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He R, Zhang J, Chen L, Zhang W, Xi Y. Characterization of Fe-containing particles in Chengdu, southwest China, using single-particle aerosol mass spectrometry. J Environ Sci (China) 2024; 136:110-120. [PMID: 37923423 DOI: 10.1016/j.jes.2022.10.001] [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: 06/23/2022] [Revised: 10/03/2022] [Accepted: 10/03/2022] [Indexed: 11/07/2023]
Abstract
Single-particle aerosol mass spectrometry was used to study the characteristics of Fe-containing particles during winter in Chengdu, southwest China. The mass concentrations of PM2.5 and PM10 during the study period were 64 ± 38 and 89 ± 49 µg/m3, respectively, and NO2 and particulate matter were high compared with most other regions of China. The Fe-containing particles were divided into seven categories with different mass spectra, sources and aging characteristics. The highest contribution was from Fe mixed with carbonaceous components (Fe-C, 23.1%) particles. Fe was more mixed with sulfate than nitrate and therefore the contribution of Fe mixed with sulfate (Fe-S, 20.7%) particles was higher than that of Fe mixed with nitrate (Fe-N, 12.5%) particles. The contributions from Fe-containing particles related to primary combustion were high in the small particle size range, whereas aged Fe-containing particles and dust-related particles were mostly found in the coarse particle size range. The air masses mainly originated from the west and east of Chengdu, and the corresponding PM2.5 concentrations were 79 ± 36 and 55 ± 36 µg/m3, respectively. The west and east air masses showed stronger contributions of Fe-containing particles related to biomass burning (Fe-B) and fossil fuel combustion (Fe-C and Fe-S) particles, respectively. The southwest area contributed the most Fe-containing particles. Future assessments of the effects of Fe-containing particles during heavy pollution period should pay more attention to Fe-C and Fe-S particles. Emission-reduction of Fe-containing particles should consider both local emissions and short-distance transmission from the surrounding areas.
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Affiliation(s)
- Renjiang He
- School of Public Health, Southwest Medical University, Luzhou 646000, China
| | - Junke Zhang
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 611756, China.
| | - Luyao Chen
- Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 611756, China
| | - Wei Zhang
- Sichuan Environmental Monitoring Center, Chengdu 610074, China
| | - Yingwei Xi
- Sichuan Environmental Monitoring Center, Chengdu 610074, China
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2
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Al-Abadleh HA. Iron content in aerosol particles and its impact on atmospheric chemistry. Chem Commun (Camb) 2024. [PMID: 38268472 DOI: 10.1039/d3cc04614a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2024]
Abstract
Atmospheric aerosol effects on ecological and human health remain uncertain due to their highly complex and evolving nature when suspended in air. Atmospheric chemistry, global climate/oceanic and health exposure models need to incorporate more realistic representations of aerosol particles, especially their bulk and surface chemistry, to account for the evolution in aerosol physicochemical properties with time. (Photo)chemistry driven by iron (Fe) in atmospheric aerosol particles from natural and anthropogenic sources remains limited in these models, particularly under aerosol liquid water conditions. In this feature article, recent advances from our work on Fe (photo)reactivity in multicomponent aerosol systems are highlighted. More specifically, reactions of soluble Fe with aqueous extracts of biomass burning organic aerosols and proxies of humic like substances leading to brown carbon formation are presented. Some of these reactions produced nitrogen-containing gaseous and condensed phase products. For comparison, results from these bulk aqueous phase chemical studies were compared to those from heterogeneous reactions simulating atmospheric aging of Fe-containing reference materials. These materials include Arizona test dust (AZTD) and combustion fly ash particles. Also, dissolution of Fe and other trace elements is presented from simulated human exposure experiments to highlight the impact of aerosol aging on levels of trace metals. The impacts of these chemical reactions on aerosol optical, hygroscopic and morphological properties are also emphasized in light of their importance to aerosol-radiation and aerosol-cloud interactions, in addition to biogeochemical processes at the sea/ocean surface microlayer upon deposition. Future directions for laboratory studies on Fe-driven multiphase chemistry are proposed to advance knowledge and encourage collaborations for efficient utilization of expertise and resources among climate, ocean and health scientific communities.
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Affiliation(s)
- Hind A Al-Abadleh
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, ON, N2L 3C5, Canada.
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3
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Chen K, Mayorga R, Hamilton C, Bahreini R, Zhang H, Lin YH. Contribution of Carbonyl Chromophores in Secondary Brown Carbon from Nighttime Oxidation of Unsaturated Heterocyclic Volatile Organic Compounds. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:20085-20096. [PMID: 37983166 DOI: 10.1021/acs.est.3c08872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The light absorption properties of brown carbon (BrC), which are linked to molecular chromophores, may play a significant role in the Earth's energy budget. While nitroaromatic compounds have been identified as strong chromophores in wildfire-driven BrC, other types of chromophores remain to be investigated. Given the electron-withdrawing nature of carbonyls ubiquitous in the atmosphere, we characterized carbonyl chromophores in BrC samples from the nighttime oxidation of furan and pyrrole derivatives, which are important but understudied precursors of secondary organic aerosols primarily found in wildfire emissions. Various carbonyl chromophores were characterized and quantified in BrC samples, and their ultraviolet-visible spectra were simulated by using time-dependent density functional theory. Our findings suggest that chromophores with carbonyls bonded to nitrogen (i.e., imides and amides) derived from N-containing heterocyclic precursors substantially contribute to BrC light absorption. The quantified N-containing carbonyl chromophores contributed to over 40% of the total light absorption at wavelengths below 350 nm and above 430 nm in pyrrole BrC. The contributions of chromophores to total light absorption differed significantly by wavelength, highlighting their divergent importance in different wavelength ranges. Overall, our findings highlight the significance of carbonyl chromophores in secondary BrC and underscore the need for further investigation.
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Affiliation(s)
- Kunpeng Chen
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States
| | - Raphael Mayorga
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Caitlin Hamilton
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Roya Bahreini
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States
| | - Haofei Zhang
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Ying-Hsuan Lin
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States
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Chen Z, Li H, Shang H, Liu X, Guo F, Liu X, Yu L, Zhou B, Liu X, Shi Y, Zhang L, Ai Z. Oxalate-Promoted SO 2 Uptake and Oxidation on Iron Minerals: Implications for Secondary Sulfate Aerosol Formation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:13559-13568. [PMID: 37647604 DOI: 10.1021/acs.est.3c03369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Mineral dust serves as a significant source of sulfate aerosols by mediating heterogeneous sulfur dioxide (SO2) oxidation in the atmosphere. Given that a considerable proportion of small organic acids are deposited onto mineral dust via long-range transportation, understanding their impact on atmospheric SO2 transformation and sulfate formation is of great importance. This study investigates the effect of oxalate on heterogeneous SO2 uptake and oxidation phenomenon by in situ FTIR, theoretical calculation, and continuous stream experiments, exploiting hematite (Fe2O3) as an environmental indicator. The results highlight the critical role of naturally deposited oxalate in mononuclear monodentate coordinating surface Fe atoms of Fe2O3 that enhances the activation of O2 for oxidizing SO2 into sulfate. Meanwhile, oxalate increases the hygroscopicity of Fe2O3, facilitating H2O dissociation into reactive hydroxyl groups and further augmenting the SO2 uptake capacity of Fe2O3. More importantly, other conventional iron minerals, such as goethite and magnetite, as well as authentic iron-containing mineral dust, exhibit similar oxalate-promoted sulfate accumulation behaviors. Our findings suggest that oxalate-assisted SO2 oxidation on iron minerals is one of the important contributors to secondary sulfate aerosols, especially during the nighttime with high relative humidity.
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Affiliation(s)
- Ziyue Chen
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Hao Li
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Huan Shang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Xupeng Liu
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Furong Guo
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Xiufan Liu
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Linghao Yu
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Biao Zhou
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Xiao Liu
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Yanbiao Shi
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Lizhi Zhang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Zhihui Ai
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
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Li F, Tang S, Lv J, He A, Wang Y, Liu S, Cao H, Zhao L, Wang Y, Jiang G. Molecular-Scale Investigation on the Formation of Brown Carbon Aerosol via Iron-Phenolic Compound Reactions in the Dark. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:11173-11184. [PMID: 37462533 DOI: 10.1021/acs.est.3c04263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Brown carbon (BrC) is one of the most mysterious aerosol components responsible for global warming and air pollution. Iron (Fe)-induced catalytic oxidation of ubiquitous phenolic compounds has been considered as a potential pathway for BrC formation in the dark. However, the reaction mechanism and product composition are still poorly understood. Herein, 13 phenolic precursors were employed to react with Fe under environmentally relevant conditions. Using Fourier transform ion cyclotron resonance mass spectrometry, a total of 764 unique molecular formulas were identified, and over 85% of them can be found in atmospheric aerosols. In particular, products derived from precursors with catechol-, guaiacol-, and syringol-like-based structures can be distinguished by their optical and molecular characteristics, indicating the structure-dependent formation of BrC from phenolic precursors. Multiple pieces of evidence indicate that under acidic conditions, the contribution of either autoxidation or oxygen-induced free radical oxidation to BrC formation is extremely limited. Ligand-to-Fe charge transfer and subsequent phenoxy radical coupling reactions were the main mechanism for the formation of polymerization products with high molecular diversity, and the efficiency of BrC generation was linearly correlated with the ionization potential of phenolic precursors. The present study uncovered how chemically diverse BrC products were formed by the Fe-phenolic compound reactions at the molecular level and also provide a new paradigm for the study of the atmospheric aerosol formation mechanism.
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Affiliation(s)
- Feifei Li
- State Key Laboratory of Environmental Chemistry and Eco-toxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shanshan Tang
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
| | - Jitao Lv
- State Key Laboratory of Environmental Chemistry and Eco-toxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Anen He
- State Key Laboratory of Environmental Chemistry and Eco-toxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yarui Wang
- State Key Laboratory of Environmental Chemistry and Eco-toxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuting Liu
- State Key Laboratory of Environmental Chemistry and Eco-toxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huiming Cao
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Lixia Zhao
- State Key Laboratory of Environmental Chemistry and Eco-toxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
| | - Yawei Wang
- State Key Laboratory of Environmental Chemistry and Eco-toxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
| | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and Eco-toxicology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
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Li F, Zhou S, Du L, Zhao J, Hang J, Wang X. Aqueous-phase chemistry of atmospheric phenolic compounds: A critical review of laboratory studies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:158895. [PMID: 36130630 DOI: 10.1016/j.scitotenv.2022.158895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/12/2022] [Accepted: 09/16/2022] [Indexed: 06/15/2023]
Abstract
Phenolic compounds (PhCs) are crucial atmospheric pollutants typically emitted by biomass burning and receive particular concerns considering their toxicity, light-absorbing properties, and involvement in secondary organic aerosol (SOA) formation. A comprehensive understanding of the transformation mechanisms on chemical reactions in atmospheric waters (i.e., cloud/fog droplets and aerosol liquid water) is essential to predict more precisely the atmospheric fate and environmental impacts of PhCs. Laboratory studies play a core role in providing the fundamental knowledge of aqueous-phase chemical transformations in the atmosphere. This article critically reviews recent laboratory advances in SOA formation from the aqueous-phase reactions of PhCs. It focuses primarily on the aqueous oxidation of PhCs driven by two atmospheric reactive species: OH radicals and triplet excited state organics, including the important chemical kinetics and mechanisms. The effects of inorganic components (i.e., nitrate and nitrite) and transition metal ions (i.e., soluble iron) are highlighted on the aqueous-phase transformation of PhCs and on the properties and formation mechanisms of SOA. The review is concluded with the current knowledge gaps and future perspectives for a better understanding of the atmospheric transformation and SOA formation potential of PhCs.
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Affiliation(s)
- Fenghua Li
- School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China
| | - Shengzhen Zhou
- School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China; Guangdong Provincial Field Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Sun Yat-sen University, Guangzhou 510275, China; Key Laboratory of Tropical Atmosphere-Ocean System, Ministry of Education, Zhuhai 519082, China.
| | - Lin Du
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Jun Zhao
- School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China; Guangdong Provincial Field Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Sun Yat-sen University, Guangzhou 510275, China; Key Laboratory of Tropical Atmosphere-Ocean System, Ministry of Education, Zhuhai 519082, China
| | - Jian Hang
- School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China; Guangdong Provincial Field Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary, Sun Yat-sen University, Guangzhou 510275, China; Key Laboratory of Tropical Atmosphere-Ocean System, Ministry of Education, Zhuhai 519082, China
| | - Xuemei Wang
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Institute for Environmental and Climate Research, Jinan University, Guangzhou 510000, China
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Al-Abadleh HA, Motaghedi F, Mohammed W, Rana MS, Malek KA, Rastogi D, Asa-Awuku AA, Guzman MI. Reactivity of aminophenols in forming nitrogen-containing brown carbon from iron-catalyzed reactions. Commun Chem 2022; 5:112. [PMID: 36697654 PMCID: PMC9814260 DOI: 10.1038/s42004-022-00732-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 09/07/2022] [Indexed: 01/28/2023] Open
Abstract
Nitrogen-containing organic carbon (NOC) in atmospheric particles is an important class of brown carbon (BrC). Redox active NOC like aminophenols received little attention in their ability to form BrC. Here we show that iron can catalyze dark oxidative oligomerization of o- and p-aminophenols under simulated aerosol and cloud conditions (pH 1-7, and ionic strength 0.01-1 M). Homogeneous aqueous phase reactions were conducted using soluble Fe(III), where particle growth/agglomeration were monitored using dynamic light scattering. Mass yield experiments of insoluble soot-like dark brown to black particles were as high as 40%. Hygroscopicity growth factors (κ) of these insoluble products under sub- and super-saturated conditions ranged from 0.4-0.6, higher than that of levoglucosan, a prominent proxy for biomass burning organic aerosol (BBOA). Soluble products analyzed using chromatography and mass spectrometry revealed the formation of ring coupling products of o- and p-aminophenols and their primary oxidation products. Heterogeneous reactions of aminophenol were also conducted using Arizona Test Dust (AZTD) under simulated aging conditions, and showed clear changes to optical properties, morphology, mixing state, and chemical composition. These results highlight the important role of iron redox chemistry in BrC formation under atmospherically relevant conditions.
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Affiliation(s)
- Hind A. Al-Abadleh
- grid.268252.90000 0001 1958 9263Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, ON N2L 3C5 Canada
| | - Fatemeh Motaghedi
- grid.268252.90000 0001 1958 9263Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, ON N2L 3C5 Canada
| | - Wisam Mohammed
- grid.268252.90000 0001 1958 9263Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, ON N2L 3C5 Canada
| | - Md Sohel Rana
- grid.266539.d0000 0004 1936 8438Department of Chemistry, University of Kentucky, Kentucky, 40506 USA
| | - Kotiba A. Malek
- grid.164295.d0000 0001 0941 7177Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742 USA
| | - Dewansh Rastogi
- grid.164295.d0000 0001 0941 7177Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742 USA
| | - Akua A. Asa-Awuku
- grid.164295.d0000 0001 0941 7177Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742 USA
| | - Marcelo I. Guzman
- grid.266539.d0000 0004 1936 8438Department of Chemistry, University of Kentucky, Kentucky, 40506 USA
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Liu L, Lin Q, Liang Z, Du R, Zhang G, Zhu Y, Qi B, Zhou S, Li W. Variations in concentration and solubility of iron in atmospheric fine particles during the COVID-19 pandemic: An example from China. GONDWANA RESEARCH : INTERNATIONAL GEOSCIENCE JOURNAL 2021; 97:138-144. [PMID: 35721257 PMCID: PMC9188026 DOI: 10.1016/j.gr.2021.05.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/11/2021] [Accepted: 05/16/2021] [Indexed: 05/09/2023]
Abstract
Iron (Fe) in the atmosphere can affect atmospheric chemical processes and human health. When deposited into oceans, it can further influence phytoplankton growth. These roles of Fe fundamentally depend on its concentration and solubility. However, the sources of aerosol Fe and controlling factors of Fe solubility in megacities remain poorly understood. The outbreak of the COVID-19 pandemic causes large changes in human activities, which provides a unique opportunity to answer these key issues. Field observations were conducted before, during, and after the COVID-19 lockdown in Hangzhou, China. Our results show that in the COVID-19 lockdown stage, the concentrations of total Fe (FeT, 75.0 ng m-3) and soluble Fe (FeS, 5.1 ng m-3) in PM2.5 decreased by 78% and 62%, respectively, compared with those (FeT 344.7 ng m-3, FeS 13.5 ng m-3) in the pre-lockdown stage. The sharp reduction (81%) in on-road vehicles was most responsible for the aerosol Fe decrease. Surprisingly, the Fe solubility increased by a factor of 1.9, from 4.2% in the pre-lockdown stage to 7.8% in the COVID-19 lockdown stage. We found that the atmospheric oxidizing capacity was enhanced after lockdown restrictions were implemented, which promoted the formation of more acidic species and further enhanced the dissolution of aerosol Fe.
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Affiliation(s)
- Lei Liu
- Department of Atmospheric Sciences, School of Earth Sciences, Zhejiang University, Hangzhou 310027, China
| | - Qiuhan Lin
- Department of Atmospheric Sciences, School of Earth Sciences, Zhejiang University, Hangzhou 310027, China
| | - Zhuoran Liang
- Key Laboratory of Cities' Mitigation and Adaptation to Climate Change in Shanghai (CMACC), Shanghai 200092, China
| | - Rongguang Du
- Hangzhou Meteorological Bureau, Hangzhou 310051, China
- Key Laboratory of Atmospheric Chemistry, China Meteorological Administration, Beijing 100081, China
| | | | - Yanhong Zhu
- Department of Atmospheric Sciences, School of Earth Sciences, Zhejiang University, Hangzhou 310027, China
| | - Bing Qi
- Department of Atmospheric Sciences, School of Earth Sciences, Zhejiang University, Hangzhou 310027, China
| | - Shengzhen Zhou
- School of Atmospheric Sciences and Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University, Guangzhou 510275, China
| | - Weijun Li
- Department of Atmospheric Sciences, School of Earth Sciences, Zhejiang University, Hangzhou 310027, China
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9
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Ling J, Zheng S, Sheng F, Wu H, Chen Z, Gu C, Jin X. Effect of common inorganic anions on iron-catalyzed secondary brown carbon formation from guaiacol. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 770:145206. [PMID: 33736418 DOI: 10.1016/j.scitotenv.2021.145206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 01/11/2021] [Accepted: 01/11/2021] [Indexed: 06/12/2023]
Abstract
Brown carbon (BrC) is the important component of aerosol with strong UV-visible absorbance. However, the formation of BrC is still elusive. Inorganic anions, e.g., Cl-, NO3- and SO42-, exist ubiquitously in the atmosphere, while their effects on the formation of BrC are poorly understood. In this study, we have systematically investigated the effects of pH (1, 2 and 3), inorganic anion (Cl-, NO3- and SO42-) and ionic strength (0.1, 0.5 and 1.0 M) on BrC generation process by measuring the optical, aggregation and product properties. Our results clearly show that the three factors strongly affect the BrC formation by influencing the oxidation activity and the complexation capability of different Fe(III) species. Marcus theory was used in this research to calculate the oxidation activity of different Fe(III) species. Among all the species of Fe(III), FeOH2+ is the most reactive form in the BrC formation reaction. Furthermore, the aggregation process of BrC was also studied, which is affected by different anions due to their different concentration and hydrability, and SO42- exhibits the highest efficiency to induce the aggregation of BrC. This study will deepen our understanding about the natural formation of BrC under environmentally relevant conditions, and be beneficial for controlling the production of atmospheric particulates and the subsequent health effects.
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Affiliation(s)
- Jingyi Ling
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Siheng Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Feng Sheng
- State Environmental Protection Key Laboratory of Soil Environmental Management and Pollution Control, Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, PR China
| | - Hao Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Zhanghao Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Cheng Gu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China
| | - Xin Jin
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
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