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Ahmed SM, Oumnov RA, Kizilkaya O, Hall RW, Sprunger PT, Cook RL. Role of Electronegativity in Environmentally Persistent Free Radicals (EPFRs) Formation on ZnO. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2024; 128:5179-5188. [PMID: 38567373 PMCID: PMC10983065 DOI: 10.1021/acs.jpcc.3c08231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 02/28/2024] [Accepted: 03/04/2024] [Indexed: 04/04/2024]
Abstract
Environmentally persistent free radicals (EPFRs), a group of emerging pollutants, have significantly longer lifetimes than typical free radicals. EPFRs form by the adsorption of organic precursors on a transition metal oxide (TMO) surface involving electron charge transfer between the organic and TMO. In this paper, dihalogenated benzenes were incorporated to study the role of electronegativity in the electron transfer process to obtain a fundamental knowledge of EPFR formation mechanism on ZnO. Upon chemisorption on ZnO nanoparticles at 250 °C, electron paramagnetic resonance (EPR) confirms the formation of oxygen adjacent carbon-centered organic free radicals with concentrations between 1016 and 1017 spins/g. The radical concentrations show a trend of 1,2-dibromobenzene (DBB) > 1,2-dichlorobenzene (DCB) > 1,2-difluorobenzene (DFB) illustrating the role of electronegativity on the amount of radical formation. X-ray absorption spectroscopy (XAS) confirms the reduction of the Zn2+ metal center, contrasting previous experimental evidence of an oxidative mechanism for ZnO single crystal EPFR formation. The extent of Zn reduction for the different organics (DBB > DCB > DFB) also correlates to their polarity. DFT calculations provide theoretical evidence of ZnO surface reduction and exhibit a similar trend of degree of reduction for different organics, further building on the experimental findings. The lifetimes of the EPFRs formed confirm a noteworthy persistency.
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Affiliation(s)
- Syed Monjur Ahmed
- Department
of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Reuben A. Oumnov
- Department
of Natural Sciences and Mathematics, Dominican
University of California, San Rafael, California 94901, United States
| | - Orhan Kizilkaya
- Center for
Advanced Microstructures and Devices, Louisiana
State University, 6980
Jefferson Highway, Baton Rouge, Louisiana 70806, United States
| | - Randall W. Hall
- Department
of Natural Sciences and Mathematics, Dominican
University of California, San Rafael, California 94901, United States
| | - Phillip T. Sprunger
- Center for
Advanced Microstructures and Devices, Louisiana
State University, 6980
Jefferson Highway, Baton Rouge, Louisiana 70806, United States
- Department
of Physics and Astronomy, Louisiana State
University, Baton Rouge, Louisiana 70803, United States
| | - Robert L. Cook
- Department
of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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2
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Zhong L, Zhu B, Su W, Liang W, Wang H, Li T, Cao D, Ruan T, Chen J, Jiang G. Molecular characterization of diverse quinone analogs for discrimination of aerosol-bound persistent pyrolytic and photolytic radicals. Sci Bull (Beijing) 2024; 69:612-620. [PMID: 38101961 DOI: 10.1016/j.scib.2023.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/02/2023] [Accepted: 11/24/2023] [Indexed: 12/17/2023]
Abstract
Aerosol-bound organic radicals, including environmentally persistent free radicals (EPFRs), are key components that affect climate, air quality, and human health. While putative structures have been proposed, the molecular characteristics of EPFRs remain unknown. Here, we report a surrogate method to characterize EPFRs in real ambient samples using mass spectrometry. The method identifies chemically relevant oxygenated polycyclic aromatic hydrocarbons (OxPAH) that interconvert with oxygen-centered EPFR (OC-EPFR). We found OxPAH compounds most relevant to OC-EPFRs are structurally rich and diverse quinones, whose diversity is strongly associated with OC-EPFR levels. Both atmospheric oxidation and combustion contributed to OC-EPFR formation. Redundancy analysis and photochemical aging model show pyrolytic sources generated more oxidized OC-EPFRs than photolytic sources. Our study reveals the detailed molecular characteristics of OC-EPFRs and shows that oxidation states can be used to identify the origins of OC-EPFRs, offering a way to track the development and evolution of aerosol particles in the environment.
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Affiliation(s)
- Laijin Zhong
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Bao Zhu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Wenyuan Su
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Wenqing Liang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Haotian Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Tingyu Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Dong Cao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Ting Ruan
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Jianmin Chen
- Department of Environmental Science and Engineering, Institute of Atmospheric Sciences, Fudan University, Shanghai 200438, China
| | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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3
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Li Y, Li X, Wu L, Shi L, Wang S, Fu P, Zhang Y, Lai S. Analysis of amino acid enantiomers in ambient aerosols: Effects and removal of coexistent aerosol matrix. J Environ Sci (China) 2024; 137:732-740. [PMID: 37980055 DOI: 10.1016/j.jes.2023.02.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 02/24/2023] [Accepted: 02/24/2023] [Indexed: 11/20/2023]
Abstract
Amino acids (AAs) including D- and L- enantiomers are a group of organic nitrogen species in ambient aerosol. Due to the low abundances of AAs (level of ng/m3) and the matrix effects by coexistent components, it is challenging to quantify AA enantiomers in ambient aerosols especially under pollution conditions. In this study, we present an optimized method for analyzing AA enantiomers in atmospheric aerosol samples including a pretreatment process and the detection by high performance liquid chromatography coupled to a fluorescence detector (HPLC-FLD). Matrix effects caused by coexistent chemicals on AA enantiomers analysis in ambient aerosol samples were investigated especially for those collected in pollution episodes. The results revealed that the determination of AA enantiomers is significantly affected by the coexistent organic carbon (as a proxy of organic matter) and water-soluble ion of NH4+. To remove the matrix effects, we applied a pretreatment using the solid phase extraction column coupled with alkaline adjustment to sample extract. After pretreatment, 18 AAs including 6 pairs of D- and L-enantiomers (i.e., leucine, isoleucine, valine, alanine, serine, and aspartic acid) can be successfully separated and quantified in aerosol samples by HPLC-FLD. The recoveries are in the range of 67%-106%. This method was successfully applied to the urban aerosol samples from pollution and non-pollution periods for AA enantiomers determination. We suggest that the concentrations of D-AAs and the ratio of D-AA/L-AA are indicative of the contribution of bacterial sources and the influence of biomass burning.
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Affiliation(s)
- Ying Li
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Xiaoying Li
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Libin Wu
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Luhan Shi
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Shan Wang
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; now at Hong Kong University of Science and Technology, Hong Kong 00852, China
| | - Pingqing Fu
- Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin 300072, China
| | - Yingyi Zhang
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
| | - Senchao Lai
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
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4
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Zhang X, Wang Y, Yao K, Zheng H, Guo H. Oxidative potential, environmentally persistent free radicals and reactive oxygen species of size-resolved ambient particles near highways. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 341:122858. [PMID: 37967708 DOI: 10.1016/j.envpol.2023.122858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 10/30/2023] [Accepted: 11/01/2023] [Indexed: 11/17/2023]
Abstract
Particulate matter (PM) is a group of atmospheric pollutants with an uncertain toxicity, particularly when collected near highways. This study examined the oxidative potential (OP) of, as well as the environmentally persistent free radicals (EPFRs) and reactive oxygen species (ROS) present in PM samples collected near highways in Xiamen, China. Our findings revealed that PM had a relatively high OP, ranging from 3.8 to 18.5 nmol/min/μg, surpassing values reported in previous research. The oxidative potential of the water-insoluble fraction (OPWIS), which accounted for 68% of the total oxidative potential (OPTotal), demonstrated rapid toxicity, whereas the oxidative potential of the water-soluble fraction (OPWS) displayed a steadier toxicity release pattern. The primary free radicals detected in PM were oxygen-centered. The measured concentration of EPFRs was 6.073 × 1014 spins/m3, which is lower than that reported in previous studies, possibly because of the high relative humidity of the road environment in Xiamen. We also investigated the interaction between PM and water near highways and observed the generation of R and OH radicals. Additionally, we analysed the sample composition and evaluated the contributions of the different components to OPTotal. Transition metals (Fe, Cu, and Zn) were identified as the major contributors, accounting for 33.2% of the OPTotal. The positive correlation observed between EPFRs and ROS suggests that EPFRs may be involved in ROS generation. The correlation analysis indicated that the oxidative potential measured using the DTT method (OPDTT) could serve as an indicator of ROS generation. Finally, based on the relationship between OPDTT, EPFRs, and ROS, we propose that reducing the emission of transition metals, particularly Fe, represents an effective control measure for mitigating PM toxicity near highways.
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Affiliation(s)
- Xinji Zhang
- Department of Environmental Engineering, Xiamen University of Technology, Xiamen, 361024, China
| | - Yidan Wang
- Department of Environmental Engineering, Xiamen University of Technology, Xiamen, 361024, China
| | - Kaixing Yao
- Department of Environmental Engineering, Xiamen University of Technology, Xiamen, 361024, China
| | - Han Zheng
- Department of Environmental Engineering, Xiamen University of Technology, Xiamen, 361024, China
| | - Huibin Guo
- Department of Environmental Engineering, Xiamen University of Technology, Xiamen, 361024, China.
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5
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Hasan F, Potter PM, Al-Abed SR, Matheson J, Lomnicki SM. Investigating environmentally persistent free radicals (EPFRs) emissions of 3D printing process. CHEMICAL ENGINEERING JOURNAL (LAUSANNE, SWITZERLAND : 1996) 2024; 480:1-6. [PMID: 38510278 PMCID: PMC10953813 DOI: 10.1016/j.cej.2023.148158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
In recent years, the emission of particles and gaseous pollutants from 3D printing has attracted much attention due to potential health risks. This study investigated the generation of environmentally persistent free radicals (EPFRs, organic free radicals stabilized on or inside particles) in total particulate matter (TPM) released during the 3D printing process. Commercially available 3D printer filaments, made of acrylonitrile-butadiene-styrene (ABS) in two different colors and metal content, ABS-blue (19.66 μg/g Cu) and ABS-black (3.69 μg/g Fe), were used for printing. We hypothesized that the metal content/composition of the filaments contributes not only to the type and number of EPFRs in TPM emissions, but also impacts the overall yield of TPM emissions. TPM emissions during printing with ABS-blue (11.28 μg/g of printed material) were higher than with ABS-black (7.29 μg/g). Electron paramagnetic resonance (EPR) spectroscopy, employed to measure EPFRs in TPM emissions of both filaments, revealed higher EPFR concentrations in ABS-blue TPM (6.23 × 1017 spins/g) than in ABS-black TPM (9.72 × 1016 spins/g). The presence of copper in the ABS-blue contributed to the formation of mostly oxygen-centered EPFR species with a g-factor of ~2.0041 and a lifetime of 98 days. The ABS-black EPFR signal had a lower g-factor of ~2.0011, reflecting the formation of superoxide radicals during the printing process, which were shown to have an "estimated tentative" lifetime of 26 days. Both radical species (EPFRs and superoxides) translate to a potential health risk through inhalation of emitted particles.
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Affiliation(s)
- Farhana Hasan
- Department of Environmental Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Phillip M. Potter
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Environmental Research and Emergency Response, Cincinnati, OH 45268, USA
| | - Souhail R. Al-Abed
- U.S. Environmental Protection Agency, Office of Research and Development, Center for Environmental Research and Emergency Response, Cincinnati, OH 45268, USA
| | - Joanna Matheson
- U.S. Consumer Product and Safety Commission, Health Sciences Directorate, Rockville, MD 20850, USA
| | - Slawomir M. Lomnicki
- Department of Environmental Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
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6
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Yi JF, Lin ZZ, Li X, Zhou YQ, Guo Y. A short review on environmental distribution and toxicity of the environmentally persistent free radicals. CHEMOSPHERE 2023; 340:139922. [PMID: 37611755 DOI: 10.1016/j.chemosphere.2023.139922] [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: 02/14/2023] [Revised: 06/09/2023] [Accepted: 08/21/2023] [Indexed: 08/25/2023]
Abstract
Environmentally Persistent Free Radicals (EPFRs) are usually generated by the electron transfer of a certain radical precursor on the surface of a carrier. They are characterized with high activity, wide migration range, and relatively long half-life period. In this review, we summarized the literature on EPFRs published since 2010, including their environmental occurrence and potential cytotoxicity and biotoxicity. The EPFRs in the atmosphere are the most abundant in the environment, mainly generated from the combustion of raw materials or biochar, and the C-center types (quinones, semiquinones radicals, etc.) may exist for a relatively long time. These EPFRs can transform into other substances (such as reactive oxygen species, ROS) under the influence of environmental factors, and partly enter soil and water by wet and dry deposition of particulate matter, which may promote the generation of EPFRs in those media. The wide distribution of EPFRs in the environment may lead to their exposure to biota including humans, resulting in cytotoxicity and biotoxicity. The EPFRs can influence the normal redox process of the biota, and generate a large number of free radicals like ROS. Exposure to EPFRs may change the expression of gene and activity of metabolic enzymes, and damage the cells, as well as some organs such as the lung, trachea, and heart. However, due to the difficulty in sample extraction, identification, and quantification of the specific EPFR individuals, the toxicity and exposure evaluation of biota are still limited which merits study in the future.
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Affiliation(s)
- Jing-Feng Yi
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 511443, China
| | - Ze-Zhao Lin
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 511443, China
| | - Xing Li
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 511443, China
| | - Yue-Qiao Zhou
- Department of Department of Medical Oncology, Qionghai People's Hospital, Qionghai, 571499, China.
| | - Ying Guo
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 511443, China.
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7
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Pan W, Chang J, He S, Liu X, Fu J, Zhang A. Machine learning strategy on activation energy of environmental heterogeneous reactions and its application to atmospheric formation of typical montmorillonite-bound phenoxy radicals. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 895:165117. [PMID: 37364832 DOI: 10.1016/j.scitotenv.2023.165117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/15/2023] [Accepted: 06/23/2023] [Indexed: 06/28/2023]
Abstract
Heterogeneous transformation of organic pollutants into more toxic chemicals poses substantial health risks to humans. Activation energy is an important indicator that help us to understand transformation efficacy of environmental interfacial reactions. However, the determination of activation energies for large numbers of pollutants using either the experimental or high-accuracy theoretical methods is expensive and time-consuming. Alternatively, the machine learning (ML) method shows the strength in predictive performance. In this study, using the formation of a typical montmorillonite-bound phenoxy radical as an example, a generalized ML framework RAPID was proposed for activation energy prediction of environmental interfacial reactions. Accordingly, an explainable ML model was developed to predict the activation energy via easily accessible properties of the cations and organics. The model developed by decision tree (DT) performed best with the lowest root-mean-squared error (RMSE = 0.22) and the highest coefficient of determination values (R2 score = 0.93), the underlying logic of which was well understood by combining model visualization and SHapley Additive exPlanations (SHAP) analysis. The performance and interpretability of the established model suggest that activation energies can be predicted by the well-designed ML strategy, and this would allow us to predict more heterogeneous transformation reactions in the environmental field.
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Affiliation(s)
- Wenxiao Pan
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China
| | - Jiamin Chang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Shuming He
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310012, PR China
| | - Xian Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, PR China.
| | - Jianjie Fu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310012, PR China
| | - Aiqian Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, PR China; School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310012, PR China.
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8
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Sarmiento DJ, Majestic BJ. Formation of Environmentally Persistent Free Radicals from the Irradiation of Polycyclic Aromatic Hydrocarbons. J Phys Chem A 2023. [PMID: 37316958 DOI: 10.1021/acs.jpca.3c01405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) provide a complex matrix for environmentally persistent free radicals (EPFRs) to stabilize in particulate matter, allowing them to be transported over long distances in the atmosphere while participating in light-driven reactions and causing various cardiopulmonary diseases. In this study, four PAHs ranging from three to five rings (anthracene, phenanthrene, pyrene, and benzo[e]pyrene) were investigated for EPFR formation upon photochemical and aqueous-phase aging. Through electron paramagnetic resonance (EPR) spectroscopy, it was found that approximately 1015 to 1016 spins g-1 of EPFRs were formed from the PAH upon aging. EPR analysis also revealed that carbon-centered and monooxygen-centered radicals were predominantly formed by irradiation. However, oxidation and fused-ring matrices have added complexity to the chemical environment of these carbon-centered radicals, as observed by their g-values. This study showed that atmospheric aging results not only in the transformation of PAH-derived EPFR but also in an increase in EPFR concentrations of up to 1017 spins g-1. Therefore, because of their stability and photosensitivity, PAH-derived EPFRs have a major impact on the environment.
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Affiliation(s)
- Desiree J Sarmiento
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Brian J Majestic
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
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9
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Ainur D, Chen Q, Sha T, Zarak M, Dong Z, Guo W, Zhang Z, Dina K, An T. Outdoor Health Risk of Atmospheric Particulate Matter at Night in Xi'an, Northwestern China. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023. [PMID: 37311058 DOI: 10.1021/acs.est.3c02670] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The deterioration of air quality via anthropogenic activities during the night period has been deemed a serious concern among the scientific community. Thereby, we explored the outdoor particulate matter (PM) concentration and the contributions from various sources during the day and night in winter and spring 2021 in a megacity, northwestern China. The results revealed that the changes in chemical compositions of PM and sources (motor vehicles, industrial emissions, coal combustion) at night lead to substantial PM toxicity, oxidative potential (OP), and OP/PM per unit mass, indicating high oxidative toxicity and exposure risk at nighttime. Furthermore, higher environmentally persistent free radical (EPFR) concentration and its significant correlation with OP were observed, suggesting that EPFRs cause reactive oxygen species (ROS) formation. Moreover, the noncarcinogenic and carcinogenic risks were systematically explained and spatialized to children and adults, highlighting intensified hotspots to epidemiological researchers. This better understanding of day-night-based PM formation pathways and their hazardous impact will assist to guide measures to diminish the toxicity of PM and reduce the disease led by air pollution.
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Affiliation(s)
- Dyussenova Ainur
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Qingcai Chen
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Tong Sha
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Mahmood Zarak
- UNSW Centre for Transformational Environmental Technologies, Yixing 214200, China
| | - Zipeng Dong
- Shaanxi Academy of Meteorological Sciences, Xi'an 710014, China
| | - Wei Guo
- Shaanxi Academy of Environmental Sciences, Xi'an 710061, China
| | - Zimeng Zhang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Kukybayeva Dina
- Faculty of Tourism and Languages, Yessenov University, Aktau 130000, Kazakhstan
| | - Taicheng An
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
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10
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Xu Y, Lu X, Su G, Chen X, Meng J, Li Q, Wang C, Shi B. Scientific and regulatory challenges of environmentally persistent free radicals: From formation theory to risk prevention strategies. JOURNAL OF HAZARDOUS MATERIALS 2023; 456:131674. [PMID: 37236112 DOI: 10.1016/j.jhazmat.2023.131674] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 05/18/2023] [Accepted: 05/20/2023] [Indexed: 05/28/2023]
Abstract
EPFRs (Environmentally Persistent Free Radicals) are a class of pollutants that have been identified as potential environmental contaminants due to their persistence and ability to generate reactive oxygen species (ROS) that can cause oxidative stress in living organisms. However, no study has comprehensively summarized the production conditions, influencing factors and toxic mechanisms of EPFRs, impeding exposure toxicity assessments and risk prevention strategies. To bridge the gap between theoretical research and practical application, a thorough literature review to summarize the formation, environmental effects, and biotoxicity of EPFRs are conducted. A total of 470 relevant papers were screened in Web of Science Core collection databases. The transfer of electrons between interfaces and the cleavage of covalent bonds of persistent organic pollutants is crucial to the generation of EPFRs, which is induced by external sources of energy, including thermal energy, light energy, transition metal ions, and others. In the thermal system, the stable covalent bond of organic matter can be destroyed by heat energy at low temperature to form EPFRs, while the formed EPFRs can be destroyed at high temperature. Light can also accelerate the production of free radicals and promote the degradation of organic matter. The persistence and stability of EPFRs are synergistically influenced by individual environmental factors such as environmental humidity, oxygen content, organic matter content, and environmental pH. Studying the formation mechanism of EPFRs and their biotoxicity is essential for fully understanding the hazards posed by these emerging environmental contaminants.
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Affiliation(s)
- Yulin Xu
- School of Municipal and Environmental Engineering, Shenyang Jianzhu University, Shenyang 110168, China; Key Laboratory of Environmental Nanotechnology and Health Effects Research, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xiaofei Lu
- School of Municipal and Environmental Engineering, Shenyang Jianzhu University, Shenyang 110168, China
| | - Guijin Su
- Key Laboratory of Environmental Nanotechnology and Health Effects Research, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xing Chen
- School of Municipal and Environmental Engineering, Shenyang Jianzhu University, Shenyang 110168, China; Key Laboratory of Environmental Nanotechnology and Health Effects Research, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jing Meng
- Key Laboratory of Environmental Nanotechnology and Health Effects Research, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qianqian Li
- Key Laboratory of Environmental Nanotechnology and Health Effects Research, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chenxi Wang
- School of Municipal and Environmental Engineering, Shenyang Jianzhu University, Shenyang 110168, China; Key Laboratory of Environmental Nanotechnology and Health Effects Research, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Bin Shi
- Key Laboratory of Environmental Nanotechnology and Health Effects Research, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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11
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Zhao J, Shi L, Shi J, Li H, Lang D, Wei Z, Li S, Pan B. Distribution of environmentally persistent free radicals in size-segregated PMs emitted from residential biomass fuel combustion. JOURNAL OF HAZARDOUS MATERIALS 2023; 449:130956. [PMID: 36812726 DOI: 10.1016/j.jhazmat.2023.130956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/22/2023] [Accepted: 02/04/2023] [Indexed: 06/18/2023]
Abstract
Environmentally persistent free radicals (EPFRs) are considered as an emerging pollutant due to their potential environmental risks, but the distribution characteristics of particulate matters (PMs)-EPFRs from residential combustion source are poorly understood. In this study, biomass (corn straw, rice straw, pine and jujube wood) combustion was studied in lab-controlled experiments. More than 80% of PM-EPFRs were distributed in PMs with aerodynamic diameter (dae) ≤ 2.1 µm, and their concentration in fine PMs was about 10 times that in coarse PM (2.1 µm ≤ dae ≤ 10 µm). The detected EPFRs were carbon-centered free radicals adjacent to oxygen atoms or a mixture of oxygen- and carbon-centered radicals. The concentrations of EPFRs in coarse and fine PMs were positively correlated with char-EC, but the EPFRs in fine PMs exhibited a negative correlation with soot-EC (p < 0.05). The increase of PM-EPFRs signals with the increased dilution ratio during pine wood combustion was more significant than that from rice straw, which may be resulted from the interactions between the condensable volatiles and the transition metals. Our study provides useful information for better understanding the formation of combustion-derived PM-EPFRs, and will be instructive for its purposeful emissions control.
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Affiliation(s)
- Jinfeng Zhao
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming 650500, Yunnan, China
| | - Lin Shi
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming 650500, Yunnan, China; Shandong Provincial Key Laboratory of Water and Soil Conservation and Environmental Protection, College of Resources and Environment, Linyi University, Linyi 276005, China
| | - Jianwu Shi
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming 650500, Yunnan, China
| | - Hao Li
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming 650500, Yunnan, China
| | - Di Lang
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming 650500, Yunnan, China
| | - Zhuo Wei
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming 650500, Yunnan, China
| | - Shunling Li
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming 650500, Yunnan, China
| | - Bo Pan
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming 650500, Yunnan, China.
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12
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Liu X, Liu G, Liu S, Qin L, Lin B, Wang M, Yang L, Zheng M. Free radical mechanism of toxic organic compound formations from o-chlorophenol. JOURNAL OF HAZARDOUS MATERIALS 2023; 443:130367. [PMID: 36444078 DOI: 10.1016/j.jhazmat.2022.130367] [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: 07/13/2022] [Revised: 11/07/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
Organic free radical intermediates are pivotal to our understanding of toxic chemicals formation from chlorophenols that widely exist in thermal processes. However, in most cases, multiple free radical intermediates exist and produce complex spectra that are hard to deconvolute. Identification of free radical intermediates is the current difficulty for detailed formation mechanisms of toxic products from chlorophenols. In this study, a universal bottom-up method was developed to identify the organic free radical intermediates. Candidate organic free radicals were firstly speculated according to the critical parameters obtained from experimental electron paramagnetic resonance (EPR) spectra and the calculated bond dissociation energies of precursors. Their theoretical spectra were then used retrospectively to justify the accordance with the experimental EPR spectra. Identification of the organic free radicals provides straightforward evidence for the formation pathways of pollutants from chlorophenol. Internal factors influencing formation of radical intermediates and the toxic products were also studied, including the ortho effect of the precursor, spin densities of the organic free radical intermediates, and steric hindrance effects of the molecular intermediates. In combination of the experimental results and theoretical calculations, detailed formation mechanisms of toxic pollutants intermediating by organic free radicals from thermal oxidation of chlorophenol were strongly evidenced.
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Affiliation(s)
- Xiaoyun Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guorui Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; School of the Environment, Hangzhou Institute for Advanced Study, University of the Chinese Academy of Sciences, Hangzhou 310024, China
| | - Shuting Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Linjun Qin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bingcheng Lin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; School of the Environment, Hangzhou Institute for Advanced Study, University of the Chinese Academy of Sciences, Hangzhou 310024, China
| | - Mingxuan Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lili Yang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China.
| | - Minghui Zheng
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; School of the Environment, Hangzhou Institute for Advanced Study, University of the Chinese Academy of Sciences, Hangzhou 310024, China
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13
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Yang J, Fang L, Li Z, Meng G, Jia Y, Jiang Y, Lian J, Gan X. Insights into the formation of environmentally persistent free radicals during photocatalytic degradation processes of ceftriaxone sodium by ZnO/ZnIn 2S 4. CHEMOSPHERE 2023; 314:137618. [PMID: 36563725 DOI: 10.1016/j.chemosphere.2022.137618] [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: 08/10/2022] [Revised: 12/03/2022] [Accepted: 12/18/2022] [Indexed: 06/17/2023]
Abstract
At present, the researches on photocatalysis were mainly focused on the design, improvement and development of catalysts, and less attention was paid to the existing characteristics of environmentally persistent free radicals (EPFRs) during the process of photocatalytic oxidation. In this study, A flower-like Z-type heterojunction ZnO/ZnIn2S4 (ZnO/ZIS) and typical antibiotic ceftriaxone sodium (CS) were taken as study objects, concentrating on the generation characteristics of EPFRs during the degradation of CS by ZnO/ZIS, and clarifying the degradation mechanism of CS in which EPFRs participated. The results showed that the degradation efficiency of 10 mg/L CS by 0.40 g/L ZnO/ZIS reached 85.3% in 150 min under the irradiation of 500 W xenon lamp. It was clear that ·O2- and h+ play major roles in CS degradation by ZnO/ZIS under visible light, and ·OH plays an auxiliary role. Furthermore, the formation mechanism of EPFRs during photocatalytic degradation processes of CS by ZnO/ZIS were first investigated thoroughly via experimental analysis and density functional theory (DFT) calculations. The concentration level of EPFRs centered on oxygen atoms is 1011 spin/mm3, which were generated in the process of degradation of CS by ZnO/ZIS under visible light. The production of EPFRs chiefly includes two procedures: chemical adsorption and transfer of electrons. The adsorption energy of precursor P8 on ZnIn2S4 side is -1.91 eV, the electrons transferred from precursor P8 and P11 to ZnO/ZnIn2S4 heterojunction. Surprisingly, EPFRs have little negative effects on the degradation process of CS by ZnO/ZIS. The study was not only a key field in the development of photocatalysis technology, but also a new way to study the removal mechanism of antibiotics.
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Affiliation(s)
- Jianhua Yang
- Anhui University of Technology, School of Energy and Environment, Maanshan, 243002, Anhui, China; State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing, 210023, China; Engineering Research Center of Biofilm Water Purification and Utilization Technology of Ministry of Education, Maanshan, 243002, Anhui, China
| | - Lu Fang
- Anhui University of Technology, School of Energy and Environment, Maanshan, 243002, Anhui, China
| | - Zhengkui Li
- State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing, 210023, China; School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Guanhua Meng
- Anhui University of Technology, School of Energy and Environment, Maanshan, 243002, Anhui, China; Engineering Research Center of Biofilm Water Purification and Utilization Technology of Ministry of Education, Maanshan, 243002, Anhui, China
| | - Yong Jia
- Anhui University of Technology, School of Energy and Environment, Maanshan, 243002, Anhui, China; Engineering Research Center of Biofilm Water Purification and Utilization Technology of Ministry of Education, Maanshan, 243002, Anhui, China
| | - Yongbin Jiang
- Anhui University of Technology, School of Energy and Environment, Maanshan, 243002, Anhui, China; Engineering Research Center of Biofilm Water Purification and Utilization Technology of Ministry of Education, Maanshan, 243002, Anhui, China
| | - Jianjun Lian
- Anhui University of Technology, School of Energy and Environment, Maanshan, 243002, Anhui, China; Engineering Research Center of Biofilm Water Purification and Utilization Technology of Ministry of Education, Maanshan, 243002, Anhui, China
| | - Xinhong Gan
- State Environmental Protection Key Laboratory of Soil Environmental Management and Pollution Control, Nanjing Institute of Environmental Science, Ministry of Ecology and Environment (MEE) of China, Nanjing, 210042, China.
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14
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Li H, Chen Q, Wang C, Wang R, Sha T, Yang X, Ainur D. Pollution characteristics of environmental persistent free radicals (EPFRs) and their contribution to oxidation potential in road dust in a large city in northwest China. JOURNAL OF HAZARDOUS MATERIALS 2023; 442:130087. [PMID: 36206715 DOI: 10.1016/j.jhazmat.2022.130087] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 09/22/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
Environmental persistent free radicals (EPFRs) are new environmental health risk substances in the atmosphere, and their oxidative toxicity (OT) has not been strongly confirmed. In this study, the fugitive characteristics of EPFRs in road dust in a metropolitan city located in northwest China, and their potential oxidative toxicity were investigated. The results showed that the road dust contains Carbon-centered EPFRs with the mean mass concentration of (6.6 ± 5.0) × 1017 spins/g. EPFRs in road dust are degradable and have a half-life of 4.5 years. The water insoluble (WIS) components contribute 71% to the oxidative toxicity of road dust and show a rapid toxicity generation process, while the oxidative toxicity generation rate of water-soluble dust is more stable. Based on the positive matrix factorization (PMF) model, the contribution of EPFRs-dominated factors to Total-OT and WIS-OT is 17.3% and 33.3%, respectively. The PMF model results indicated that different types of EPFRs contributed differently to the oxidative toxicity of road dust and Carbon-centered EPFRs are more likely to participate in reactive oxygen species generation. Our results highlight that the EPFRs are an important contributor to the oxidative toxicity of atmospheric particulate matter, and their oxidative toxicity is dependent on the types of free radicals. It also provides an important insight into the influence of other potentially toxic substances on the oxidative toxicity of atmospheric PM.
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Affiliation(s)
- Hao Li
- School of Environmental Science and Engineering., Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Qingcai Chen
- School of Environmental Science and Engineering., Shaanxi University of Science and Technology, Xi'an 710021, China.
| | - Chao Wang
- Beijing China Railway Construction Technology Co., LTD, Beijing 100040, China
| | - Ruihe Wang
- Beijing China Railway Construction Technology Co., LTD, Beijing 100040, China
| | - Tong Sha
- School of Environmental Science and Engineering., Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Xiqi Yang
- School of Environmental Science and Engineering., Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Dyussenova Ainur
- School of Environmental Science and Engineering., Shaanxi University of Science and Technology, Xi'an 710021, China
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15
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Guo H, Wang Y, Yao K, Zheng H, Zhang X, Li R, Wang N, Fu H. The overlooked formation of environmentally persistent free radicals on particulate matter collected from biomass burning under light irradiation. ENVIRONMENT INTERNATIONAL 2023; 171:107668. [PMID: 36459822 DOI: 10.1016/j.envint.2022.107668] [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: 09/22/2022] [Revised: 11/17/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND The illumination process may be an important contributor to environmentally persistent free radicals (EPFRs) in atmospheric particles, but the ability of light to generate EPFRs in combustion products remains unclear. OBJECTIVE This paper studies the characteristics and formation mechanism of EPFRs in combustion particles after photoexcitation. METHOD The secondary photochemical processes and the generation and decay capability of EPFRs in size-resolved (<10 µm) biomass combustion particles were analysed by electron paramagnetic resonance (EPR) spectroscopy. RESULT Our results indicated that secondary EPFRs can be generated after illumination and the produced EPFRs have a lifetime of approximately 1 day. The content of secondary EPFRs after light exposure increased by 20 %-30 % compared to that of the original EPFRs. Through the analysis of components of different polarities, it was found that non-extractable substances were the main contributors to secondary EPFRs (75 %), followed by extractable organics. This study showed that metal species and quinones are important precursors for the formation of secondary EPFRs from non-extractable and extractable PM components, respectively. We found that O2 molecules are an important factor for the formation of secondary EPFRs from organic substances without oxygen functional groups. CONCLUSIONS This study presents information about the effects of light and O2 on the generation of EPFRs, and the unstable nature of secondary EPFRs has important implications for assessing the health risks of atmospheric particles.
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Affiliation(s)
- Huibin Guo
- Department of Environmental Engineering, Xiamen University of Technology, Xiamen 361024, China.
| | - Yidan Wang
- Department of Environmental Engineering, Xiamen University of Technology, Xiamen 361024, China
| | - Kaixing Yao
- Department of Environmental Engineering, Xiamen University of Technology, Xiamen 361024, China
| | - Han Zheng
- Department of Environmental Engineering, Xiamen University of Technology, Xiamen 361024, China
| | - Xinji Zhang
- Department of Environmental Engineering, Xiamen University of Technology, Xiamen 361024, China
| | - Rui Li
- Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing 100084, China
| | - Ning Wang
- Department of Environmental and Material Engineering, Yantai University, Yantai 264005, China
| | - Haiyan Fu
- Department of Environmental Engineering, Xiamen University of Technology, Xiamen 361024, China
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16
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Lin H, Chen Q, Wang M, Chang T. Oxidation potential and coupling effects of the fractionated components in airborne fine particulate matter. ENVIRONMENTAL RESEARCH 2022; 213:113652. [PMID: 35700767 DOI: 10.1016/j.envres.2022.113652] [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] [Received: 03/24/2022] [Revised: 06/04/2022] [Accepted: 06/08/2022] [Indexed: 06/15/2023]
Abstract
Fine particulate matter (PM2.5) can induce the generation of reactive oxygen species (ROS) and damage human tissues. Fully understanding the generation mechanism of oxidative toxicity of PM is challenging due to the extremely complex composition. Classification methods may be helpful in understanding the ROS production mechanisms of complex PM. This study used a solvent extraction and solid phase extraction methods to separate five different components from PM2.5 includes non-extractable components that have rarely been studied before, and discussed the coupling effect and heterogeneous characteristics of oxidation activity they produced. It is found that the water-soluble component contribute about half of the PM oxidation activity, and metal ions probably contribute most of the oxidation activity. Experimental results show that oxygen molecules is the main precursor of ROS production, which depends on whether the aerosol component has catalytic conversion ability. After mixing humic-like substance (HULIS) and hydrophilic water-soluble (HP-WSM) PM, the oxidation activity increased, it is most likely to be a synergistic effect between HULIS and metal ions is dominant, but limited contribution to oxidation activity. It turns out that the non-extractable and water-insoluble components have higher oxidation activity than the water-soluble components, and the two components exhibited a more durable ability to produce 1O2. The reaction of soluble components to produce ROS is homogeneous, but it is obviously heterogeneous for these insoluble components. This study suggests that future attention should be paid to the oxidative toxicity of the non-extractable component, and that single PM component or compound cannot simply be studied independently.
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Affiliation(s)
- Hao Lin
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China
| | - Qingcai Chen
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China.
| | - Mamin Wang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China
| | - Tian Chang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China
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17
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Ainur D, Chen Q, Wang Y, Li H, Lin H, Ma X, Xu X. Pollution characteristics and sources of environmentally persistent free radicals and oxidation potential in fine particulate matter related to city lockdown (CLD) in Xi'an, China. ENVIRONMENTAL RESEARCH 2022; 210:112899. [PMID: 35176313 PMCID: PMC9558116 DOI: 10.1016/j.envres.2022.112899] [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: 11/22/2021] [Revised: 12/29/2021] [Accepted: 02/03/2022] [Indexed: 05/17/2023]
Abstract
The impact of COVID-19 control on air quality have been prevalent for the past two years, however few studies have explored the toxicity of atmospheric particulate matter during the epidemic control. Therefore, this research highlights the characteristics and sources of oxidative potential (OP) and the new health risk substances environmentally persistent free radicals (EPFRs) in comparison to city lockdown (CLD) with early days of 2019-2020. Daily particulate matter (PM2.5) samples were collected from January 14 to February 3, 2020, with the same period during 2019 in Xi'an city. The results indicated that the average concentration of PM2.5 decreased by 48% during CLD. Concentrations of other air pollutants and components, such as PM10, NO2, SO2, WSIs, OC and EC were also decreased by 22%, 19%, 2%, 17%, 6%, and 4% respectively during the CLD, compared to the same period in 2019. Whereas only O3 increased by 30% during CLD. The concentrations of EPFRs in PM2.5 was considerably lower than in 2019, which decreased by 12% during CLD. However, the OP level was increased slightly during CLD. Moreover, both EPFRs/PM and DTTv/PM did not decrease or even increase significantly, manifesting that the toxicity of particulate matter has not been reduced by more gains during the CLD. Based on PMF analysis, during the epidemic period, the contribution of traffic emission is significantly reduced, while EPFRs and DTTv increased, which consist of significant O3 and secondary aerosols. This research leads to able future research on human health effect of EPFRs and oxidative potential and can be also used to formulate the majors to control EPFRs and OP emissions, suggest the need for further studies on the secondary processing of EPFRs and OP during the lockdown period in Xi'an. .The COVID-19 lockdown had a significant impact on both social and economic aspects. The city lockdown, however, had a positive impact on the environment and improved air quality, however, no significant health benefits were observed in Xi'an, China.
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Affiliation(s)
- Dyussenova Ainur
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China
| | - Qingcai Chen
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China.
| | - Yuqin Wang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China
| | - Hao Li
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China
| | - Hao Lin
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China
| | - Xuying Ma
- College of Geomatics, Xi'an University of Science and Technology, Xi'an, 710054, China
| | - Xin Xu
- Xi'an Institute for Innovative Earth Environment Research, Xi'an, 710061, China
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18
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Characteristics of Environmentally Persistent Free Radicals in PM2.5 and the Influence of Air Pollutants in Shihezi, Northwestern China. TOXICS 2022; 10:toxics10070341. [PMID: 35878247 PMCID: PMC9321939 DOI: 10.3390/toxics10070341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 06/15/2022] [Accepted: 06/18/2022] [Indexed: 11/17/2022]
Abstract
Environmentally persistent free radicals (EPFRs) are a kind of hazardous substance that exist stably in the atmosphere for a long time. EPFRs combined with fine particulate matter (PM2.5) can enter the human respiratory tract through respiration, causing oxidative stress and DNA damage, and they are also closely related to lung cancer. In this study, the inhalation risk for EPFRs in PM2.5 and factors influencing this risk were assessed using the equivalent number of cigarette tar EPFRs. The daily inhalation exposure for EPFRs in PM2.5 was estimated to be equivalent to 0.66–8.40 cigarette tar EPFRs per day. The concentration level and species characteristics were investigated using electron paramagnetic resonance spectroscopy. The concentration of EPFRs in the study ranged from 1.353–4.653 × 1013 spins/g, and the types of EPFRs were mainly oxygen- or carbon-centered semiquinone-type radicals. Our study showed that there is a strong correlation between the concentrations of EPFRs and conventional pollutants, except for sulfur dioxide. The major factors influencing EPFR concentration in the atmosphere were temperature and wind speed; the higher the temperature and wind speed, the lower the concentration of EPFRs. The findings of this study provide an important basis for further research on the formation mechanism and health effects of EPFRs.
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19
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Zhu P, Zhang W, Feng F, Qin L, Ji W, Li D, Liang R, Zhang Y, Wang Y, Li M, Wu W, Jin Y, Duan G. Role of angiotensin-converting enzyme 2 in fine particulate matter-induced acute lung injury. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 825:153964. [PMID: 35182631 DOI: 10.1016/j.scitotenv.2022.153964] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 02/14/2022] [Accepted: 02/14/2022] [Indexed: 06/14/2023]
Abstract
Fine particulate matter (PM2.5) pollution poses significant health concerns worldwide and can cause respiratory diseases. However, how it causes health problems is still poorly understood. Angiotensin-converting enzyme (ACE)2 is a terminal carboxypeptidase implicated in the functions of renin-angiotensin system (RAS) and plays a crucial role in the control of lung inflammation. To investigate whether ACE2 functions in PM2.5-induced lung inflammation, wild-type (WT) C57BL/6J mice and ACE2 knock-out (KO) mice were intratracheally instilled with PBS or PM2.5 suspension for 3 consecutive days, respectively. The concentrations of cytokines in bronchoalveolar lavage fluid (BALF) were determined by ELISA. The expression of ACE2 and ACE and activation of inflammatory signaling pathways in lung tissues were evaluated by immunofluorescence staining and Western blotting. We found that PM2.5 exposure increased ACE2 expression. Loss of ACE2 significantly elevated the levels of total proteins, total cells, and the concentrations of MCP-1, IL-1β in BALF after PM2.5 challenge. Additionally, loss of ACE2 enhanced lung pathologies, airway resistance, and inflammatory signaling activation. Collectively, loss of ACE2 exacerbates PM2.5-induced acute lung injury in mice.
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Affiliation(s)
- Peiyu Zhu
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China; Henan Key Laboratory of Molecular Medicine, Zhengzhou University, Zhengzhou 450001, China
| | - Wenfen Zhang
- Center of Advanced Analysis and Computational Science, Key Laboratory of Molecular Sensing and Harmful Substances Detection Technology, Zhengzhou University, Zhengzhou 450001, China
| | - Feifei Feng
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China
| | - Luwei Qin
- Henan Province Center for Disease Control and Prevention, Zhengzhou 450016, China
| | - Wangquan Ji
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China
| | - Dong Li
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China
| | - Ruonan Liang
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China
| | - Yu Zhang
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China
| | - Yuexia Wang
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China
| | - Mengyuan Li
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China
| | - Weidong Wu
- School of Public Health, Xinxiang Medical University, Xinxiang 453003, Henan, China
| | - Yuefei Jin
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China.
| | - Guangcai Duan
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China; Henan Key Laboratory of Molecular Medicine, Zhengzhou University, Zhengzhou 450001, China.
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20
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Zhao J, Shen G, Shi L, Li H, Lang D, Zhang L, Pan B, Tao S. Real-World Emission Characteristics of Environmentally Persistent Free Radicals in PM 2.5 from Residential Solid Fuel Combustion. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:3997-4004. [PMID: 35262334 DOI: 10.1021/acs.est.1c08449] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Environmentally persistent free radicals (EPFRs) can induce reactive oxygen species, causing adverse health impacts, and residential fuel (biomass and coal) combustion is believed to be an important emission source for EPFRs; however, the residential emission characteristics of EPFRs are rarely studied in the real world. Here, we conducted a field campaign evaluating the presence and characteristics of EPFRs generated from residential biomass and coal burning in rural China. The emission factors (EFs) of EPFRs (with units of 1020 spins·kg-1) in PM2.5 from the combustion of crop residues (3.97 ± 0.47) were significantly higher than those from firewood (2.06 ± 0.19) and coal (2.13 ± 0.33) (p < 0.05). The EPFRs from residential solid fuel combustion were carbon-centered free radicals adjacent to oxygen atoms. The fuel type was a primary factor controlling EPFR discharge, explaining 68% of the variation in EPFR EFs. The emissions from biomass burning had higher EPFRs per particle than those from coal combustion. EPFRs had stronger relationships with carbonaceous components than with other incomplete combustion products. The EPFRs from biomass burning were mostly generated during the pyrolysis of fuels, while the EPFRs generated from coal combustion were mainly associated with refractory organic compounds. This study provides valuable information for evaluating the fates of EPFRs, promoting a better understanding of the health impacts of air pollution.
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Affiliation(s)
- Jinfeng Zhao
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, Yunnan 650500, China
| | - Guofeng Shen
- College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Lin Shi
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, Yunnan 650500, China
| | - Hao Li
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, Yunnan 650500, China
| | - Di Lang
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, Yunnan 650500, China
| | - Lu Zhang
- College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Bo Pan
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, Yunnan 650500, China
| | - Shu Tao
- College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
- College of Environmental Science and Technology, Southern University of Science and Technology, Shenzhen 518055, China
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21
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Li Z, Zhao H, Li X, Bekele TG. Characteristics and sources of environmentally persistent free radicals in PM 2.5 in Dalian, Northeast China: correlation with polycyclic aromatic hydrocarbons. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:24612-24622. [PMID: 34822091 DOI: 10.1007/s11356-021-17688-9] [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] [Received: 07/27/2021] [Accepted: 11/18/2021] [Indexed: 06/13/2023]
Abstract
Environmentally persistent free radicals (EPFRs) are an emerging class of environmental hazardous contaminants that extensively, stably exist in airborne particulate matter and pose harmful effects on human health. However, there was little research about the sources of EPFRs in actual atmospheric conditions. This study reported the occurrence, characteristics, and sources of EPFRs and polycyclic aromatic hydrocarbons (PAHs) in PM2.5 collected in Dalian, China. The concentrations of PM2.5-bound EPFRs ranged from 1.13 × 1013 to 8.97 × 1015 spins/m3 (mean value: 1.14 × 1015 spins/m3). Carbon-centered radicals and carbon-centered radicals with adjacent oxygen atoms were detected. The concentration of ∑PAHs ranged from 1.09 to 76.24 ng/m3, and PAHs with high molecular weight (HMW) were predominant species in PM2.5. Correlation of EPFRs with SO2, NO2, O3, and 12 kinds of PAHs indicated that both fuel (coal and biomass) combustion and photoreaction in atmosphere influenced the concentrations of EPFR. The positive matrix factorization (PMF) model results have shown that the primary sources contributed most of the EPFRs and those of secondary sources had a little proportion. Coal combustion (52.4%) was the primary contributor of EPFRs, followed by traffic emission (22.6%), industrial sources (9.6%), and secondary sources (9.2%) during the heating period, whereas industrial emission (39.2%) was the primary contributor, followed by coal combustion (38.1%), vehicular exhaust (23.5%), and secondary sources (9.6%) during the non-heating period. The finding of the present study provides an important evidence for further study on the formation mechanism of EPFRs in actual atmospheric to control the air pollution.
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Affiliation(s)
- Zhansheng Li
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian, 116023, China
| | - Hongxia Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian, 116023, China.
| | - Xintong Li
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian, 116023, China
| | - Tadiyose Girma Bekele
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Linggong Road 2, Dalian, 116023, China
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22
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Compositions, Sources, and Aging Processes of Aerosol Particles during Winter Hazes in an Inland Megacity of NW China. ATMOSPHERE 2022. [DOI: 10.3390/atmos13040521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
As one of the largest inland megacities in Northwest (NW) China, Xi’an has been facing serious regional haze frequently, especially during winter. The composition of aerosols in Xi’an is highly complex due to its unique basinal topography and unique meteorological conditions. In this study, we characterized the morphology, size, and composition of individual aerosol particles collected during regional haze events at an urban site in Xi’an using Transmission Electron Microscopy (TEM) coupled with Energy-Dispersive X-ray Spectrometry (EDX). Six types of particles were identified based on their morphology and chemical composition, including organic (41.88%), sulfate (32.36%), soot (8.33%), mineral (7.91%), K-rich (5.13%), and fly ash particles (4.49%). These results demonstrate that the organic particles made a larger contribution to haze formation than the secondary inorganic particles during the sampling period. Size distribution and dominance suggest that organic and sulfate particles exert major control on the variation trends of particle size in haze. The coating thickness of organic-cored particles was about 369 nm and that of sulfate-cored particles was about 322 nm, implying that the organic particles were more aged than the sulfate particles. The results presented in this study provide further insights into understanding haze particle formation.
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23
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Ye Y, Li Y, Wang J, Yuan S, Xu X, Zhang X, Zhou J, Wang B, Ma X. Generation of Environmentally Persistent Free Radicals on Metal-Organic Frameworks. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:3265-3275. [PMID: 35245423 DOI: 10.1021/acs.langmuir.1c03491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Environmentally persistent free radicals (EPFRs) have been recognized as one of the important emerging contaminants with biological toxicity, environmental persistence, and global mobility. Previous studies have identified the catalytic role of surface metal oxides in EPFRs formation and illustrated the metal-dependence of EPFRs by studying on various metal oxide nanoparticles and single crystals. However, there is still lack of an understanding on the formation of EPFRs from the point of view of metal sites. Various factors (e.g., crystalline phases and surface species) of metal oxides are regarded to contribute to the generation of EPFRs, which present profound difficulties for scientists to tease apart the impact of metal type. Herein, a laboratory investigation, in terms of the acidity and oxidation strength of metal cations, was conducted by selecting metal-variable isostructural metal-organic frameworks as material platforms. Specifically, we evaluated EPFRs generation on MIL-100(M) (M = Al, Cr, Fe) from chlorine-substituted phenol vapor and catechol under thermal conditions. It is found that high Lewis acidity of metal sites is crucial for capturing the above two phenolic precursors, activating the O-H bond and promoting EPFRs formation. Radical species with half-life as long as 70 days were generated on MIL-100 rich in 5-fold coordinated Al3+ sites. The unpaired electron spin density donation was further confirmed by using 27Al solid-state nuclear magnetic resonance spectroscopy. Despite their higher oxidation power than Al3+, the exposed Cr3+ and Fe3+ sites show undetectable catalytic activity for the formation of EPFRs, because of their insufficient Lewis acidity. Our results suggest that the surface species rather than Lewis acid sites may be a major contributor to the formation of EPFRs on metal oxides like Fe2O3.
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Affiliation(s)
- Yuqing Ye
- Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science, Ministry of Education, Advanced Technology Research Institute (Jinan), School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Yuan Li
- Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science, Ministry of Education, Advanced Technology Research Institute (Jinan), School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Jie Wang
- Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science, Ministry of Education, Advanced Technology Research Institute (Jinan), School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Shuai Yuan
- Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science, Ministry of Education, Advanced Technology Research Institute (Jinan), School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Xiaojun Xu
- Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science, Ministry of Education, Advanced Technology Research Institute (Jinan), School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Xinning Zhang
- Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science, Ministry of Education, Advanced Technology Research Institute (Jinan), School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Junwen Zhou
- Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science, Ministry of Education, Advanced Technology Research Institute (Jinan), School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Bo Wang
- Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science, Ministry of Education, Advanced Technology Research Institute (Jinan), School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Xiaojie Ma
- Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science, Ministry of Education, Advanced Technology Research Institute (Jinan), School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China
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24
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Guo C, Richmond-Bryant J. A critical review of environmentally persistent free radical (EPFR) solvent extraction methodology and retrieval efficiency. CHEMOSPHERE 2021; 284:131353. [PMID: 34225117 PMCID: PMC8487994 DOI: 10.1016/j.chemosphere.2021.131353] [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: 04/02/2021] [Revised: 06/14/2021] [Accepted: 06/26/2021] [Indexed: 05/16/2023]
Abstract
Long-lived environmentally persistent free radical (EPFR) exposures have been shown in toxicology studies to lead to respiratory and cardiovascular effects, which were thought to be due to the persistence of EPFR and their ability to produce reactive oxygen species. To characterize EPFR exposure and resulting health impacts, it is necessary to identify and systematize analysis protocols. Both direct measurement and solvent extraction methods have been applied to analyze environmental samples containing EPFR. The use of different protocols and solvents in EPFR analyses makes it difficult to compare results among studies. In this work, we reviewed EPFR studies that involved solvent extraction and carefully reported the details of the extraction methodology and retrieval recovery. EPFR recovery depends on the structure of the radical species and the solvent. For the limited number of studies available for review, the polar solvents had superior recovery in more studies. Radicals appeared to be more oxygen-centered following extraction for fly ash and particulate matter (PM) samples. Different solvent extraction methods to retrieve EPFR may produce molecular products during the extraction, thus potentially changing the sample toxicity. The number of studies reporting detailed methodologies is limited, and data in these studies were not consistently reported. Thus, inference about the solvent and protocol that leads to the highest EPFR extraction efficiency for certain types of radicals is not currently possible. Based on our review, we proposed reporting criteria to be included for future EPFR studies.
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Affiliation(s)
- Chuqi Guo
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, 27695, USA.
| | - Jennifer Richmond-Bryant
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, 27695, USA
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25
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Characteristics and Potential Inhalation Exposure Risks of Environmentally Persistent Free Radicals in Atmospheric Particulate Matter and Solid Fuel Combustion Particles in High Lung Cancer Incidence Area, China. ATMOSPHERE 2021. [DOI: 10.3390/atmos12111467] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Environmentally persistent free radicals (EPFRs) were previously considered an unrecognized composition of air pollutants and might help explain the long-standing medical mystery of why non-smokers develop tobacco-related diseases such as lung cancer. However, there is no investigated on EPFRs in Xuanwei rural areas, especially in high prevalence of lung cancer areas. In this study, we selected six types of coal and three types of biomass in Xuanwei, then conducted simulated combustion, and six group of atmospheric particulate matters (APMs) to explore the content and particle size distribution pattern of EPFRs and a new health risk assessment method to evaluate the risk of EPFRs in PM for adults and children. Our results show that the contribution of EPFRs for biomass combustion, coal combustion and APMs were mainly distributed in the size range of <1.1 μm, which accounted for 76.15 ± 4.14%, 74.85 ± 10.76%, and 75.23 ± 8.18% of PM3.3. The mean g factors and ΔHp-p indicated that the EPFRs were mainly oxygen-centered radicals in PM in Xuanwei. The results suggest that the health risk of EPFRs is significantly increased when the particle size distribution of EPFRs is taken into account, and coal combustion particulate matter (174.70 ± 37.86 cigarettes for an adult, 66.39 ± 14.39 cigarettes per person per year for a child) is more hazardous to humans than biomass combustion particulate matter (69.41 ± 4.83 cigarettes for an adult, 26.37 ± 1.84 cigarettes per person per year for), followed by APMs (102.88 ± 39.99 cigarettes for an adult, 39.10 ±15.20 cigarettes per person per year for) in PM3.3. Our results provides a new perspective and evidence for revealing the reason for the high incidence of lung cancer in Xuanwei, China.
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26
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Guo C, Hasan F, Lay D, Dela Cruz ALN, Ghimire A, Lomnicki SM. Phytosampling-a supplementary tool for particulate matter (PM) speciation characterization. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:39310-39321. [PMID: 33755885 PMCID: PMC8713460 DOI: 10.1007/s11356-021-13292-z] [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: 07/09/2020] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
Ambient air particulate matter (PM) and PM-associated environmentally persistent free radicals (EPFRs) have been documented to contribute to pollution-related health effects. Studies of ambient air PM potentially bear artifacts stemming from the collection methods. We have investigated the applicability of PM phytosampling (PHS) as a supplementary tool to a classic PM sampler in respect of achieving better PM chemical composition assessment (primarily organic fraction). Phytosampling is a static PM collection method relying on the particle entrapment by the plant's leaf through electrostatic forces and surface trichomes. We have investigated the differences in the EPFR and polycyclic aromatic hydrocarbon (PAH) speciation and concentration on ambient air PM for PHS and high-volume PM sampler (HVS). The advantages of PHS are easy particle recovery from the matrix, collection under natural environmental conditions, and the ability to apply a dense collection network to accurately represent spatial pollutant distribution. The experimental results show that the PHS can provide valuable speciation information, sometimes different from that observed for HVS. For PM collected by PHS, we detected the larger contribution of oxygen-centered EPFRs, different decay behavior, and more consistent PAH distribution between different PM sizes compared to the PM from HVS. These results indicate that the isolation of samples from the ambient during HVS sampling and exposure to high-volume airflow may alter the chemical composition of the samples, while the PHS method could provide details on the original speciation and concentration and be more representative of the PM surface. However, PHS cannot evaluate an absolute air concentration of PM, so it serves as an excellent supplementary tool to work in conjunction with the standard PM collection method.
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Affiliation(s)
- Chuqi Guo
- Department of Environmental Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Farhana Hasan
- Department of Environmental Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Dean Lay
- Department of Environmental Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Albert Leo N Dela Cruz
- Department of Environmental Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Ajit Ghimire
- Department of Environmental Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Slawo M Lomnicki
- Department of Environmental Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
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27
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Zhu J, Shang J, Zhu T. A new understanding of the microstructure of soot particles: The reduced graphene oxide-like skeleton and its visible-light driven formation of reactive oxygen species. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 270:116079. [PMID: 33234379 DOI: 10.1016/j.envpol.2020.116079] [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: 07/21/2020] [Revised: 10/28/2020] [Accepted: 11/12/2020] [Indexed: 06/11/2023]
Abstract
The mechanisms of soot's photochemistry are still unclear, especially, how the microstructure and composition of soot influence its photoactivity. In the current study, we started with the exploration of the microstructure of soot particles and gained new insights. The elemental-carbon fraction of soot (E-soot), considered the core component of soot and can reflect the intrinsic characteristics of soot, was extracted by organic solvents and characterized in terms of structure and chemical reactivity. The intrinsic structure of E-soot was found to be more analogous to reduced graphene oxide than to graphene, in terms of containing similar levels of defective sites such as oxygen-containing functional groups and environmentally persistent free radicals, as well as exhibiting similar optoelectronic performance. The generation of reactive oxygen species via an electron transfer pathway under visible light suggests that reduced graphene oxide-like E-soot can serve as a potential carbo-photocatalyst, which facilitates elucidating the mechanism of E-soot's role during soot's photochemical aging. Our study reveals the intrinsic structure of soot and its role in photo-triggered reactive oxygen species production, which is vital for atmospheric and health effects.
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Affiliation(s)
- Jiali Zhu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, 5 Yiheyuan Road, Beijing, 100871, PR China
| | - Jing Shang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, 5 Yiheyuan Road, Beijing, 100871, PR China.
| | - Tong Zhu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, 5 Yiheyuan Road, Beijing, 100871, PR China; Beijing Innovation Center for Engineering Science and Advanced Technology (BIC-ESAT), Peking University, 5 Yiheyuan Road, Beijing, 100871, PR China
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28
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Niu X, Wang Y, Ho SSH, Chuang HC, Sun J, Qu L, Wang G, Ho KF. Characterization of organic aerosols in PM 1 and their cytotoxicity in an urban roadside area in Hong Kong. CHEMOSPHERE 2021; 263:128239. [PMID: 33297186 DOI: 10.1016/j.chemosphere.2020.128239] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 08/18/2020] [Accepted: 08/31/2020] [Indexed: 06/12/2023]
Abstract
Organic compounds in fine particles play major roles in cardiopulmonary diseases. A study was conducted to determine the characteristics and cytotoxicity of organic aerosols (OA) in an urban roadside area in Hong Kong. Chemical components in nonrefractory submicron aerosol (NR-PM1) were observed using a Quadrupole Aerosol Chemical Speciation Monitor (Q-ACSM), and the chemical profile of organic compounds in NR-PM1 was examined with filter-based approach. Associations between cytotoxicity and organic sources and compositions were evaluated. NR-PM1 contributed to 84% of the PM1 concentrations. The NR-PM1 was composed of organics (55 ± 15%), followed by sulfate (21 ± 9%), ammonium (13 ± 6%), nitrate (10 ± 6%) and chloride (1 ± 1%). Three major organic sources were identified using positive matrix factorization, namely primary organic aerosol (POA, 40 ± 19%), more-oxidized oxygenated OA (MO-OOA, 32 ± 22%) and less-oxidized oxygenated OA (LO-OOA, 28 ± 19%). Variations in organic groups, including alkanes, hopanes, steranes, polycyclic aromatic hydrocarbons (PAHs), oxy-PAHs (OPAHs), and fatty acids, demonstrated that traffic and cooking emissions were dominant pollution sources in this roadside station. Human lung alveolar epithelial (A549) cells were exposed to PM1, revealing increases in lactate dehydrogenase (LDH), reactive oxygen species (ROS), and interlukin-6 (IL-6), which indicated the occurrence of inflammatory and oxidative responses. POA was significantly associated with ROS and IL-6, and alkanes, hopanes, steranes, PAHs and OPAHs, and fatty acids presented medium to high correlations with LDH and IL-6, demonstrating the importance of primary emissions and organic compounds in cytotoxicity. This study demonstrated that organic compounds emitted from traffic and cooking play critical roles in PM-induced oxidative stress and inflammation in urban areas.
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Affiliation(s)
- Xinyi Niu
- The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China; School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China
| | - Yichen Wang
- School of Humanities, Economics and Law, Northwestern Polytechnical University, Xi'an, 710129, China
| | - Steven Sai Hang Ho
- Division of Atmospheric Sciences, Desert Research Institute, Reno, NV, 89512, United States; Hong Kong Premium Services and Research Laboratory, Hong Kong, China
| | - Hsiao-Chi Chuang
- School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Jian Sun
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China
| | - Linli Qu
- Hong Kong Premium Services and Research Laboratory, Hong Kong, China
| | - Gehui Wang
- Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, 210062, China
| | - Kin Fai Ho
- The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China.
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29
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Li J, Chen Q, Hua X, Chang T, Wang Y. Occurrence and sources of chromophoric organic carbon in fine particulate matter over Xi'an, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 725:138290. [PMID: 32294585 DOI: 10.1016/j.scitotenv.2020.138290] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/26/2020] [Accepted: 03/27/2020] [Indexed: 06/11/2023]
Abstract
Understanding the characteristics and sources of atmospheric chromophores is essential to assess their impact on climate change and the quality of atmospheric environment. In this work, the fine particulate matter (PM2.5) samples of Xi'an, China in 2017 were analyzed by excitation-emission matrices and parallel factor analysis (EEM-PARAFAC) method to obtain the species, content, sources and seasonal variation characteristics of atmospheric chromophores. The results showed that humic-like (HULIS) chromophores and polycyclic aromatic hydrocarbons-like (PAHs-like) chromophores were the most abundant chromophores in the samples, accounting for 42% and 33%, respectively. With the aggravation of air pollution, the relative content of low-polarity chromophores increased markedly, while the relative content of polar chromophores decreased. The concentrations of atmospheric chromophores exhibited obvious seasonal variation characteristics: high in winter and low in summer. Similarly, the relative contributions of atmospheric chromophores from each source varied with the season. In addition, special weather and human activities had a significant influence on the source of atmospheric chromophores. Dust source was an important source of atmospheric chromophores, which was susceptible to long-range incoming air masses from northwestern regions in spring. However, the chromophores from the dust source were easily removed by wet precipitation, which was the same as the chromophores from the combustion source. The chromophores from the combustion source were susceptible to human activities. The contribution of combustion source to atmospheric chromophores was reduced due to the implementation of air pollution control policies during the Chinese Spring Festival. In summer, the formation of photochemical secondary chromophores was more significant than in other seasons, and the photochemical secondary chromophores increased due to the formation of liquid phase reactions under high relative humidity conditions.
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Affiliation(s)
- Jinwen Li
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Qingcai Chen
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China.
| | - Xiaoyu Hua
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Tian Chang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China; Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Yuqin Wang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
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30
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Chen Q, Li J, Hua X, Jiang X, Mu Z, Wang M, Wang J, Shan M, Yang X, Fan X, Song J, Wang Y, Guan D, Du L. Identification of species and sources of atmospheric chromophores by fluorescence excitation-emission matrix with parallel factor analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 718:137322. [PMID: 32092515 DOI: 10.1016/j.scitotenv.2020.137322] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 01/27/2020] [Accepted: 02/13/2020] [Indexed: 06/10/2023]
Abstract
It is essential to fully understand the physicochemical properties and sources of atmospheric chromophores to evaluate their impacts on environmental quality and global climate. Three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy is an important method for directly characterizing the occurrences, origins, and chemical behaviors of atmospheric chromophores. However, there is still a lack of adequate information on the sources and chemical structures of EEM-defined chromophores. This situation limits the extensive application of the EEM method in the study of atmospheric chromophores. Under these adverse conditions, this work uses the analysis of EEM data by the parallel factor (PARAFAC) analysis model and a comprehensive comparison of the types and abundances of different chromophores in different aerosol samples (combustion source samples, secondary organic aerosols, and ambient aerosols) to demonstrate that the EEM method can distinguish among different chromophore types and aerosol sources. Indeed, approximately half of all fluorescent substances can be attributed to specific chemicals and sources. These findings provide an important basis for the study of the sources and chemical processes of atmospheric chromophores by the EEM approach.
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Affiliation(s)
- Qingcai Chen
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China.
| | - Jinwen Li
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Xiaoyu Hua
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Xiaotong Jiang
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Zhen Mu
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Mamin Wang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Jin Wang
- School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China
| | - Ming Shan
- Department of Building Science, School of Architecture, Tsinghua University, Beijing 100084, China
| | - Xudong Yang
- Department of Building Science, School of Architecture, Tsinghua University, Beijing 100084, China
| | - Xingjun Fan
- College of Resource and Environment, Anhui Science and Technology University, 233100, Anhui, China
| | - Jianzhong Song
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Yuqin Wang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Dongjie Guan
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Lin Du
- Environment Research Institute, Shandong University, Qingdao 266237, China.
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Wang Y, Wang M, Li S, Sun H, Mu Z, Zhang L, Li Y, Chen Q. Study on the oxidation potential of the water-soluble components of ambient PM 2.5 over Xi'an, China: Pollution levels, source apportionment and transport pathways. ENVIRONMENT INTERNATIONAL 2020; 136:105515. [PMID: 32006763 DOI: 10.1016/j.envint.2020.105515] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 01/17/2020] [Accepted: 01/20/2020] [Indexed: 06/10/2023]
Abstract
Reactive oxygen species (ROS) are a class of substances that are of general concern in terms of human health and are used to represent the oxidation potential (OP) of the atmosphere. In this study, the ROS levels in 116 daily fine particulate matter (PM2.5) samples taken over Xi'an in 2017 were measured with the dithiothreitol (DTT) method. The sources of DTTv (volume-based DTT consumption) in PM2.5 as well as their contributions were identified by both positive matrix factorization (PMF) and multiple linear regression (MLR) based on the measured chemical species in particulate matter (PM). The results showed that the yearly average DTTv over Xi'an was 0.53 nmol/min/m3 (0.19-1.10 nmol/min/m3). The highest DTTv level occurred in winter, followed by spring, summer and autumn. DTTv was the most strongly correlated with the water-soluble organic carbon (WSOC; r = 0.85), but the effects of WSOC on DTTv were very limited. SO2, NO2, CO, elemental carbon (EC) and K+ (r > 0.64) had moderate correlations with DTTv and were moderately related to environmentally persistent free radicals (EPFRs) (r = 0.56). The linear mixed-effects model showed that pollutants originating from incomplete combustion had greater effects on DTTv than those from complete combustion. Source apportionment results from PMF showed that motor vehicle emissions (27.4%), secondary sulfates (21.6%) and coal combustion sources (18.8%) were more important contributors to the DTTv in PM2.5 than dust sources (8.4%), metal processing (4.9%), industrial emissions (11.3%) and secondary nitrates (7.5%). The PMF results for the DTTv were consistent with the MLR results, which verified that both PMF and MLR are feasible methods for source apportionment of PM2.5 as well as specific species such as ROS and EPFRs. Backward trajectory clusters showed that the dominant cluster groups were local and regional transport, while the OP of the PM2.5 over Xi'an was affected more by long-range transport than by local transport. As stated above, the improvement of atmospheric oxidation potential require not only regional efforts but also large-scale joint cooperation. Furthermore, this study on the OP of PM as well as the specific source information provides important guidance for health effect research.
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Affiliation(s)
- Yuqin Wang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Mamin Wang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Shengping Li
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Haoyao Sun
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Zhen Mu
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Lixin Zhang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Yanguang Li
- Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits, MLR, Xi'an 710054, China; Xi'an Center of Geological Survey, China Geological Survey, Xi'an 710054, China
| | - Qingcai Chen
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China.
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Wang C, Huang Y, Zhang Z, Cai Z. Levels, spatial distribution, and source identification of airborne environmentally persistent free radicals from tree leaves. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 257:113353. [PMID: 31662268 DOI: 10.1016/j.envpol.2019.113353] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 10/04/2019] [Accepted: 10/04/2019] [Indexed: 05/16/2023]
Abstract
Environmentally persistent free radicals (EPFRs) are receiving increasing concern due to their toxicity and ubiquity in the environment. To avoid restrictions imposed when using a high-volume active sampler, this study uses tree leaves to act as passive samplers to investigate the spatial distribution characteristics and sources of airborne EPFRs. Tree leaf samples were collected from 120 sites in five areas around China (each approximately 4 km × 4 km). EPFR concentrations in particles (<2 μm) on the surface of 110 leaf samples were detected, ranging from 7.5 × 1016 to 4.5 × 1019 spins/g. For the 10 N.D. samples, they were all collected from areas inaccessible by vehicles. The g-values of EPFRs on 68% leaf samples were larger than 2.004, suggesting the electron localized on the oxygen atom, and they were consistent with the road dust sample (g-value: 2.0042). Significant positive correlation was found between concentrations of elemental carbon (tracer of vehicle emissions) and EPFRs. Spatial distribution mapping showed that EPFR levels in various land uses differed noticeably. Although previous work has linked atmospheric EPFRs to waste incineration, the evidence in this study suggests that vehicle emissions, especially from heavy-duty vehicles, are the main sources. While waste incinerators with low emissions or effective dust-control devices might not be an important EPFR contributor. According to our estimation, over 90% of the EPFRs deposited on tree leaves might be attributed to automotive exhaust emissions, as a synergistic effect of primary exhausts and degradation of aromatic compounds in road dust. With adding the trapping agent into the particle samples (<2 μm), signals of hydroxyl radicals were observed. This indicates that EPFRs collected from this phytosampling method can lead to the release of reactive oxygen species (ROS) once they are inhaled by human beings. Thus, this study helps highlight EPFR "hotspots" for potential health risk identification.
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Affiliation(s)
- Chen Wang
- School of Environmental Science and Engineering and Key Laboratory of Municipal Solid Waste Recycling Technology and Management of Shenzhen City, Southern University of Science and Technology, Shenzhen, 518055, PR China; State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, PR China
| | - Yanpeng Huang
- School of Environmental Science and Engineering and Key Laboratory of Municipal Solid Waste Recycling Technology and Management of Shenzhen City, Southern University of Science and Technology, Shenzhen, 518055, PR China
| | - Zuotai Zhang
- School of Environmental Science and Engineering and Key Laboratory of Municipal Solid Waste Recycling Technology and Management of Shenzhen City, Southern University of Science and Technology, Shenzhen, 518055, PR China.
| | - Zongwei Cai
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, PR China
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Yi P, Chen Q, Li H, Lang D, Zhao Q, Pan B, Xing B. A Comparative Study on the Formation of Environmentally Persistent Free Radicals (EPFRs) on Hematite and Goethite: Contribution of Various Catechol Degradation Byproducts. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:13713-13719. [PMID: 31682408 DOI: 10.1021/acs.est.9b04444] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The formation and occurrence of environmentally persistent free radicals (EPFRs) have recently attracted increasing research attention. The interactions between organics and transition metals and the crystalline forms of the transition metals are essential for EPFR formation. This study is thus designed to investigate catechol degradation and compare the characteristics of EPFRs on α-Fe2O3 (hematite, HM) and α-FeOOH (goethite, GT). Catechol degradation was inhibited in the dark in the presence of iron oxides. The inhibition was stronger on GT-silica, but the electron paramagnetic resonance (EPR) signals of the two systems were comparable. The enhanced degradation under UV light irradiation was comparable between HM-silica and GT-silica, but the EPR signals were stronger on GT-silica. Catechol was adsorbed on HM in a mononuclear bidentate (M-B) configuration, but it was adsorbed in both mononuclear monodentate (M-M) and binuclear bidentate (B-B) configurations on GT. After series analysis, we proposed that the dimer-type radical (2,2',3,3'-tetrahydroxy-1,1'-biphenylene) was responsible for the more stable EPR signals for the HM system, while the M-M structure was more favorable for the catechol stabilization. Note that in the analysis of EPFR formation mechanisms, it is important to consider (1) different crystalline lattices and (2) the contribution of the degradation byproducts of the parent organics.
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Affiliation(s)
- Peng Yi
- Faculty of Environmental Science & Engineering , Kunming University of Science & Technology , Kunming , 650500 , China
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control , Kunming , Yunnan 650500 , China
| | - Quan Chen
- Faculty of Environmental Science & Engineering , Kunming University of Science & Technology , Kunming , 650500 , China
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control , Kunming , Yunnan 650500 , China
| | - Hao Li
- Faculty of Environmental Science & Engineering , Kunming University of Science & Technology , Kunming , 650500 , China
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control , Kunming , Yunnan 650500 , China
| | - Di Lang
- Faculty of Environmental Science & Engineering , Kunming University of Science & Technology , Kunming , 650500 , China
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control , Kunming , Yunnan 650500 , China
| | - Qing Zhao
- Institute of Applied Ecology , Chinese Academy of Sciences , Shenyang 110016 , China
| | - Bo Pan
- Faculty of Environmental Science & Engineering , Kunming University of Science & Technology , Kunming , 650500 , China
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control , Kunming , Yunnan 650500 , China
| | - Baoshan Xing
- Stockbridge School of Agriculture , University of Massachusetts , Amherst , Massachusetts 01003 , United States
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Xu M, Wu T, Tang YT, Chen T, Khachatryan L, Iyer PR, Guo D, Chen A, Lyu M, Li J, Liu J, Li D, Zuo Y, Zhang S, Wang Y, Meng Y, Qi F. Environmentally persistent free radicals in PM 2.5: a review. ACTA ACUST UNITED AC 2019; 1:177-197. [PMID: 34308260 DOI: 10.1007/s42768-019-00021-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Environmentally persistent free radicals (EPFRs) are a new class of pollutants that are long-lived in fine particles (PM2.5), i.e., their 1/e lifetime ranges from days to months (or even infinite). They are capable of producing harmful reactive oxygen species such as hydroxyl radicals. The redox cycling of EPFRs is considered as an important pathway for PM2.5 to induce oxidative stress inside the humans, causing adverse health effects such as respiratory and cardiovascular diseases. Consequently, research regarding their toxicity, formation and environmental occurrences in PM2.5 has attracted increasing attentions globally during the past two decades. However, literature data in this field remain quite limited and discrete. Hence, an extensive review is urgently needed to summarize the current understanding of this topic. In this work, we systematically reviewed the analytical methods and environmental occurrences, e.g., types, concentrations, and decay behaviors, as well as possible sources of EPFRs in PM2.5. The types of pretreatment methods, g-values of common EPFRs and categories of decay processes were discussed in detail. Moreover, great efforts were made to revisit the original data of the published works of EPFRs in airborne particulate matter and provided additional useful information for comparison where possible, e.g., their mean and standard deviation of g-values, line widths (ΔH p-p), and concentrations. Finally, possible research opportunities were highlighted to further advance our knowledge of this emerging issue.
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Affiliation(s)
- Mengxia Xu
- Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China.,New Materials Institute, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Tao Wu
- Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China.,New Materials Institute, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Yu-Ting Tang
- School of Geographical Sciences, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Tong Chen
- State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China
| | - Lavrent Khachatryan
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Poornima Ramesh Iyer
- Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Dengting Guo
- Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Anran Chen
- Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Miao Lyu
- Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Jinhu Li
- Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Jiaqi Liu
- Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Dan Li
- Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Yuxin Zuo
- Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Shihan Zhang
- Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Yiran Wang
- Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Yining Meng
- Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
| | - Fei Qi
- Department of Chemical and Environmental Engineering, University of Nottingham Ningbo China, Ningbo 315100, China
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Wang Y, Li S, Wang M, Sun H, Mu Z, Zhang L, Li Y, Chen Q. Source apportionment of environmentally persistent free radicals (EPFRs) in PM 2.5 over Xi'an, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 689:193-202. [PMID: 31271986 DOI: 10.1016/j.scitotenv.2019.06.424] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 06/23/2019] [Accepted: 06/25/2019] [Indexed: 06/09/2023]
Abstract
Environmentally persistent free radicals (EPFRs) have recently attracted considerable attention as a new type of environmental risk substance due to their potential health effects. However, the sources and contributions of EPFRs in PM2.5 are not yet clear. Therefore, this study reports the sources of EPFRs in PM2.5 based on chemical analysis and positive matrix factorization (PMF). Daily PM2.5 samples (116) were collected in Xi'an city from April 4 to December 29, 2017, and were quantitatively analyzed for EPFRs and other chemical constituents. The PMF model revealed contributions from five main sources of EPFRs in PM2.5 (dust sources, coal combustion, secondary nitrates, industrial emissions and motor vehicle emissions). Coal combustion, motor vehicle emissions and dust sources are the top three contributors to EPFRs (76.12% in total). Coal combustion is highly important for PM2.5 (35.10%) and EPFRs (16.75%). A high dust source contribution to EPFRs in spring may be due to dust storm events. Motor vehicle emissions are the top contributor to EPFRs, with a mean percentage of 32.13%. Secondary nitrates barely contributes to EPFRs (3.42%), indicating an EPFR origin from primary emissions rather than secondary inorganic reactions. Industrial emissions contribute less to PM2.5 (4.31%) than to EPFRs (11.71%), which implies that fossil fuels contains many high-molecular-weight organics that could emit EPFRs. Integrating the PMF results with meteorological data revealed that atmospheric pollutants emitted in Xi'an city center could be transported to the sampling site by southern winds. These results suggest the need for further studies on the public health effects of EPFRs and can be used to help formulate source control measures to reduce the potential health risks posed by EPFRs in PM2.5.
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Affiliation(s)
- Yuqin Wang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China; Department of Earth and Atmospheric Sciences, Saint Louis University, St. Louis, MO 63108, USA
| | - Shengping Li
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Mamin Wang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Haoyao Sun
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Zhen Mu
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Lixin Zhang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Yanguang Li
- Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits, MLR, Xi'an 710054, China; Xi'an Center of Geological Survey, China Geological Survey, Xi'an 710054, China
| | - Qingcai Chen
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China.
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36
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Chen Q, Sun H, Wang M, Wang Y, Zhang L, Han Y. Environmentally Persistent Free Radical (EPFR) Formation by Visible-Light Illumination of the Organic Matter in Atmospheric Particles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:10053-10061. [PMID: 31389239 DOI: 10.1021/acs.est.9b02327] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A secondary process may be an important source of environmentally persistent free radicals (EPFRs) in atmospheric particulates; yet, this process remains to be elucidated. This study demonstrated that secondary EPFRs could be generated by visible-light illumination of atmospheric particulate matter (PM), and their lifetimes were only 30 min to 1 day, which were much shorter than the lifetimes of the original EPFRs in PM. The yields of secondary EPFRs produced by PM could reach 15-60% of those of the original EPFRs. The extractable organic matter contributed to the formation of secondary EPFRs (∼55%), and a humic-like substance was the main precursor of the secondary EPFRs and was also the most productive precursor compared to the other aerosol components. The results of simulation experiments showed that the secondary EPFRs generated by the extractable and nonextractable PM components were similar to those produced by phenolic compounds and polycyclic aromatic hydrocarbons, respectively. We have found that oxygen molecules play an important role in the photochemical generation and decay of EPFRs. The reactive oxygen capture experiments showed that the original EPFRs may contribute to singlet oxygen generation, while the secondary EPFRs generated by photoexcitation may not produce singlet oxygen or hydroxyl radicals.
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Affiliation(s)
- Qingcai Chen
- School of Environmental Science and Engineering , Shaanxi University of Science and Technology , Xi'an 710021 , China
| | - Haoyao Sun
- School of Environmental Science and Engineering , Shaanxi University of Science and Technology , Xi'an 710021 , China
| | - Mamin Wang
- School of Environmental Science and Engineering , Shaanxi University of Science and Technology , Xi'an 710021 , China
| | - Yuqin Wang
- School of Environmental Science and Engineering , Shaanxi University of Science and Technology , Xi'an 710021 , China
| | - Lixin Zhang
- School of Environmental Science and Engineering , Shaanxi University of Science and Technology , Xi'an 710021 , China
| | - Yuemei Han
- Key Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology , Institute of Earth Environment, Chinese Academy of Sciences , Xi'an 710061 , China
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Zhao S, Gao P, Miao D, Wu L, Qian Y, Chen S, Sharma VK, Jia H. Formation and Evolution of Solvent-Extracted and Nonextractable Environmentally Persistent Free Radicals in Fly Ash of Municipal Solid Waste Incinerators. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:10120-10130. [PMID: 31403286 DOI: 10.1021/acs.est.9b03453] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Environmentally persistent free radicals (EPFRs) are emerging contaminants occurring in combustion-borne particulates and atmospheric particulate matter, but information on their formation and behavior on fly ash from municipal solid waste (MSW) incinerators is scarce. Here, we have found that MSW-associated fly ash samples contain an EPFR concentration of 3-10 × 1015 spins g-1, a line width (ΔHp-p) of ∼8.6 G, and a g-factor of 2.0032-2.0038. These EPFRs are proposed to be mixtures of carbon-centered and oxygen-centered free radicals. Fractionation of the fly ash-associated EPFRs into solvent-extracted and nonextractable radicals suggests that the solvent-extracted part accounts for ∼45-73% of the total amount of EPFRs. Spin densities of solvent-extracted EPFRs correlate positively with the concentrations of Fe, Cu, Mn, Ti, and Zn, whereas similar correlations are comparatively insignificant for nonextractable EPFRs. Under natural conditions, these two types of EPFRs exhibit different stabilization that solvent-extracted EPFRs are relatively unstable, whereas the nonextractable fraction possesses a long life span. Significant correlations between concentrations of solvent-extracted EPFRs and generation of hydroxyl and superoxide radicals are found. Overall, our results suggest that the fractionated solvent-extracted and nonextractable EPFRs may experience different formation and stabilization processes and health effects.
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Affiliation(s)
- Song Zhao
- College of Natural Resources and Environment; State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Institute of Soil and Water Conservation , Northwest A & F University , Yangling 712100 , China
| | - Pin Gao
- College of Environmental Science and Engineering , Donghua University , Shanghai 201620 , China
| | - Duo Miao
- College of Natural Resources and Environment; State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Institute of Soil and Water Conservation , Northwest A & F University , Yangling 712100 , China
| | - Lan Wu
- College of Natural Resources and Environment; State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Institute of Soil and Water Conservation , Northwest A & F University , Yangling 712100 , China
| | - Yajie Qian
- College of Environmental Science and Engineering , Donghua University , Shanghai 201620 , China
| | - Shanping Chen
- Shanghai Environmental Sanitation Engineering Design Institute Co., Ltd. , Shanghai 200232 , China
| | - Virender K Sharma
- Program for the Environment and Sustainability, Department of Occupational and Environmental Health, School of Public Health , Texas A&M University , College Station , Texas 77843 , United States
| | - Hanzhong Jia
- College of Natural Resources and Environment; State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Institute of Soil and Water Conservation , Northwest A & F University , Yangling 712100 , China
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Chen Q, Wang M, Wang Y, Zhang L, Li Y, Han Y. Oxidative Potential of Water-Soluble Matter Associated with Chromophoric Substances in PM 2.5 over Xi'an, China. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:8574-8584. [PMID: 31248249 DOI: 10.1021/acs.est.9b01976] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Organic compounds are important contributors to the oxidative potential (OP) of atmospheric aerosols. This study is the first to report the OP of water-soluble organic matter (WSOM) related to the chromophoric substances in PM2.5 over Xi'an, China. The dithiothreitol (DTT) activity levels in PM2.5 extracted by water were quantified as well as the relationships between DTT activity and light absorption and fluorescence properties. The results show that the DTT activity has significantly correlated with colored WSOM, in which we identified three light absorbing substances (BrC1-3) and eight fluorescent substances (C1-8). It is further found that BrC3 and C7 accounted for almost all of the DTT activity by colored WSOM, although these two factors contributed only a small fraction of light absorption and fluorescence. BrC3 and C7 are clearly distinguished from other chromophoric substances because of their long absorption wavelength (λmax = 475 nm) and fluorescence emission wavelength (λmax = 462 nm), respectively. This discovery will help to better interpret and understand the mechanism of oxidation activity generation by light absorbing organic aerosols and provide guidance for predicting the OPs of light absorbing organic aerosols based on their optical properties.
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Affiliation(s)
- Qingcai Chen
- School of Environmental Science and Engineering , Shaanxi University of Science and Technology , Xi'an 710021 , China
| | - Mamin Wang
- School of Environmental Science and Engineering , Shaanxi University of Science and Technology , Xi'an 710021 , China
| | - Yuqin Wang
- School of Environmental Science and Engineering , Shaanxi University of Science and Technology , Xi'an 710021 , China
- Department of Earth and Atmospheric Sciences , Saint Louis University , St. Louis , Missouri 63108 , United States
| | - Lixin Zhang
- School of Environmental Science and Engineering , Shaanxi University of Science and Technology , Xi'an 710021 , China
| | - Yanguang Li
- Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits, MLR , Xi'an 710054 , China
- Xi'an Center of Geological Survey , China Geological Survey , Xi'an 710054 , China
| | - Yuemei Han
- Key Laboratory of Aerosol Chemistry and Physics, State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment , Chinese Academy of Sciences , Xi'an 710061 , China
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Pan B, Li H, Lang D, Xing B. Environmentally persistent free radicals: Occurrence, formation mechanisms and implications. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 248:320-331. [PMID: 30802746 DOI: 10.1016/j.envpol.2019.02.032] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 02/10/2019] [Accepted: 02/11/2019] [Indexed: 05/23/2023]
Abstract
Environmentally persistent free radicals (EPFRs) are defined as organic free radicals stabilized on or inside particles. They are persistent because of the protection by the particles and show significant toxicity to organisms. Increasing research interests have been attracted to study the potential environmental implications of EPFRs. Because of their different physical forms from conventional contaminants, it is not applicable to use the commonly used technique and strategy to predict and assess the behavior and risks of EPFRs. Current studies on EPFRs are scattered and not systematic enough to draw clear conclusions. Therefore, this review is organized to critically discuss the current research progress on EPFRs, highlighting their occurrence and transport, generation mechanisms, as well as their environmental implications (including both toxicity and reactivity). EPFR formation and stabilization as affected by the precursors and environmental factors are useful breakthrough to understand their formation mechanisms. To better understand the major differences between EPFRs and common contaminants, we identified the unique processes and/or mechanisms related to EPFRs. The knowledge gaps will be also addressed to highlight the future research while summarizing the research progress. Quantitative analysis of the interactions between organic contaminants and EPFRs will greatly improve the predictive accuracy of the multimedia environmental fate models. In addition, the health risks will be better evaluated when considering the toxicity contributed by EFPRs.
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Affiliation(s)
- Bo Pan
- Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, 650500, Yunnan, China; Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control in Soils, Kunming, 650500, Yunnan, China
| | - Hao Li
- Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, 650500, Yunnan, China; Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control in Soils, Kunming, 650500, Yunnan, China; Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, 01003, United States
| | - Di Lang
- Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, 650500, Yunnan, China; Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control in Soils, Kunming, 650500, Yunnan, China
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, 01003, United States.
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He W, Liu WX, Qin N, Kong XZ, He QS, Xu FL. Impact of organic matter and meteorological factors on the long-term trend, seasonality, and gas/particle partitioning behavior of atmospheric PBDEs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 659:1058-1070. [PMID: 31096321 DOI: 10.1016/j.scitotenv.2018.12.411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 12/25/2018] [Accepted: 12/27/2018] [Indexed: 06/09/2023]
Abstract
We extended our knowledge of the impact of organic matter (OM) and meteorological factors on the long-term trend, seasonality and gas/particle partitioning behavior of polybrominated diphenyl ethers (PBDEs). In Lake Chaohu, PBDEs had an increasing trend, with a doubling time of 13.4 years at the urban site, and a decreasing trend, with a halving time of 6.1 years at the rural site. At the urban site, the negative association of OM with most congeners indicated that the graphene-like carbonaceous components might carry or release PBDEs, and the negative association of long-term rain fall and wind speed with most congeners was suggested to dilute or increase the transport speed of PBDEs in the atmosphere. At the rural site, the negative association with PM10 and positive association with OM indicated that the PBDEs-buried OM was mainly from non-local sources. Restricted to the temperature seasonality, the frequency of PBDE congeners decreased with seasonality from 64% and 43% to 50% and 43% at the urban and rural sites, respectively. The slope of the simplified Pankow adsorption model in samples with larger absolute OM content (>10 μgC m-3) was steeper than that with lower absolute OM content (<5 μgC m-3), indicating that OM facilitated the gas-particle partitioning equilibrium. Interestingly, the theoretic partitioning coefficients were much lower than the measured ones for less brominated BDEs, whereas the highly brominated BDEs did the opposite. The theoretic partitioning coefficient should be further modified by considering the molecular weight distribution of the OM and the corresponding activity coefficients of the target compound in a specific type of OM phase.
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Affiliation(s)
- Wei He
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China; MOE Key Laboratory for Earth Surface Process, College of Urban & Environmental Sciences, Peking University, Beijing 100871, China
| | - Wen-Xiu Liu
- MOE Key Laboratory for Earth Surface Process, College of Urban & Environmental Sciences, Peking University, Beijing 100871, China
| | - Ning Qin
- School of Energy and Environmental Engineering, Beijing University of Science and Technology, Beijing 100083, China
| | - Xiang-Zhen Kong
- MOE Key Laboratory for Earth Surface Process, College of Urban & Environmental Sciences, Peking University, Beijing 100871, China
| | - Qi-Shuang He
- Beijing Municipal Key Laboratory of Agriculture Environment Monitoring, Beijing 100097, China
| | - Fu-Liu Xu
- MOE Key Laboratory for Earth Surface Process, College of Urban & Environmental Sciences, Peking University, Beijing 100871, China.
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Chen Q, Sun H, Mu Z, Wang Y, Li Y, Zhang L, Wang M, Zhang Z. Characteristics of environmentally persistent free radicals in PM 2.5: Concentrations, species and sources in Xi'an, Northwestern China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 247:18-26. [PMID: 30650344 DOI: 10.1016/j.envpol.2019.01.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 01/03/2019] [Accepted: 01/04/2019] [Indexed: 05/07/2023]
Abstract
Environmentally persistent free radicals (EPFRs) are a new class of environmental risk substances that can stably exist in atmospheric particles and pose a potential threat to human health. In this study, electron paramagnetic resonance (EPR) spectroscopy was used to study the concentration levels, species characteristics, and sources of EPFRs in PM2.5 in Xi'an in 2017. The results showed that the concentrations of EPFRs in PM2.5 in Xi'an in 2017 ranged from 9.8 × 1011 to 6.9 × 1014 spins/m3. The highest concentration of EPFRs occurred in winter when the average concentration was 2.1 × 1014 spins/m3. The lowest concentration of EPFRs occurred in autumn when the average concentration was 7.0 × 1013 spins/m3. According to the annual average atmospheric concentration of EPFRs, the amount of EPFRs inhaled by people in Xi'an is equivalent to approximately 5 cigarettes per person per day and approximately 23 cigarettes per person per day in winter when haze occurs. The results of the study on the EPFR characteristics show that the EPFRs in PM2.5 in Xi'an are mainly C-center organic radicals that are primarily non-decaying types, accounting for approximately 75% and 85% of total concentration of EPFRs in autumn and winter, respectively. Finally, a correlation analysis was used to explore the origins of EPFRs in PM2.5. Significant positive correlations were found between EPFRs and SO2, NO2 and the thermally derived OC3 and OC4 carbonaceous components. The results suggested that coal-fired and traffic may be important sources of EPFRs in PM2.5 in Xi'an. In addition, EPFRs are significantly positively correlated with O3 in summer, suggesting that some EPFRs may also originate from secondary processes. This study provides important basic data and evidence for further assessments of the potential health risks of EPFRs in PM2.5 and the development of effective air pollution control measures.
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Affiliation(s)
- Qingcai Chen
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China.
| | - Haoyao Sun
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China
| | - Zhen Mu
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China
| | - Yuqin Wang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China
| | - Yanguang Li
- Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits, MLR, Xi'an, 710054, China; Xi'an Center of Geological Survey, China Geological Survey, Xi'an, 710054, China
| | - Lixin Zhang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China
| | - Mamin Wang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China
| | - Zimeng Zhang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China
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Chen Q, Wang M, Sun H, Wang X, Wang Y, Li Y, Zhang L, Mu Z. Enhanced health risks from exposure to environmentally persistent free radicals and the oxidative stress of PM 2.5 from Asian dust storms in Erenhot, Zhangbei and Jinan, China. ENVIRONMENT INTERNATIONAL 2018; 121:260-268. [PMID: 30223202 DOI: 10.1016/j.envint.2018.09.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 08/22/2018] [Accepted: 09/06/2018] [Indexed: 05/19/2023]
Abstract
Asian dust storms can increase the level of atmospheric pollution over regions downwind of dust storms and may have adverse health effects on residents along the sandstorm transmission route. This study was the first to report the concentration levels, properties and possible sources of environmentally persistent free radicals (EPFRs) and oxidative potential in atmospheric PM2.5 at the three sites of Erenhot, Zhangbei, and Jinan along the transport route of Asian dust storms during the occurrence of Asian dust storms in the spring of 2016. Under non-sandstorm weather conditions, the average EPFR concentrations at the three sites were Zhangbei>Jinan>Erenhot, while the PM-induced oxidative potential levels were Erenhot>Jinan>Zhangbei. The PM2.5 concentration increased significantly during dust storm events, and the total atmospheric concentration of EPFRs (spins/m3) and total oxidation potential (a.u./m3) of PM2.5 simultaneously increased. However, the EPFR concentration in PM2.5 (spins/g) and the unit mass of the PM oxidation potential (a.u./g) were significantly reduced. Electron paramagnetic resonance analysis combined with backward trajectory analysis and MODIS products showed that Asian dust storms can carry EPFRs over long distances. Correlation analysis showed that the atmospheric concentrations of EPFRs were positively correlated with elemental carbon (EC) for the Zhangbei and Jinan samples but were not significantly correlated with EC for the Erenhot samples, indicating that combustion may be an important source of EPFRs for the Zhangbei and Jinan samples. In contrast, the EPFRs in the Erenhot samples were more affected by dust/sand. The EPFR concentration levels showed a significant positive correlation with the oxidation potentials for the Erenhot and Zhangbei samples and showed negative correlations for the Jinan samples, suggesting that the EPFRs in the Erenhot and Zhangbei samples may provide an important contribution to the oxidative stress in PM2.5. In contrast, the oxidation potential for the Jinan samples was mainly caused by substances other than EPFRs. This study presents a basic understanding of the potential health effects of Asian dust storms, and this information can be used to assess the health risks of Asian dust storms in future studies.
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Affiliation(s)
- Qingcai Chen
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China.
| | - Mamin Wang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Haoyao Sun
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Xin Wang
- Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China.
| | - Yuqin Wang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China; Department of Earth and Atmospheric Sciences, Saint Louis University, St. Louis, MO 63108, USA
| | - Yanguang Li
- Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits, MLR, Xi'an 710054, China; Xi'an Center of Geological Survey, China Geological Survey, Xi'an 710054, China
| | - Lixin Zhang
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
| | - Zhen Mu
- School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
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