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You B, Zhang Z, Du A, Li Y, Sun J, Li Z, Chen C, Zhou W, Xu W, Lei L, Fu P, Hou S, Li P, Sun Y. Seasonal characterization of chemical and optical properties of water-soluble organic aerosol in Beijing. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 930:172508. [PMID: 38642752 DOI: 10.1016/j.scitotenv.2024.172508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/13/2024] [Accepted: 04/13/2024] [Indexed: 04/22/2024]
Abstract
Water-soluble organic aerosol (WSOA) plays a crucial role in altering radiative forcing and impacting human health. However, our understanding of the seasonal variations of WSOA in Chinese megacities after the three-year clean air action plan is limited. In this study, we analyzed PM2.5 filter samples collected over one year (2020-2021) in Beijing to characterize the seasonal changes in the chemical and optical properties of WSOA using an offline aerosol mass spectrometer along with spectroscopy techniques. The mean mass concentration of WSOA during the observation period was 8.84 ± 7.12 μg m-3, constituting approximately 64-67 % of OA. Our results indicate the contribution of secondary OA (SOA) increased by 13-28 % due to a substantial reduction in primary emissions after the clean air action plan. The composition of WSOA exhibited pronounced seasonal variations, with a predominant contribution from less oxidized SOA in summer (61 %) and primary OA originating from coal combustion and biomass burning during the heating season (34 %). The mass absorption efficiency of WSOA at 365 nm in winter was nearly twice that in summer, suggesting that WSOA from primary emissions possesses a stronger light-absorbing capability than SOA. On average, water-soluble brown carbon accounted for 33-48 % of total brown carbon absorption. Fluorescence analysis revealed humic-like substances as the most significant fluorescence component of WSOA, constituting 82 %. Furthermore, both absorption and fluorescence chromophores were associated with nitrogen-containing compounds, highlighting the role of nitrogen-containing species in influencing the optical properties of WSOA. The results are important for chemical transport models to accurately simulate the WSOA and its climate effects.
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Affiliation(s)
- Bo You
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiqiang Zhang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Aodong Du
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Li
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiaxing Sun
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhijie Li
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chun Chen
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Zhou
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Weiqi Xu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Lu Lei
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Pingqing Fu
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China
| | - Shengjie Hou
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ping Li
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Yele Sun
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
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Chakraborty A, Gupta T, Mandaria A, Tripathi S. Trace elements in ambient aerosols and size-resolved fog droplets: Trends, enrichment, and risk assessment. Heliyon 2023; 9:e16400. [PMID: 37260893 PMCID: PMC10227332 DOI: 10.1016/j.heliyon.2023.e16400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 05/05/2023] [Accepted: 05/15/2023] [Indexed: 06/02/2023] Open
Abstract
Ambient particulate matter (PM) is composed of inorganic and organic components. The contribution of each component is impacted by various factors such as emission sources, atmospheric aging process, and size of the PM or droplets. This study mainly focuses on the effect of the PM and droplet size on trace elemental concentrations, for which various size fractions of ambient PM (PM1, PM2.5) were collected on quartz filters along with fog water (FW) samples during winter. Simultaneous, online measurements of the mass concentrations of PM1 and PM2.5 were also carried out. At the time of the collection, the mass concentration of PM2.5 ranged from 19 to 890 μg/m3, and its mean value was 227 μg/m3. During the sampling period, 17 fog events occurred and caused a 27% reduction in the mean pre-fog PM2.5 concentration. All the PM and FW samples were analyzed for 12 trace elements: Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Zn, V. The concentrations of the various trace elements in the PM1, PM2.5, and FW samples encompassed a wide range: 10 (V)-2432 (Na) ng/m3, 34 (Mn)-13810 (Na) ng/m3, and 8 (Cr)-19870 (Ca) μg/l, respectively. The concentrations of the trace elements in the FW samples indicated a droplet-size-dependent trend: the small droplets (diameter <16 μm) had several times (3-10 times) higher concentrations than the coarser droplets (diameter >22 μm). The enrichment factor (EF) analysis revealed that the EF values for almost all the trace elements were an order of magnitude higher in the FW samples than in PM1 and PM2.5. Risk assessment based on toxic elements suggested a very high inhalation carcinogenic risk (231 per million) for the exposed population during foggy periods. This study will facilitate decision-making by policymakers regarding air quality and health concerns.
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Affiliation(s)
- Abhishek Chakraborty
- Department of Environmental Science and Engineering (ESED), Indian Institute of Technology Bombay, Mumbai, India
| | - Tarun Gupta
- Department of Civil Engineering, Indian Institute of Technology, Kanpur, India
- Centre of Environmental Science and Engineering, CESE, IIT, Kanpur, India
| | - Anil Mandaria
- Department of Civil Engineering, Indian Institute of Technology, Kanpur, India
- Centre of Environmental Science and Engineering, CESE, IIT, Kanpur, India
| | - Shruti Tripathi
- Department of Environmental Science and Engineering (ESED), Indian Institute of Technology Bombay, Mumbai, India
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Gupta T, Rajeev P, Rajput R. Emerging Major Role of Organic Aerosols in Explaining the Occurrence, Frequency, and Magnitude of Haze and Fog Episodes during Wintertime in the Indo Gangetic Plain. ACS OMEGA 2022; 7:1575-1584. [PMID: 35071853 PMCID: PMC8771687 DOI: 10.1021/acsomega.1c05467] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 12/21/2021] [Indexed: 06/02/2023]
Abstract
Aerosols are an important part of Earth's atmosphere. They can absorb, scatter, or reflect the incoming solar radiation, which results in heating or cooling of Earth, thus impacting its climate. It affects the health of exposed human population adversely, reduces visibility, disturbs environmental systems, and causes material damage. This study summarizes the research carried out to understand the role of aerosol load and its physicochemical characteristics on occurrence, frequency, and magnitude of haze and fog events during wintertime within the Indo Gangetic Plain (IGP) in the past decade. For most species, the highest concentration was measured during foggy events at night-time over the winter season. A few species such as water-soluble organic and inorganic carbon (WSOC and WSIC), K+, SO4 2-, and NO3 -, owing to their hygroscopic nature, were efficiently scavenged, resulting in their lower concentration within the interstitial aerosol during fog episodes. Oligomerization with hydroxy and carbonyl functional groups during AFP (activating fog period) and DFP (dissipating fog period), respectively, accompanied by acidic aerosol (having catalytic ability) and high aerosol liquid water content conditions was found to be significant. Whereas the fragmentation process was dominant along with functionalization of -RCOOH or carbonyl (aldehyde/ketone) and -RCOOH moieties during FP (fog period) and PoFP (post-fog period), respectively. Transition metals play an important role in aqueous production of secondary organic aerosol (SOA) especially during the night-time. Crustal sources had the highest scavenging efficiency along with WSOC playing an important role in nucleation scavenging. Fine droplets had a higher concentration of species with a larger fraction of highly oxidized organic matter (OM) as compared to coarse or medium size droplets. Also, a new approach to calculate absorption by black carbon (BC) and brown carbon (BrC) was proposed, which found the water-soluble brown carbon (WSBrC) absorption value in aerosol to be up to 1.8 times higher than that measured in their corresponding aqueous extracts. Organic aerosol plays a vital role in facilitating fog formation and is responsible for the longer residence time in the ambient atmosphere. Ammonia plays an important role in stabilizing organic aerosol and aids to this recurring haze-fog-haze cycle that is dominant during wintertime in the IGP. Therefore, controlling the major anthropogenic sources of organic aerosol and ammonia should be our top priority in this part of the world.
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Choudhary V, Rajput P, Gupta T. Absorption properties and forcing efficiency of light-absorbing water-soluble organic aerosols: Seasonal and spatial variability. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 272:115932. [PMID: 33248827 DOI: 10.1016/j.envpol.2020.115932] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 10/25/2020] [Accepted: 10/26/2020] [Indexed: 06/12/2023]
Abstract
Light-absorbing organic aerosols, also known as brown carbon (BrC), enhance the warming effect of the Earth's atmosphere. The seasonal and spatial variability of BrC absorption properties is poorly constrained and accounted for in the climate models resulting in a substantial underestimation of their radiative forcing estimates. This study reports seasonal and spatial variability of absorption properties and simple forcing efficiency of light-absorbing water-soluble organic carbon (WSOC, SFEWSOC) by utilizing current and previous field-based measurements reported mostly from Asia along with a few observations from Europe, the USA, and the Amazon rainforest. The absorption coefficient of WSOC at 365 nm (babs-365) and the concentrations of carbonaceous species at Kanpur were about an order of magnitude higher during winter than in the monsoon season owing to differences in the boundary layer height, active sources and their strengths, and amount of seasonal wet precipitation. The WSOC aerosols during winter exhibited ∼1.6 times higher light absorption capacity than in the monsoon season at Kanpur site. The assessment of spatial variability of the imaginary component of the refractive index spectrum (kλ) across South Asia has revealed that it varies from ∼1 to 2 orders of magnitude and light absorption capacity of WSOC ranges from 3 to 21 W/g. The light absorption capacity of WSOC aerosols exhibited less spatial variability across East Asia (5-13 W/g) when compared to that in the South Asia. The photochemical aging of WSOC aerosols, indicated by the enhancement in WSOC/OC ratio, was linked to degradation in their light absorption capacity, whereas the absorption Ångström exponent (AAE) remained unaffected. This study recommends the adoption of refined climate models where sampling regime specific absorption properties are calculated separately, such that these inputs can better constrain the model estimates of the global effects of BrC.
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Affiliation(s)
- Vikram Choudhary
- Department of Civil Engineering and APTL at Center for Environmental Science and Engineering (CESE), Indian Institute of Technology Kanpur, Kanpur, 208 016, India.
| | - Prashant Rajput
- Centre for Environmental Health (CEH), Public Health Foundation of India, Gurugram, Haryana, 122002, India
| | - Tarun Gupta
- Department of Civil Engineering and APTL at Center for Environmental Science and Engineering (CESE), Indian Institute of Technology Kanpur, Kanpur, 208 016, India
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Mukherjee A, Dey S, Rana A, Jia S, Banerjee S, Sarkar S. Sources and atmospheric processing of brown carbon and HULIS in the Indo-Gangetic Plain: Insights from compositional analysis. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 267:115440. [PMID: 32858437 DOI: 10.1016/j.envpol.2020.115440] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/11/2020] [Accepted: 08/14/2020] [Indexed: 06/11/2023]
Abstract
We present here spectroscopic compositional analysis of brown carbon (BrC) and humic-like substances (HULIS) in the Indian context under varying conditions of source emissions and atmospheric processing. To this end, we study bulk water-soluble organic matter (WSOM), neutral- and acidic-HULIS (HULIS-n and HULIS-a), and high-polarity (HP)-WSOM collected in the eastern Indo-Gangetic Plain (IGP) with respect to UV-Vis, fluorescence, FT-IR, 1H NMR and 13C characteristics under three aerosol regimes: photochemistry-dominated summer, aged biomass burning (BB)-dominated post-monsoon, and fresh BB-dominated winter. Absorption coefficients (babs_365 nm; Mm-1) of WSOM and HULIS fractions increase by a factor of 2-9 during winter as compared to summer, with HULIS-n dominating total HULIS + HP-WSOM absorption (73-81%). Fluorophores in HULIS-n appear to contain near-similar levels of aromatic and unsaturated aliphatic conjugation across seasons, while HULIS-a exhibits distinctively smaller-chain structures in summer and post-monsoon. FT-IR spectra reveals, among others, strong signatures of aromatic phenols in winter WSOM suggesting a BB-related origin. 1H NMR-based source attribution coupled with back trajectory analysis indicate the presence of secondary and BB-related organic aerosol (SOA and BBOA) in the post-monsoon and winter, and marine-derived OA (MOA) in the summer, which is supported by 13C measurements. Overall, these observations uncover a complex interplay of emissions and atmospheric processing of carbonaceous aerosols in the IGP.
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Affiliation(s)
- Arya Mukherjee
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, 741246, Nadia, India
| | - Supriya Dey
- Department of Earth Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, 741246, Nadia, India
| | - Archita Rana
- Department of Earth Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, 741246, Nadia, India
| | - Shiguo Jia
- Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University, Guangzhou, 510275, PR China; School of Atmospheric Sciences, Sun Yat-sen University, Guangzhou, 510275, PR China
| | - Supratim Banerjee
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, 741246, Nadia, India
| | - Sayantan Sarkar
- Department of Earth Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, 741246, Nadia, India; School of Engineering, Indian Institute of Technology (IIT) Mandi, Kamand, Himachal Pradesh, 175075, India.
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Liakakou E, Kaskaoutis DG, Grivas G, Stavroulas I, Tsagkaraki M, Paraskevopoulou D, Bougiatioti A, Dumka UC, Gerasopoulos E, Mihalopoulos N. Long-term brown carbon spectral characteristics in a Mediterranean city (Athens). THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 708:135019. [PMID: 31791764 DOI: 10.1016/j.scitotenv.2019.135019] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/02/2019] [Accepted: 10/15/2019] [Indexed: 05/19/2023]
Abstract
This study analyses 4-years of continuous 7-λ Aethalometer (AE-33) measurements in an urban-background environment of Athens, to resolve the spectral absorption coefficients (babs) for black carbon (BC) and brown carbon (BrC). An important BrC contribution (23.7 ± 11.6%) to the total babs at 370 nm is estimated for the period May 2015-April 2019, characterized by a remarkable seasonality with winter maximum (33.5 ± 13.6%) and summer minimum (18.5 ± 8.1%), while at longer wavelengths the BrC contribution is significantly reduced (6.8 ± 3.6% at 660 nm). The wavelength dependence of the total babs gives an annual-mean AAE370-880 of 1.31, with higher values in winter night-time. The BrC absorption and its contribution to babs presents a large increase reaching up to 39.1 ± 13.6% during winter nights (370 nm), suggesting residential wood burning (RWB) emissions as a dominant source for BrC. This is supported by strong correlations of the BrC absorption with OC, EC, the fragment ion m/z 60 derived from ACSM and PMF-analyzed organic fractions related to biomass burning (e.g. BBOA). In contrast, BrC absorption decreases significantly during daytime as well as in the warm period, reaching to a minimum during the early-afternoon hours in all seasons due to photo-chemical degradation. Estimated secondary BrC absorption is practically evident only during winter night-time, implying the fast oxidation of BrC species from RWB emissions. Changes in mixing-layer height do not significantly affect the BrC absorption in winter, while they play a major role in summer.
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Affiliation(s)
- E Liakakou
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece.
| | - D G Kaskaoutis
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece
| | - G Grivas
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece
| | - I Stavroulas
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece
| | - M Tsagkaraki
- Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, 71003 Crete, Greece
| | - D Paraskevopoulou
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece
| | - A Bougiatioti
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece
| | - U C Dumka
- Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital 263 001, India
| | - E Gerasopoulos
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece
| | - N Mihalopoulos
- Institute for Environmental Research and Sustainable Development, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece; Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, 71003 Crete, Greece.
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Bikkina S, Sarin M. Brown carbon in the continental outflow to the North Indian Ocean. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:970-987. [PMID: 31089643 DOI: 10.1039/c9em00089e] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this paper, we synthesize the size distribution and optical properties of the atmospheric water-soluble fraction of light-absorbing organic carbon (brown carbon; BrC) in the continental outflow from the Indo-Gangetic Plain (IGP) in South Asia to the North Indian Ocean. A comparison of the mass absorption coefficient of water-soluble BrC (babs-WSBrC-365nm) in PM2.5 with that in PM10 sampled over the Bay of Bengal reveals the dominance of BrC in fine mode. Furthermore, the babs-BrC-365nm shows a significant linear relationship with mass concentrations of airborne particulate matter, water-soluble organic carbon and non-sea-salt-K+ in the continental outflow from the IGP. This observation emphasizes the ubiquitous nature and significant contribution of water-soluble BrC from biomass burning emissions (BBEs). Comparing the absorption properties from this study with global datasets, it is discernible that BBEs dominate BrC absorption. Furthermore, the imaginary refractive index of water-soluble BrC (kWSBrC-365nm) in marine aerosols sampled over the North Indian Ocean during November is significantly higher than during December to January. Thus, significant temporal variability is associated with crop-residue burning emissions in the IGP on the composition of BrC over the North Indian Ocean. Our estimates show that the babs-WSBrC-365nm and kWSBrC-365nm from post-harvest crop-residue burning emissions in the IGP are much higher than the BBEs from the southeastern United States and Amazonian forest fires. Another major finding of this study is the lack of significant relationship between kWSBrC-365nm and the mass ratio of elemental carbon to particulate organic matter, as previously suggested by chamber experiments to model varying BrC absorption properties in ambient aerosols. Therefore, considerable spatio-temporal variability prevails among emission sources (wood burning vs. crop-residue burning), which needs to be considered when assessing the regional radiative forcing of BrC relative to major absorbing elemental carbon.
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Affiliation(s)
- Srinivas Bikkina
- Geosciences Division, Physical Research Laboratory, Ahmedabad-380 009, India.
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Sorathia F, Rajput P, Gupta T. Dicarboxylic acids and levoglucosan in aerosols from Indo-Gangetic Plain: Inferences from day night variability during wintertime. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 624:451-460. [PMID: 29268217 DOI: 10.1016/j.scitotenv.2017.12.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 12/11/2017] [Accepted: 12/11/2017] [Indexed: 06/07/2023]
Abstract
This study assesses daytime and nighttime atmospheric abundance and molecular distribution of dicarboxylic acids (DCA: C2-C10) and biomass burning tracers (levoglucosan and biomass burning derived potassium: K+BB) in PM10 (particulate matter with aerodynamic diameter≤10μm) from an urban location, Kanpur (in central Indo-Gangetic Plain: IGP) during wintertime (December 2015-February 2016). In this study, PM10 varied from 130 to 242 and 175-388μgm-3 during daytime and nighttime, respectively. The average ratios of OC/EC (day: 12.3; night: 9.3) and WSOC/OC (day: 0.74; night: 0.48) were relatively high during daytime (OC: organic carbon; EC: elemental carbon; WSOC: water-soluble organic carbon). Strong linear correlations (R2≥0.6; p<0.05) of OC with levoglucosan and K+BB suggest biomass burning emission as predominant source of organic aerosols over the IGP. The measured concentrations of total DCA (ΣC2-C10) showed pronounced diurnal variability with a higher concentration during nighttime (2510±1025ngm-3) as compared to that in daytime (1499±562ngm-3). Concentrations of oxalic acid (C2), succinic acid (C4) and malonic acid (C3) were predominantly high as compared to other congeners of DCA (C2-C10) over central IGP. Relatively higher mass fraction (73.4%) of C2 in total DCA during nighttime than that in daytime (61.5%) indicates role of secondary organic aerosols (SOAs) formation involving aqueous-phase chemistry. Strong linear correlations of C2 with C3 and C4 plausibly suggest that C2 can have predominant formation pathways via decomposition of higher congeners of DCA. Overall, strong linear correlations of C2 with levoglucosan and sulphate suggest that biomass burning emission and secondary transformations are predominant sources of DCA over IGP during wintertime.
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Affiliation(s)
- Fena Sorathia
- Atmospheric Particle Technology Lab at Centre for Environmental Science and Engineering and Department of Civil Engineering, Indian Institute of Technology Kanpur, 208016, India
| | - Prashant Rajput
- Atmospheric Particle Technology Lab at Centre for Environmental Science and Engineering and Department of Civil Engineering, Indian Institute of Technology Kanpur, 208016, India; Global Centre for Clean Air Research (GCARE) and Department of Civil and Environmental Engineering, University of Surrey, Guildford - GU2 7XH, UK
| | - Tarun Gupta
- Atmospheric Particle Technology Lab at Centre for Environmental Science and Engineering and Department of Civil Engineering, Indian Institute of Technology Kanpur, 208016, India.
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Kaushal D, Kumar A, Yadav S, Tandon A, Attri AK. Wintertime carbonaceous aerosols over Dhauladhar region of North-Western Himalayas. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:8044-8056. [PMID: 29305806 DOI: 10.1007/s11356-017-1060-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 12/14/2017] [Indexed: 05/10/2023]
Abstract
Carbonaceous aerosols play an important role in affecting human health, radiative forcing, hydrological cycle, and climate change. As our current understanding about the carbonaceous aerosols, the source(s) and process(es) associated with them in the ecologically sensitive North-Western Himalayas are limited; this systematic study was planned to understand inherent dynamics in the mass concentration and source contribution of carbonaceous aerosols in the Dhauladhar region. During four winter months (January 2015-April 2015), 24-h PM10 samples were collected every week simultaneously at the rural site of Pohara (32.19° N, 76.20° E; 750 m amsl) and the urban location of Dharamshala (32.20° N, 76.32° E; 1350 m amsl). These samples were analyzed by using thermal/optical carbon analyzer for different carbon forms. Organic carbon (OC) dominated over elemental carbon (EC) and was found to be 59.3 and 64.1% in total carbon (TC) at Pohara and Dharamshala, respectively. The respective mass concentrations of OC and EC were higher at Pohara (6.8 ± 2.3 and 4.8 ± 2.0 μg.m-3) in comparison to that observed in Dharamshala (5.0 ± 3.1 and 2.5 ± 0.6 μg.m-3). The OC/EC ratio at Pohara (1.51 ± 0.41) indicates the dominance of fossil fuel combustion (coal and vehicular exhaust), while at Dharamshala, an OC/EC of 2.01 ± 1.07 signified additional contribution from secondary organic carbon (SOC). Diagnostic ratios (OC/EC and char-EC/soot-EC) suggested dominance of emissions from fossil fuel combustion sources over biomass burning sources in the region. Estimated non-sea salt (nss)K+/OC and nssK+/EC ratios indicated heterogeneity within the biomass burning sources over low and high altitude locations. A strong correlation between nssK+ and SOC over a high altitude urban location further suggested possible conversion of gaseous precursors to carbonaceous particles during coniferous wood burning.
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Affiliation(s)
- Deepika Kaushal
- School of Earth and Environmental Sciences, Central University of Himachal Pradesh, Dharamshala, Kangra, H.P., 176215, India
| | - Ajay Kumar
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Shweta Yadav
- Department of Environmental Sciences, Central University of Jammu, Bagla, Rahya Suchani, Samba, Jammu, J&K, 181143, India
| | - Ankit Tandon
- School of Earth and Environmental Sciences, Central University of Himachal Pradesh, Dharamshala, Kangra, H.P., 176215, India.
| | - Arun K Attri
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
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Rajput P, Singh DK, Singh AK, Gupta T. Chemical composition and source-apportionment of sub-micron particles during wintertime over Northern India: New insights on influence of fog-processing. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 233:81-91. [PMID: 29055838 DOI: 10.1016/j.envpol.2017.10.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 09/25/2017] [Accepted: 10/09/2017] [Indexed: 06/07/2023]
Abstract
A comprehensive study was carried out from central part of Indo-Gangetic Plain (IGP; at Kanpur) to understand abundance, temporal variability, processes (secondary formation and fog-processing) and source-apportionment of PM1-bound species (PM1: particulate matter of aerodynamic diameter ≤ 1.0 μm) during wintertime. A total of 50 PM1 samples were collected of which 33 samples represent submicron aerosol characteristics under non-foggy condition whereas 17 samples represent characteristics under thick foggy condition. PM1 mass concentration during non-foggy episodes varied from 24-393 (Avg.: 247) μg m-3, whereas during foggy condition it ranged from 42-243 (Avg.: 107) μg m-3. With respect to non-foggy condition, the foggy conditions were associated with higher contribution of PM1-bound organic matter (OM, by 23%). However, lower fractional contribution of SO42-, NO3- and NH4+ during foggy conditions is attributable to wet-scavenging owing to their high affinity to water. Significant influence of fog-processing on organic aerosols composition is also reflected by co-enhancement in OC/EC and WSOC/OC ratio during foggy condition. A reduction by 5% in mineral dust fraction under foggy condition is associated with a parallel decrease in PM1 mass concentration. However, mass fraction of elemental carbon (EC) looks quite similar (≈3% of PM1) but the mass absorption efficiency (MAE) of EC is higher by 30% during foggy episodes. Thus, it is evident from this study that fog-processing leads to quite significant enhancement in OM (23%) contribution (and MAE of EC) with nearly equal and parallel decrease in SO42-, NO3- and NH4+ and mineral dust fractions (totaling to 24%). Characteristic features of mineral dust remain similar under foggy and non-foggy conditions; inferred from similar ratios of Fe/Al (≈0.3), Ca/Al (0.35) and Mg/Al (0.22). Positive matrix factorization (PMF) resolves seven sources: biomass burning (19.4%), coal combustion (1.1%), vehicular emission (3%), industrial activities (6.1%), leather tanneries (4%), secondary transformations (46.2%) and mineral dust (20.2%).
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Affiliation(s)
- Prashant Rajput
- Department of Civil Engineering and APTL at Center for Environmental Science and Engineering (CESE), Indian Institute of Technology Kanpur, Kanpur, 208 016, India; Global Centre for Clean Air Research (GCARE), Department of Civil and Environmental Engineering, University of Surrey, Guildford, GU2 7XH, UK
| | - Dharmendra Kumar Singh
- Department of Civil Engineering and APTL at Center for Environmental Science and Engineering (CESE), Indian Institute of Technology Kanpur, Kanpur, 208 016, India; NUS Environmental Research Institute (NERI), National University of Singapore, #02-01, T-Lab Building 5A Engineering Drive 1, 117411, Singapore
| | - Amit Kumar Singh
- Department of Civil Engineering and APTL at Center for Environmental Science and Engineering (CESE), Indian Institute of Technology Kanpur, Kanpur, 208 016, India
| | - Tarun Gupta
- Department of Civil Engineering and APTL at Center for Environmental Science and Engineering (CESE), Indian Institute of Technology Kanpur, Kanpur, 208 016, India.
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Gupta T, Agarwal AK, Agarwal RA, Labhsetwar NK. Bioaerosols Over the Indo-Gangetic Plain: Influence of Biomass Burning Emission and Ambient Meteorology. ENVIRONMENTAL CONTAMINANTS 2017. [PMCID: PMC7123097 DOI: 10.1007/978-981-10-7332-8_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bioaerosols (particles of biological origin) can be produced from living or dead plants and animals. They can potentially serve as the cloud condensation and ice nuclei (CCN and IN). Their role in global carbon cycle further highlights importance of studying their variability to link up with climate relevance parameters. Focusing on tropical region reveals that it holds wealthy number of human population and has massive vegetation cover-area. From Indian region, production estimates of bioaerosols from human population (current: ~1.25 billion; of which over 45% resides in Indo-Gangetic Plain: IGP) and Wildlife Sanctuaries and National Parks (100 in numbers, situated from north to south and east to west) is not known. Most of the forest fires in India occur during March–June (hot and drier season). The detailed information on chemical composition, fingerprinting and radiative forcing from regional forest fires is also lacking. Unlike natural sources (forest cover and fires), the seasonal variability of pollutants emission characteristic and chemical, optical and radiative forcing are relatively well studied from anthropogenic biomass (post-harvest paddy- and wheat-residue and biofuels) burning emission in India. However, the abundance of bioaerosols and their variability over a large stretch of IGP (north-west to north-east) was not well documented. Towards this, we have undertaken a year-long campaign to study and document (first-attempt) bioaerosols variability over a complete annual cycle from central IGP. We observed a parallel enhancement in concentrations of fine-particulate matter (PM2.5 in October–November: 158 ± 89 µg m−3 as compared to June–September months: 40 ± 18 µg m−3; two-tailed t = 8.2, p < 0.05) and bioaerosols (particularly Gram-negative bacteria: GNB, a source of endotoxin in ambient air; 186 ± 87 CFU/m3 during October-November as compared to 114 ± 58 CFU/m3; t = 4.0, p < 0.05) with the biomass burning emissions intensification period. The abundance of bioaerosols exhibits influence of ambient meteorology, for example GNB exhibited negative correlations with T, wind speed and heavy (>4 mm daily) precipitation, whereas it showed positive correlations with RH and low precipitation amount (<4 mm). Studying bioaerosols and establishing its linkage to health and climate appear to be of utmost importance.
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Affiliation(s)
- Tarun Gupta
- Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh India
| | - Avinash Kumar Agarwal
- Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh India
| | - Rashmi Avinash Agarwal
- Department of Civil Engineering, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh India
| | - Nitin K. Labhsetwar
- Energy and Resource Management Division, CSIR-National Environmental Engineering Research Institute (NEERI), Nagpur, Maharashtra India
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