the major pathway in aromatic oxidation, accounting for 52.1 ± 12.6%, 66.1 ± 16.6%, and 81.4 ± 24.3% of the total OH oxidation of toluene, m-xylene, and 1,3,5-trimethylbenzene, respectively. Notably, the yields of bicyclic nitrates produced from the reactions of bicyclic peroxy radicals (BPRs) with NO were considerably lower (3-5 times) than what the current mechanism predicted. Alongside traditional ring-opening products formed through the bicyclic pathway (dicarbonyls and furanones), we identified a significant proportion of carbonyl olefinic acids generated via the 1,5-aldehydic H-shift occurring in subsequent reactions of BPRs + NO, contributing 4-7% of the carbon flow in aromatic oxidation. Moreover, the observed NOx-dependencies of ring-opening and ring-retaining product yields provide insights into the competitive nature of reactions involving BPRs with NO, HO2, and RO2, which determine the refined product distributions and offer an explanation for the discrepancies between the experimental and model-based results.
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Affiliation(s)
- Shuyu He
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Ying Liu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Mengdi Song
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xin Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Sihua Lu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Tianzeng Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yujing Mu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Shengrong Lou
- State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex, Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Xiaodi Shi
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xinghua Qiu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Tong Zhu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yuanhang Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
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Upshur MA, Bé AG, Luo J, Varelas JG, Geiger FM, Thomson RJ. Organic synthesis in the study of terpene-derived oxidation products in the atmosphere. Nat Prod Rep 2023; 40:890-921. [PMID: 36938683 DOI: 10.1039/d2np00064d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2023]
Abstract
Covering: 1997 up to 2022Volatile biogenic terpenes involved in the formation of secondary organic aerosol (SOA) particles participate in rich atmospheric chemistry that impacts numerous aspects of the earth's complex climate system. Despite the importance of these species, understanding their fate in the atmosphere and determining their atmospherically-relevant properties has been limited by the availability of authentic standards and probe molecules. Advances in synthetic organic chemistry directly aimed at answering these questions have, however, led to exciting discoveries at the interface of chemistry and atmospheric science. Herein we provide a review of the literature regarding the synthesis of commercially unavailable authentic standards used to analyze the composition, properties, and mechanisms of SOA particles in the atmosphere.
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Affiliation(s)
- Mary Alice Upshur
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208, USA.
| | - Ariana Gray Bé
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208, USA.
| | - Jingyi Luo
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208, USA.
| | - Jonathan G Varelas
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208, USA.
| | - Franz M Geiger
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208, USA.
| | - Regan J Thomson
- Department of Chemistry, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208, USA.
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Kuang Y, Shang J, Sheng M, Shi X, Zhu J, Qiu X. Molecular Composition of Beijing PM 2.5 Brown Carbon Revealed by an Untargeted Approach Based on Gas Chromatography and Time-of-Flight Mass Spectrometry. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:909-919. [PMID: 36594719 DOI: 10.1021/acs.est.2c05918] [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] [Indexed: 06/17/2023]
Abstract
The knowledge of the chemical composition of brown carbon (BrC) is limited to the categories of components or parts of specific organic components. In this paper, the light-absorbing properties and molecular compositions of lipid-soluble organic components in fine particulate matter of Beijing from 2016 to 2018, characterized by an ultraviolet-visible spectrometer and gas chromatography coupled with time-of-flight mass spectrometry, respectively, were combined to untargetedly screen the key BrC molecules by a partial least squares regression model for the first time. A total of 421 molecules were obtained, where 61 molecules were identified qualitatively and 22 molecules quantitatively. To the best of our knowledge, 11 molecules were newly identified BrC species. These qualitative molecules included polycyclic aromatic hydrocarbons with higher ambient concentrations and mass absorbing efficiencies (MAEs), as well as oxygen- and nitrogen-containing aromatic components with relatively lower concentrations and MAEs. The absorption contribution at 365 nm of quantified BrC species to lipid-soluble BrC during heating seasons was 39.1 ± 17.0%, which was about 5 times as high as previous studies. These results help establish a complete BrC molecular database and provide data support for better evaluating the climate effect of atmospheric carbonaceous aerosols and formulating air pollution control strategies.
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Affiliation(s)
- Yu Kuang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Jing Shang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Mengshuang Sheng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Xiaodi Shi
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Jiali Zhu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Xinghua Qiu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, People's Republic of China
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Ning C, Gao Y, Zhang H, Wang L, Yu H, Zou L, Cao R, Chen J. Molecular chemodiversity of water-soluble organic matter in atmospheric particulate matter and their associations with atmospheric conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 809:151171. [PMID: 34699831 DOI: 10.1016/j.scitotenv.2021.151171] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
Water-soluble organic matter (WSOM) is a complex mixture of organic compounds affecting global climate change and carbon cycle. Herein, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used for identification of WSOM molecular compositions in annual atmospheric particulate matter with diameters ≤10 μm (PM10). Totally 6538 unambiguous monoisotopic molecular formulas were assigned to WSOM with m/z values concentrating in 150-600 Da. The CHO compounds with high unsaturation degrees contributed most (51.7-52.1%) to WSOM in spring and summer. However, the S-containing compounds (CHOS and CHNOS) with higher O/C and H/C ratios accounted for 56.8-63.2% of WSOM in autumn and winter. Temperature (r = 0.82) and O3 (r = 0.89) showed higher correlation with CHO compounds, which were mainly aliphatics and highly unsaturated structures with high oxygen compounds (80.7-90.8%). The concentrations of SO42- (r = 0.33) and NO3- (r = 0.46) in PM10 both showed a positive correlation with the abundances of the S-containing compounds due to their direct participation in atmospheric reactions. Among them, 96-100% and 78-96% of the CHOS and CHNOS compounds were confirmed to be organosulfates (OSs) and nitrooxy-organosulfates (NOSs) by MS/MS analysis, respectively. These findings illustrate the strong association of atmospheric conditions with molecular chemodiversity of WSOM.
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Affiliation(s)
- Cuiping Ning
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuan Gao
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
| | - Haijun Zhang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Lei Wang
- MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Haoran Yu
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lili Zou
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Rong Cao
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Jiping Chen
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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Kenagy HS, Romer Present PS, Wooldridge PJ, Nault BA, Campuzano-Jost P, Day DA, Jimenez JL, Zare A, Pye HOT, Yu J, Song CH, Blake DR, Woo JH, Kim Y, Cohen RC. Contribution of Organic Nitrates to Organic Aerosol over South Korea during KORUS-AQ. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:16326-16338. [PMID: 34870986 PMCID: PMC8759034 DOI: 10.1021/acs.est.1c05521] [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] [Indexed: 06/13/2023]
Abstract
The role of anthropogenic NOx emissions in secondary organic aerosol (SOA) production is not fully understood but is important for understanding the contribution of emissions to air quality. Here, we examine the role of organic nitrates (RONO2) in SOA formation over the Korean Peninsula during the Korea-United States Air Quality field study in Spring 2016 as a model for RONO2 aerosol in cities worldwide. We use aircraft-based measurements of the particle phase and total (gas + particle) RONO2 to explore RONO2 phase partitioning. These measurements show that, on average, one-fourth of RONO2 are in the condensed phase, and we estimate that ≈15% of the organic aerosol (OA) mass can be attributed to RONO2. Furthermore, we observe that the fraction of RONO2 in the condensed phase increases with OA concentration, evidencing that equilibrium absorptive partitioning controls the RONO2 phase distribution. Lastly, we model RONO2 chemistry and phase partitioning in the Community Multiscale Air Quality modeling system. We find that known chemistry can account for one-third of the observed RONO2, but there is a large missing source of semivolatile, anthropogenically derived RONO2. We propose that this missing source may result from the oxidation of semi- and intermediate-volatility organic compounds and/or from anthropogenic molecules that undergo autoxidation or multiple generations of OH-initiated oxidation.
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Affiliation(s)
- Hannah S Kenagy
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Paul S Romer Present
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Paul J Wooldridge
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Benjamin A Nault
- 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
| | - Pedro Campuzano-Jost
- 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
| | - Douglas A Day
- 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
| | - Jose L Jimenez
- 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
| | - Azimeh Zare
- Department of Chemistry, University of California, Berkeley, California 94710, United States
| | - Havala O T Pye
- Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, Durham, North Carolina 27709, United States
| | - Jinhyeok Yu
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61105, Republic of Korea
| | - Chul H Song
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61105, Republic of Korea
| | - Donald R Blake
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Jung-Hun Woo
- Department of Civil and Environmental Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Younha Kim
- Energy, Climate, and Environment (ECE) Program, International Institute for Applied Systems Analysis (IIASA), Laxenburg A-2361, Austria
| | - Ronald C Cohen
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Department of Earth & Planetary Sciences, University of California, Berkeley CA 94 720, United States
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Zheng Y, Chen Q, Cheng X, Mohr C, Cai J, Huang W, Shrivastava M, Ye P, Fu P, Shi X, Ge Y, Liao K, Miao R, Qiu X, Koenig TK, Chen S. Precursors and Pathways Leading to Enhanced Secondary Organic Aerosol Formation during Severe Haze Episodes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:15680-15693. [PMID: 34775752 DOI: 10.1021/acs.est.1c04255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Molecular analyses help to investigate the key precursors and chemical processes of secondary organic aerosol (SOA) formation. We obtained the sources and molecular compositions of organic aerosol in PM2.5 in winter in Beijing by online and offline mass spectrometer measurements. Photochemical and aqueous processing were both involved in producing SOA during the haze events. Aromatics, isoprene, long-chain alkanes or alkenes, and carbonyls such as glyoxal and methylglyoxal were all important precursors. The enhanced SOA formation during the severe haze event was predominantly contributed by aqueous processing that was promoted by elevated amounts of aerosol water for which multifunctional organic nitrates contributed the most followed by organic compounds having four oxygen atoms in their formulae. The latter included dicarboxylic acids and various oxidation products from isoprene and aromatics as well as products or oligomers from methylglyoxal aqueous uptake. Nitrated phenols, organosulfates, and methanesulfonic acid were also important SOA products but their contributions to the elevated SOA mass during the severe haze event were minor. Our results highlight the importance of reducing nitrogen oxides and nitrate for future SOA control. Additionally, the formation of highly oxygenated long-chain molecules with a low degree of unsaturation in polluted urban environments requires further research.
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Affiliation(s)
- Yan Zheng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, BIC-ESAT and IJRC, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Qi Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, BIC-ESAT and IJRC, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xi Cheng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, BIC-ESAT and IJRC, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Claudia Mohr
- Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm 11418, Sweden
| | - Jing Cai
- Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, Helsinki 00014, Finland
| | - Wei Huang
- Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, Helsinki 00014, Finland
| | - Manish Shrivastava
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Penglin Ye
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China
| | - Pingqing Fu
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China
| | - Xiaodi Shi
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, BIC-ESAT and IJRC, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yanli Ge
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, BIC-ESAT and IJRC, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Keren Liao
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, BIC-ESAT and IJRC, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Ruqian Miao
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, BIC-ESAT and IJRC, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xinghua Qiu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, BIC-ESAT and IJRC, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Theodore K Koenig
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, BIC-ESAT and IJRC, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Shiyi Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, BIC-ESAT and IJRC, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
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Shi X, Qiu X, Jiang X, Rudich Y, Zhu T. Comprehensive detection of nitrated aromatic compounds in fine particulate matter using gas chromatography and tandem mass spectrometry coupled with an electron capture negative ionization source. JOURNAL OF HAZARDOUS MATERIALS 2021; 407:124794. [PMID: 33338805 DOI: 10.1016/j.jhazmat.2020.124794] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 11/18/2020] [Accepted: 12/04/2020] [Indexed: 06/12/2023]
Abstract
Nitrated aromatic compounds (NACs) are toxic and allergenic airborne pollutants from both primary emissions and atmospheric reactions of aromatics with NO2. A comprehensive investigation of NACs is challenging given their low ambient levels. By applying gas chromatography and tandem mass spectrometry coupled with an electron capture negative ionization source, this study achieved a comprehensive high-throughput and standard-independent detection of nonpolar NACs in fine particulate matter (PM2.5) sampled over 2 years in Beijing, China. Overall, 1047 NACs were detected, among which, the elemental composition of 128 species were derived using time-of-flight mass spectrometry, and 25 species were confirmed using reference standards. In addition to mono-nitrated polycyclic aromatic hydrocarbons (NPAHs), di-nitrated PAHs and alkylated and oxygenated NPAHs were found. Cluster analysis suggested these compounds were derived from various sources particularly atmospheric reactions. We found that the annual levels of primary NPAHs decreased by 46.3-54.8% from 2012-2013 to 2016-2018, though the secondary species did not change significantly after normalization by PM2.5. These results were validated by diagnostic ratios, which indicated an increasing contribution from the secondary formation including nighttime reactions. This novel method for NACs detection may provide valuable insights into the formation mechanisms of NACs in the atmosphere.
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Affiliation(s)
- Xiaodi Shi
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, and Center for Environment and Health, Peking University, Beijing 100871, PR China
| | - Xinghua Qiu
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, and Center for Environment and Health, Peking University, Beijing 100871, PR China.
| | - Xing Jiang
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, and Center for Environment and Health, Peking University, Beijing 100871, PR China
| | - Yinon Rudich
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Tong Zhu
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, and Center for Environment and Health, Peking University, Beijing 100871, PR China
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Cheng Z, Qiu X, Shi X, Zhu T. Identification of organosiloxanes in ambient fine particulate matters using an untargeted strategy via gas chromatography and time-of-flight mass spectrometry. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 271:116128. [PMID: 33421844 DOI: 10.1016/j.envpol.2020.116128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/11/2020] [Accepted: 11/13/2020] [Indexed: 06/12/2023]
Abstract
Organosilicons are widely used in consumer products and are ubiquitous in living environments. However, there is little systemic information on this group of pollutants in ambient particles. This study proposes a novel untargeted strategy based mainly on the mass difference of three silicon isotopes to screen organosilicon compounds from 2-year PM2.5 samples of Beijing using gas chromatography and high-resolution time-of-flight mass spectrometry. 61 organosilicons were filtered from 1019 peaks, and 35 ones were identified as organosiloxanes including 17 methylsiloxanes and 18 phenylmethylsiloxanes, of which 6 and 3 species were confirmed using reference standards, respectively. These organosiloxanes could be clustered into three groups: low-silicon-number methylsiloxanes, high-silicon-number methylsiloxanes, and phenylmethylsiloxanes. Low-silicon-number methylsiloxanes showed high abundance in the heating season but low abundance in the non-heating season, whereas high-silicon-number methylsiloxanes showed the opposite seasonal variation. This study provides a promising strategy for screening organosilicon compounds through an untargeted approach and gives insights for further investigation of the sources and health risks of organosiloxanes.
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Affiliation(s)
- Zhen Cheng
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, And Center for Environment and Health, Peking University, Beijing, 100871, PR China
| | - Xinghua Qiu
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, And Center for Environment and Health, Peking University, Beijing, 100871, PR China.
| | - Xiaodi Shi
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, And Center for Environment and Health, Peking University, Beijing, 100871, PR China
| | - Tong Zhu
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, And Center for Environment and Health, Peking University, Beijing, 100871, PR China
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9
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Shi X, Qiu X, Chen Q, Chen S, Hu M, Rudich Y, Zhu T. Organic Iodine Compounds in Fine Particulate Matter from a Continental Urban Region: Insights into Secondary Formation in the Atmosphere. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:1508-1514. [PMID: 33443418 DOI: 10.1021/acs.est.0c06703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Atmospheric iodine chemistry can significantly affect the atmospheric oxidation capacity in certain regions. In such processes, particle-phase organic iodine compounds (OICs) are key reservoir species in their loss processes. However, their presence and formation mechanism remain unclear, especially in continental regions. Using gas chromatography and time-of-flight mass spectrometry coupled with both electron capture negative ionization and electron impact sources, this study systematically identified unknown OICs in 2-year samples of ambient fine particulate matter (PM2.5) collected in Beijing, an inland city. We determined the molecular structure of 37 unknown OICs, among which six species were confirmed by reference standards. The higher concentrations for ∑37OICs (median: 280 pg m-3; range: 49.0-770 pg m-3) measured in the heating season indicate intensive coal combustion sources of atmospheric iodine. 1-Iodo-2-naphthol and 4-iodoresorcinol are the most abundant species mainly from primary combustion emission and secondary formation, respectively. The detection of 2- and 4-iodoresorcinols, but not of iodine-substituted catechol/hydroquinone or 5-iodoresorcinol, suggests that they are formed via the electrophilic substitution of resorcinol by hypoiodous acid, a product of the reaction of iodine with ozone. This study reports isomeric information on OICs in continental urban PM2.5 and provides valuable evidence on the formation mechanism of OICs in ambient particles.
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Affiliation(s)
- Xiaodi Shi
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, P. R. China
| | - Xinghua Qiu
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, P. R. China
| | - Qi Chen
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, P. R. China
| | - Shiyi Chen
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, P. R. China
| | - Min Hu
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, P. R. China
| | - Yinon Rudich
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Tong Zhu
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, P. R. China
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