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Bikkina P, Bikkina S, Kawamura K, Sarma VVSS, Deshmukh DK. Unraveling the sources of atmospheric organic aerosols over the Arabian Sea: Insights from the stable carbon and nitrogen isotopic composition. Sci Total Environ 2022; 827:154260. [PMID: 35248629 DOI: 10.1016/j.scitotenv.2022.154260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 02/25/2022] [Accepted: 02/27/2022] [Indexed: 06/14/2023]
Abstract
The isotopic composition of stable carbon (δ13C) and nitrogen (δ15N) in marine aerosols influenced by the continental outflows are useful proxies for understanding the aging and secondary formation processes. Every winter, the haze pollutants transported from South Asia significantly affect the chemical composition of marine atmospheric boundary layer of the Arabian Sea. Here, we assessed the δ13C of total carbon (TC) and δ15N of total nitrogen (TN) in marine aerosols collected over the Arabian Sea during a winter cruise (6-24 December 2018). TC (2.1-13.4 μg m-3) is strongly correlated with TN (0.9-5.0 μg m-3), likely because of their common source-emissions, biomass burning and fossil-fuel combustion in the Indo-Gangetic Plain and South Asia (corroborated by backward-air mass trajectories and satellite fire counts). Besides, the linear relationship between the mass ratios of water-soluble organic carbon (WSOC) to TC (0.04-0.65) and δ13CTC (-25.1‰ to -22.9‰) underscores the importance of aging process. This means oxidation of organic aerosols during transport not only influences the WSOC levels but also affects their δ13CTC. Likewise, the prevalent inverse linear relationship between the equivalent mass ratio of (NH4+/non-sea-salt- or nss-SO42-) and δ15NTN (+15.3‰ to +25.1‰) emphasizes the overall significance of neutralization reactions between major acidic ([nss-SO42-] ≫ [NO3-]) and alkaline species (NH4+) in aerosols. Higher δ15NTN values in winter than the spring inter-monsoon clearly emphasizes the significance of the anthropogenic combustion sources (i.e., biomass burning) in the South Asian outflow. A comparison of δ13CTC and δ15NTN with the source emissions revealed that crop-residue burning emissions followed by the coal fired power plants mostly dictate the atmospheric abundance of organic aerosols in the wider South Asian outflow.
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Affiliation(s)
- Poonam Bikkina
- CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004, India.
| | - Srinivas Bikkina
- CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004, India; Chubu Institute of Advanced Sciences, Chubu University, Kasugai-shi, Aichi 4878501, Japan
| | - Kimitaka Kawamura
- Chubu Institute of Advanced Sciences, Chubu University, Kasugai-shi, Aichi 4878501, Japan
| | - V V S S Sarma
- CSIR-National Institute of Oceanography, Regional Cente Waltair, Visakhapatnam 530017, India
| | - Dhananjay K Deshmukh
- Chubu Institute of Advanced Sciences, Chubu University, Kasugai-shi, Aichi 4878501, Japan
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Rastogi N, Agnihotri R, Sawlani R, Patel A, Babu SS, Satish R. Chemical and isotopic characteristics of PM 10 over the Bay of Bengal: Effects of continental outflow on a marine environment. Sci Total Environ 2020; 726:138438. [PMID: 32344250 DOI: 10.1016/j.scitotenv.2020.138438] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/02/2020] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
Pollutants transport from South and Southeast Asia can profoundly affect the marine atmospheric boundary layer (MABL) over the Bay of Bengal (BoB). This study presents chemical and stable isotopic composition of PM10 collected at Port Blair Island (11.6°N, 92.7°E) located in the middle of the BoB during the late northeast monsoon (February-April), a period when the BoB receives considerable continental outflow. These samples (n = 50) were analysed for major ions, carbonaceous species, trace metals, and isotopic composition of total C, N, and S components. Mass concentration of PM10 ranged from 24 to 65 μg m-3 during the study period. The dominance of continental inputs over a marine realm was evident by a significant amount of non-sea-salt (nss)-SO42- (range: 1.8 to 16.9 μg m-3), which accounts for ~65% of the total water-soluble inorganic constituents. The impact of anthropogenic emissions was further evident from the widespread depletion of chloride (range: 57-100%, avg.: 98 ± 7%) from sea-salt aerosols. Carbonaceous species (elemental carbon and organic matter) contributed nearly 35% to PM10. Further, average δ13C (-25.6‰ ± 0.5) and δ34S (4.5‰ ± 1.3) values observed over the marine study region were similar to those found in typical urban environments. δ15N values (13.7‰ ± 5.1) show the significant presence of combustion sources along with the effect of atmospheric processing. Aerosol δ13C values correlate positively with the ratio of water-soluble organic carbon to total organic carbon, indicating the aging of organic aerosols during the transport. Chemical and isotopic data suggest that both biomass burning (BB) and fossil fuel burning (FFB) contributed to ambient PM10 with relatively more contribution of BB during February to early March and that of FFB during late March to middle of April. In aggregate, this study provides newer insights into sources of carbonaceous species and their chemical processing in MABL of BoB.
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Affiliation(s)
| | - Rajesh Agnihotri
- CSIR-National Physical Laboratory, New Delhi, India; Birbal Sahni Institute of Palaeosciences, Lucknow, India
| | - Ravi Sawlani
- CSIR-National Physical Laboratory, New Delhi, India
| | - Anil Patel
- Physical Research Laboratory, Ahmedabad, India
| | - S Suresh Babu
- Vikram Sarabhai Space Centre, Thiruvananthapuram, India
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Song J, Zhang Y, Zhang Y, Yuan Q, Zhao Y, Wang X, Zou S, Xu W, Lai S. A case study on the characterization of non-methane hydrocarbons over the South China Sea: Implication of land-sea air exchange. Sci Total Environ 2020; 717:134754. [PMID: 31837869 DOI: 10.1016/j.scitotenv.2019.134754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/07/2019] [Accepted: 09/29/2019] [Indexed: 06/10/2023]
Abstract
We present the characteristics of non-methane hydrocarbons (NMHCs) over the northern South China Sea (SCS) during a cruise campaign from September to October 2013. The mixing ratios of the total NMHCs ranged from 1.45 to 7.13 ppbv with an average of 3.54 ± 1.81 ppbv. Among the measured NMHCs, alkanes and aromatics were the major groups, accounting for 45.8 ± 8.7% and 28.7 ± 12.3% of the total NMHCs, respectively. Correlations of NMHCs with typical source tracers suggest that light alkanes and benzene were largely contributed by vehicular exhaust via long-range transport, while the other aromatics might be related to industrial sources and marine ship emissions. The spatial variations of NMHCs were observed with higher mixing ratios of NMHCs in the samples collected in the offshore areas than those in the coastal areas. Air mass back-trajectory analysis and diagnostic ratios of NMHCs show that the elevations of the total NMHCs were caused by the regional pollution transport from the southeast coast of China and/or southern China. The ozone formation potentials (OFPs) of NMHCs were calculated and the results show that the aromatics associated with marine ship emissions were the important contributors to the total OFP. This study provides useful information on the interaction between continental outflow and marine atmosphere.
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Affiliation(s)
- Junwei Song
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, and Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Yingyi Zhang
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, and Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
| | - Yanli Zhang
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
| | - Qi Yuan
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, and Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Yan Zhao
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, and Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; Guangdong Environmental Monitoring Center, Guangzhou, China
| | - Xinming Wang
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
| | - Shichun Zou
- School of Marine Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Weihai Xu
- Key Laboratory of Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Senchao Lai
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, and Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
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