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Huang S, Shen Z, Yang X, Bai G, Zhang L, Zeng Y, Sun J, Xu H, Ho SSH, Zhang Y, Cao J. Nitroaromatic compounds in six major Chinese cities: Influence of different formation mechanisms on light absorption properties. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 930:172672. [PMID: 38663628 DOI: 10.1016/j.scitotenv.2024.172672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Revised: 04/19/2024] [Accepted: 04/19/2024] [Indexed: 05/05/2024]
Abstract
Nitroaromatic compounds (NACs) are important nitrogen organics in aerosol with strong light-absorbing and chemically reactive properties. In this study, NACs in six Chinese megacities, including Harbin (HB), Beijing (BJ), Xi'an (XA), Wuhan (WH), Chengdu (CD), and Guangzhou (GZ), were investigated for understanding their sources, gas-particle partitioning, and impact on BrC absorption properties. The concentrations of ΣNACs in PM2.5 in the six cities ranged from 9.15 to 158.8 ng/m3 in winter and from 2.02 to 9.39 ng/m3 in summer. Nitro catechols (NCs), nitro phenols (NPs), and nitro salicylic acids (NSAs) are the main components in ΣNACs, with NCs being dominant in particulate phase and NPs being dominant in the gas phase. Correlation analysis between different pollutant species revealed that coal and biomass combustions were the major sources of NACs in the northern cities during wintertime, while secondary formation dominated NACs in the southern cities during summertime. The contribution of ΣNACs to brown carbon (BrC) light absorption ranged from 0.85 to 7.98 % during the wintertime and 2.07-6.44 % during the summertime. The mass absorption efficiency at 365 nm (MAE365) were highest for 4-nitrocatechol (4NC, 17.4-89.0 m2/g), 4-methyl-5-nitrocatechol (4M5NC, 15.0-76.9 m2/g), and 4-nitroguaiacol (4NG, 11.7-59.8 m2/g). The formation of NCs and NG through oxidation and nitration of catechol and guaiacol led to a significant increase in aerosol light absorption. In contrast, NPs and NSAs formed by the photonitration and photooxidation in liquid phase showed high polarity but low light absorption ability, and the proportions of (NPs + NSAs) in the light absorption of ΣNACs were lower than 15.3 % in the six megacities.
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Affiliation(s)
- Shasha Huang
- Department of Environmental Sciences and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Zhenxing Shen
- Department of Environmental Sciences and Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
| | - Xueting Yang
- Department of Environmental Sciences and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Gezi Bai
- Department of Environmental Sciences and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Leiming Zhang
- Air Quality Research Division, Science and Technology Branch, Environment and Climate Change Canada, Toronto, Canada
| | - Yaling Zeng
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jian Sun
- Department of Environmental Sciences and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Hongmei Xu
- Department of Environmental Sciences and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Steven Sai Hang Ho
- Division of Atmospheric Sciences, Desert Research Institute, Reno NV89512, United States
| | - Ying Zhang
- Instruments Analysis Center of Xi'an Jiaotong University, Xi'an 710049, China
| | - Junji Cao
- Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
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Leung CW, Wang X, Hu D. Characteristics and source apportionment of water-soluble organic nitrogen (WSON) in PM 2.5 in Hong Kong: With focus on amines, urea, and nitroaromatic compounds. JOURNAL OF HAZARDOUS MATERIALS 2024; 469:133899. [PMID: 38430595 DOI: 10.1016/j.jhazmat.2024.133899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/23/2024] [Accepted: 02/24/2024] [Indexed: 03/05/2024]
Abstract
Water-soluble organic nitrogen (WSON) is ubiquitous in fine particulate matter (PM2.5) and poses health and environmental risks. However, there is limited knowledge regarding its comprehensive speciation and source-specific contributions. Here, we conducted chemical characterization and source apportionment of WSON in 65 PM2.5 samples collected in Hong Kong during a 1-yr period. Using various mass-spectrometry-based techniques, we quantified 22 nitrogen-containing organic compounds (NOCs), including 17 nitroaromatics (NACs), four amines, and urea. The most abundant amine and NACs were dimethylamine and 4-nitrocatechol, respectively. Two secondary (i.e., secondary formation and secondary nitrate) and five primary sources (i.e., sea salt, fugitive dust, marine vessels, vehicle exhaust, and biomass burning) of WSON and these three categories of NOCs were identified. Throughout the year, secondary sources dominated WSON formation (69.0%), while primary emissions had significant contributions to NACs (77.1%), amines (75.9%), and urea (83.7%). Fugitive dust was the leading source of amines and urea, while biomass burning was the main source of NACs. Our multi-linear regression analysis revealed the significant role of sulfate, NO3, nitrate, liquid water content, and particle pH on WSON formation, highlighting the importance of nighttime NO3 processing and heterogeneous and aqueous-phase formation of NOCs in the Hong Kong atmosphere.
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Affiliation(s)
- Chin Wai Leung
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region of China
| | - Xuemei Wang
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region of China
| | - Di Hu
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region of China; State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Kowloon Tong, Hong Kong Special Administrative Region of China; HKBU Institute of Research and Continuing Education, Shenzhen Virtual University Park, Shenzhen 518057, PR China.
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Cheng Z, Qiu X, Li A, Chai Q, Shi X, Ge Y, Koenig TK, Zheng Y, Chen S, Hu M, Ye C, Cheung RKY, Modini RL, Chen Q, Shang J, Zhu T. Heterogeneous reactions significantly contribute to the atmospheric formation of nitrated aromatic compounds during the haze episode in urban Beijing. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 917:170612. [PMID: 38307269 DOI: 10.1016/j.scitotenv.2024.170612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/21/2024] [Accepted: 01/30/2024] [Indexed: 02/04/2024]
Abstract
Nitrated aromatic compounds (NACs) are key components of air pollution; however, due to the presence of complex mixtures of primary and secondary species, especially in urban environments, their atmospheric formation is poorly understood. Here we conducted a field campaign during a winter haze episode in urban Beijing, China to monitor gaseous and particulate NACs at 2-h time resolution. Through a standard-independent non-targeted approach, a total of 238 NACs were screened, of which 127 species were assigned chemical formula and 25 structures were confirmed. Four main classes were identified: nitrated aromatic hydrocarbons, nitrophenols, oxygenated nitrated aromatic compounds, and nitrated heterocyclic aromatic compounds. Hierarchical clustering analysis revealed disparate temporal variances of diurnal or nocturnal elevation, among which different nitration formations were captured, i.e., daytime photochemical oxidation and nighttime heterogeneous reactions. Isomeric information, particularly the substitution position of the nitro group on biphenyl, further demonstrated a potential heterogeneous mechanism of electrophilic nitration by NO2+. Assisted by source apportionment, we found that nighttime heterogeneous reactions significantly contributed to NAC formation, e.g., 31.3 % and 60.8 %, respectively, to 2-nitrofluoranthene and 2-nitropyrene, which were previously considered as classical daytime gas-phase products. This study provides comprehensive information on urban NAC species and highlights the importance of unheeded heterogeneous reactions in the atmosphere.
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Affiliation(s)
- Zhen Cheng
- SKL-ESPC and SEPKL-AERM, College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, PR China
| | - Xinghua Qiu
- SKL-ESPC and SEPKL-AERM, College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, PR China.
| | - Ailin Li
- SKL-ESPC and SEPKL-AERM, College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, PR China
| | - Qianqian Chai
- SKL-ESPC and SEPKL-AERM, College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, PR China
| | - Xiaodi Shi
- SKL-ESPC and SEPKL-AERM, College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, PR China
| | - Yanli Ge
- SKL-ESPC and SEPKL-AERM, College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, PR China
| | - Theodore K Koenig
- SKL-ESPC and SEPKL-AERM, College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, PR China
| | - Yan Zheng
- SKL-ESPC and SEPKL-AERM, College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, PR China
| | - Shiyi Chen
- SKL-ESPC and SEPKL-AERM, College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, PR China
| | - Min Hu
- SKL-ESPC and SEPKL-AERM, College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, PR China
| | - Chunxiang Ye
- SKL-ESPC and SEPKL-AERM, College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, PR China
| | - Rico K Y Cheung
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Robin L Modini
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Qi Chen
- SKL-ESPC and SEPKL-AERM, College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, PR China
| | - Jing Shang
- SKL-ESPC and SEPKL-AERM, College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, PR China
| | - Tong Zhu
- SKL-ESPC and SEPKL-AERM, College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, PR China
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Peng B, Dong Q, Li F, Wang T, Qiu X, Zhu T. A Systematic Review of Polycyclic Aromatic Hydrocarbon Derivatives: Occurrences, Levels, Biotransformation, Exposure Biomarkers, and Toxicity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:15314-15335. [PMID: 37703436 DOI: 10.1021/acs.est.3c03170] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
Polycyclic aromatic hydrocarbon (PAH) derivatives constitute a significant class of emerging contaminants that have been ubiquitously detected in diverse environmental matrixes, with some even exhibiting higher toxicities than their corresponding parent PAHs. To date, compared with parent PAHs, fewer systematic summaries and reanalyses are available for PAH derivatives with great environmental concerns. This review summarizes the current knowledge on the chemical species, levels, biotransformation patterns, chemical analytical methods, internal exposure routes with representative biomarkers, and toxicity of PAH derivatives, primarily focusing on nitrated PAHs (NPAHs), oxygenated PAHs (OPAHs), halogenated PAHs (XPAHs), and alkylated PAHs (APAHs). A collection of 188 compounds from four categories, 44 NPAHs, 36 OPAHs, 56 APAHs, and 52 XPAHs, has been compiled from 114 studies that documented the environmental presence of PAH derivatives. These compounds exhibited weighted average air concentrations that varied from a lower limit of 0.019 pg/m3 to a higher threshold of 4060 pg/m3. Different analytical methods utilizing comprehensive two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry (GC × GC-TOF-MS), gas chromatography coupled to time-of-flight mass spectrometry (GC-TOF-MS), comprehensive two-dimensional gas chromatography coupled to quadrupole mass spectrometry (GC × GC-QQQ-MS), and Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), that adopted untargeted strategies for the identification of PAH derivatives are also reviewed here. Additionally, an in-depth analysis of biotransformation patterns for each category is provided, including the likelihood of specific biotransformation reaction types. For the toxicity, we primarily summarized key metabolic activation pathways, which could result in the formation of reactive metabolites capable of covalently bonding with DNA and tissue proteins, and potential health outcomes such as carcinogenicity and genotoxicity, oxidative stress, inflammation and immunotoxicity, and developmental toxicity that might be mediated by the aryl hydrocarbon receptor (AhR). Finally, we pinpoint research challenges and emphasize the need for further studies on identifying PAH derivatives, tracking external exposure levels, evaluating internal exposure levels and associated toxicity, clarifying exposure routes, and considering mixture exposure effects. This review aims to provide a broad understanding of PAH derivatives' identification, environmental occurrence, human exposure, biotransformation, and toxicity, offering a valuable reference for guiding future research in this underexplored area.
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Affiliation(s)
- Bo Peng
- SKL-ESPC and College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, China
| | - Qianli Dong
- SKL-ESPC and College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, China
| | - Fangzhou Li
- SKL-ESPC and College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, China
| | - Teng Wang
- SKL-ESPC and College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, China
| | - Xinghua Qiu
- SKL-ESPC and College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, China
| | - Tong Zhu
- SKL-ESPC and College of Environmental Sciences and Engineering, Center for Environment and Health, Peking University, Beijing 100871, China
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