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Li L, Han Y, Li J, Lin Y, Zhang X, Wang Q, Cao J. Effects of photochemical aging on the molecular composition of organic aerosols derived from agricultural biomass burning in whole combustion process. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 946:174152. [PMID: 38906306 DOI: 10.1016/j.scitotenv.2024.174152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 06/04/2024] [Accepted: 06/18/2024] [Indexed: 06/23/2024]
Abstract
Biomass burning organic aerosols (BBOA) are key components of atmospheric particulate matter, yet the effects of aging process on their chemical composition and related properties remain poorly understood. In this study, fresh smoke emissions from the combustion of three types of agricultural biomass residues (rice, maize, and wheat straws) were photochemically aged in an oxidation flow reactor. The changes in BBOA composition were characterized by offline analysis using ultrahigh performance liquid chromatography coupled with Orbitrap mass spectrometry. The BBOA molecular composition varied dramatically with biomass type and aging process. Fresh and aged BBOA were predominated by CHO and nitrogen-containing CHON, CHN, and CHONS species, while with very few CHOS and other non‑oxygen species. The signal peak area variations revealed that individual molecular species underwent dynamic changes, with 77-81 % of fresh species decreased or even disappeared and 33-46 % of aged species being newly formed. A notable increase was observed in the number and peak area of CxHyO≥6 compounds in aged BBOA, suggesting that photochemical process served as an important source of highly oxygenated species. Heterocyclic CxHyN2 compounds mostly dominated in fresh CHN species, whereas CxHyN1 were more abundant in aged ones. Fragmentation and homologs oxidation by addition of oxygen-containing functional groups were important pathways for the BBOA aging. The changes in BBOA composition with aging would have large impacts on particle optical properties and toxicity. This study highlights the significance of photochemical aging process in altering chemical composition and related properties of BBOA.
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Affiliation(s)
- Lijuan Li
- 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
| | - 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.
| | - Jianjun Li
- 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
| | - Yue Lin
- 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; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Zhang
- 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; School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Qiyuan Wang
- 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
| | - Junji Cao
- 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; Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
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2
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Liao K, Cheng YY, Yea SS, Chen LWA, Seinfeld JH, Yu JZ. New Analytical Paradigm to Determine Concentration of Brown Carbon and Its Sample-by-Sample Mass Absorption Efficiency. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:17386-17395. [PMID: 39298651 DOI: 10.1021/acs.est.4c06831] [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: 09/22/2024]
Abstract
Brown carbon (BrC) has a substantial direct radiative effect, but current estimates of its impact on radiative balance are highly uncertain due to a lack of measurements of its light-absorbing properties, such as mass absorption efficiency (MAE). Here, we present a new analytical paradigm based on a Bayesian inference (BI) model that takes multiwavelength aethalometer measurements and total carbon data to resolve the concentrations of black carbon and BrC, and MAEs of BrC on a sample-by-sample basis. Hourly MAEs, unattainable in previous studies, can now be calculated, enabling the first-time observation of the darkening-bleaching dynamics of BrC in response to photochemical transformation. We demonstrate the application of this BI model to analyze measurements collected over one year (2021-2022) in Hong Kong. Diel variations in MAE370 nm of BrC reveal a darkening-to-bleaching transition occurring between 8 and 10 O'clock when the solar irradiance ranges from 30 to 400 W m-2. Furthermore, we consistently observe an increase in MAE370 nm of BrC with nitrogen oxide concentrations, suggesting the enhanced formation of nitrogenous organics. This BI model-based data analysis would bring forth a breakthrough in amassing observation data of BrC and its MAEs in diverse ambient environments and with high time resolution.
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Affiliation(s)
- Kezheng Liao
- Department of Chemistry, The Hong Kong University of Science and Technology, Kowloon, Hong Kong 999077, China
- Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Kowloon, Hong Kong 999077, China
| | - Yuk Ying Cheng
- Department of Chemistry, The Hong Kong University of Science and Technology, Kowloon, Hong Kong 999077, China
| | - Sui Shing Yea
- Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Kowloon, Hong Kong 999077, China
| | - L-W Antony Chen
- Department of Environmental and Occupational Health, School of Public Health, University of Nevada, Las Vegas, Las Vegas, Nevada 89154, United States
- Division of Atmospheric Sciences, Desert Research Institute, Reno, Nevada 89512, United States
| | - John H Seinfeld
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Jian Zhen Yu
- Department of Chemistry, The Hong Kong University of Science and Technology, Kowloon, Hong Kong 999077, China
- Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Kowloon, Hong Kong 999077, China
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3
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Holder AL, Sullivan AP. Emissions, Chemistry, and the Environmental Impacts of Wildland Fire. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024. [PMID: 39133033 DOI: 10.1021/acs.est.4c07631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
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4
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Katoch A, Abbass M, Chen YW, Ho TPT, Fan CF, Cheng YH. Applying the total carbon-black carbon approach method to investigate the characteristics of primary and secondary carbonaceous aerosols in ambient PM 2.5 in northern Taiwan. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 936:173476. [PMID: 38788950 DOI: 10.1016/j.scitotenv.2024.173476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 05/13/2024] [Accepted: 05/21/2024] [Indexed: 05/26/2024]
Abstract
Ambient fine particulate matter (PM2.5) comprises a diverse array of carbonaceous species, and the impact of carbonaceous aerosols (CA) extends to both long-term and short-term effects on human health and the environment. Understanding the distinctive composition of CA is crucial for gaining insights into the origins of airborne particulate matter. Due to their diverse physicochemical properties and intricate heterogeneous reactions, CA often exhibits temporal and spatial variations. Ground-based and highly time-resolved apportionment methods play a vital role in discerning CA emissions. This study utilized high-time resolution data of total carbon (TC) and black carbon (BC) for CA apportionment in northern Taiwan. The advanced numerical model (TC-BC(λ)), coupled with continuous measurement data, facilitated CA allocation based on optical absorption characteristics, organic or elemental carbon composition, and the distinction between primary and secondary origins. Primary carbonaceous aerosols dominated the monitoring site, accounting for 67.5 % compared to the 32.5 % contribution from secondary forms of CA. The summer season exhibited a maximum increase in secondary organic aerosols (SOA) at 41.5 %. Diurnal variations for primary emissions, such as BCc and primary organic aerosols (POA), showed marked peaks for BCff and POAnon-abs during morning rush hours. In contrast, BCbb and POABrC displayed bimodal peaks with increased concentrations during evening hours. Conversely, SOA exhibited significantly different diurnal trends, with SOABrC peaking late at night due to aqueous phased reactions and a noontime peak of SOAnon-abs observed due to photo-oxidation processes. Furthermore, the study employed backward trajectory analysis and concentration-weighted trajectories (CWTs) to examine the long-range transport of CA, identifying potential sources, origins, and transport patterns of CA components to the receptor site in Taiwan during different seasons.
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Affiliation(s)
- Ankita Katoch
- Center for Environmental Sustainability and Human Health, Ming Chi University of Technology, Taishan, New Taipei 243089, Taiwan
| | - Muneer Abbass
- Department of Safety, Health and Environmental Engineering, Ming Chi University of Technology, Taishan, New Taipei 243089, Taiwan
| | - Yi-Wen Chen
- Center for Environmental Sustainability and Human Health, Ming Chi University of Technology, Taishan, New Taipei 243089, Taiwan
| | - Thi Phuong Thao Ho
- Center for Environmental Sustainability and Human Health, Ming Chi University of Technology, Taishan, New Taipei 243089, Taiwan
| | - Chun-Fu Fan
- Department of Safety, Health and Environmental Engineering, Ming Chi University of Technology, Taishan, New Taipei 243089, Taiwan
| | - Yu-Hsiang Cheng
- Center for Environmental Sustainability and Human Health, Ming Chi University of Technology, Taishan, New Taipei 243089, Taiwan; Department of Safety, Health and Environmental Engineering, Ming Chi University of Technology, Taishan, New Taipei 243089, Taiwan; Chronic Diseases and Health Promotion Research Center, Chang Gung University of Science and Technology, Puzi, Chiayi 613016, Taiwan.
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5
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Mitroo D, Das DN, Hamilton PD, Kumfer BM, Ravi N. Combustion conditions influence toxicity of flame-generated soot to ocular (ARPE-19) cells. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 344:123307. [PMID: 38190877 DOI: 10.1016/j.envpol.2024.123307] [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: 04/09/2023] [Revised: 12/18/2023] [Accepted: 01/04/2024] [Indexed: 01/10/2024]
Abstract
Soot is a prevalent aerosol found both indoors and outdoors that has several sources, such as natural (e.g., wildfires), civilian (e.g., cooking), or military (e.g., burn pit operation). Additionally, within the sources, factors that influence the physicochemical properties of the soot include combustion temperature, oxygen availability, and fuel type. Being able to reproduce soot in the laboratory and systematically assess its toxicity is important in the pursuit of elucidating pathologies associated with its exposure. Of the organs of interest, we targeted the eye given the scant attention received. Yet, air pollution constituents such as soot have been linked to diseases such as age-related macular degeneration and proliferative vitreoretinopathy. We developed a bench-scale system to synthesize different types of soot, that is, soot with a systematically varied physical attributes or chemical composition. We used common analytical techniques to probe such properties, and used statistical analyses to correlate them with toxicity in vitro using ARPE-19 cells. Within the range of flame conditions studied, we find that soot toxicity increases with increasing oxygen concentration in fuel-rich premixed flames, and weakly increases with decreasing flame temperature. Additionally, soot particles produced in premixed flames are generally smaller in size, exhibit a lesser fractal structure, and are considerably more toxic to ARPE-19 cells than soot particles produced in non-premixed flames.
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Affiliation(s)
- Dhruv Mitroo
- Veterans Research and Education Foundation, St. Louis, MO, 63103, USA; Veterans Affairs Medical Center, St. Louis, MO, 63103, USA
| | - Durgesh N Das
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis MO 63110, USA
| | - Paul D Hamilton
- Veterans Research and Education Foundation, St. Louis, MO, 63103, USA; Veterans Affairs Medical Center, St. Louis, MO, 63103, USA
| | - Benjamin M Kumfer
- Center for Aerosol Science and Engineering, Department of Energy, Environmental, and Chemical Engineering, Washington University, St. Louis, MO 63130, USA
| | - Nathan Ravi
- Veterans Research and Education Foundation, St. Louis, MO, 63103, USA; Veterans Affairs Medical Center, St. Louis, MO, 63103, USA; Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis MO 63110, USA; Center for Aerosol Science and Engineering, Department of Energy, Environmental, and Chemical Engineering, Washington University, St. Louis, MO 63130, USA.
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6
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Chen LWA, Wang X, Lopez B, Wu G, Ho SSH, Chow JC, Watson JG, Yao Q, Yoon S, Jung H. Contributions of non-tailpipe emissions to near-road PM 2.5 and PM 10: A chemical mass balance study. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 335:122283. [PMID: 37517639 DOI: 10.1016/j.envpol.2023.122283] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 07/03/2023] [Accepted: 07/27/2023] [Indexed: 08/01/2023]
Abstract
As the importance of non-tailpipe particles (NTP) over tailpipe emissions from urban traffic has been increasing, there is a need to evaluate NTP contributions to ambient particulate matter (PM) using representative source profiles. The Brake and Tire Wear Study conducted in Los Angeles, California in the winter of 2020 collected 64 PM2.5 and 64 PM10 samples from 32 pairs of downwind-upwind measurements at two near-road locations (I-5 in Anaheim and I-710 in Long Beach). These samples were characterized for inorganic and organic markers and, along with locally-developed brake wear, tire wear, and road dust source profiles, subject to source apportionment using the effective-variance chemical mass balance (EV-CMB) model. Model results highlighted the dominance of resuspended dust in both PM2.5 (23-33%) and PM10 (32-53%). Brake and tire wear contributed more to PM2.5 than tailpipe exhausts (diesel + gasoline) for I-5 (29-30% vs. 19-21%) while they were comparable for I-710 (15-17% vs. 15-19%). For PM10, the brake and tire wear contributions were 2-3 times the exhaust contributions. Different fleet compositions on and near I-5 and I-710 appeared to influence the relative importance of NTP and exhaust sources. The downwind-upwind differences in source contributions were often insignificant, consistent with small and/or nearly equal impacts of adjacent highway traffic emissions on the downwind and upwind sites. The utility of sole markers, such as barium and zinc, to predict brake and tire wear abundances in ambient PM is evaluated.
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Affiliation(s)
- L-W Antony Chen
- Department of Environmental and Occupational Health, School of Public Health, University of Nevada, Las Vegas, 4505 S. Maryland Pkwy, Las Vegas, NV, 89154, USA; Division of Atmospheric Sciences, Desert Research Institute, 2215 Raggio Pkwy, Reno, NV, 89512, USA.
| | - Xiaoliang Wang
- Division of Atmospheric Sciences, Desert Research Institute, 2215 Raggio Pkwy, Reno, NV, 89512, USA
| | - Brenda Lopez
- Department of Mechanical Engineering and Center for Environmental Research and Technology (CE-CERT), University of California-Riverside, 1084 Columbia Ave, Riverside, CA, 92507, USA
| | - Guoyuan Wu
- Department of Mechanical Engineering and Center for Environmental Research and Technology (CE-CERT), University of California-Riverside, 1084 Columbia Ave, Riverside, CA, 92507, USA
| | - Steven Sai Hang Ho
- Division of Atmospheric Sciences, Desert Research Institute, 2215 Raggio Pkwy, Reno, NV, 89512, USA
| | - Judith C Chow
- Division of Atmospheric Sciences, Desert Research Institute, 2215 Raggio Pkwy, Reno, NV, 89512, USA
| | - John G Watson
- Division of Atmospheric Sciences, Desert Research Institute, 2215 Raggio Pkwy, Reno, NV, 89512, USA
| | - Qi Yao
- Research Division, California Air Resources Board, 1001 I St, Sacramento, CA, 95814, USA
| | - Seungju Yoon
- Research Division, California Air Resources Board, 1001 I St, Sacramento, CA, 95814, USA
| | - Heejung Jung
- Department of Mechanical Engineering and Center for Environmental Research and Technology (CE-CERT), University of California-Riverside, 1084 Columbia Ave, Riverside, CA, 92507, USA
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7
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Bhardwaj A, Haswani D, Yadav K, Sunder Raman R. PM 2.5 carbonaceous components and mineral dust at a COALESCE network site - Bhopal, India: Estimating site-specific optical characteristics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 880:163277. [PMID: 37028678 DOI: 10.1016/j.scitotenv.2023.163277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/14/2023] [Accepted: 03/31/2023] [Indexed: 05/27/2023]
Abstract
Atmospheric PM2.5 thermal elemental carbon (EC), optical black carbon (BC), brown carbon (BrC), and mineral dust (MD) were characterized during a field campaign at a regionally representative site (Bhopal, central India) all year-long during 2019. In this study, the optical characteristics of PM2.5 during 'EC-rich', 'OC-rich', and 'MD-rich' days were used in a three-component model to estimate site-specific Absorption Ångström exponent (AAE) and absorption coefficient (babs) of light-absorbing PM2.5 constituents. The AAE for 'EC-rich', 'OC-rich', and 'MD-rich' days were 1.1 ± 0.2, 2.7 ± 0.3, and 3.0 ± 0.9, respectively. The percentage contribution of calculated babs of EC, BrC, and MD to the total babs at 405 nm was dominated by EC during the entire study period (EC; 64 % ± 36 %, BrC: 30 % ± 5 %, MD: 10 % ± 1 %). Further, site-specific mass absorption cross-section (MAC) values were calculated to assess the impact of their use over the use of manufacturer-specified MAC values in estimating BC concentrations. The r2 between thermal EC and optical BC was higher (r2 = 0.67, slope = 1.1) when daily site-specific MAC values were used rather than using the default MAC value (16.6 m2 g-1; r2 = 0.54 and slope = 0.6). Overall, had the default MAC880 been used instead of the site-specific values, we would have underestimated the BC concentration by 39 % ± 18 % during the study period.
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Affiliation(s)
- Ankur Bhardwaj
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal by-pass road, Bhauri, Bhopal 462066, Madhya Pradesh, India
| | - Diksha Haswani
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal by-pass road, Bhauri, Bhopal 462066, Madhya Pradesh, India
| | - Kajal Yadav
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal by-pass road, Bhauri, Bhopal 462066, Madhya Pradesh, India
| | - Ramya Sunder Raman
- Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal by-pass road, Bhauri, Bhopal 462066, Madhya Pradesh, India.
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8
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Feng W, Shao Z, Wang Q, Xie M. Size-resolved light-absorbing organic carbon and organic molecular markers in Nanjing, east China: Seasonal variations and sources. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023:122006. [PMID: 37302787 DOI: 10.1016/j.envpol.2023.122006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 06/07/2023] [Accepted: 06/08/2023] [Indexed: 06/13/2023]
Abstract
Owing to the potential influence of light-absorbing organic carbon (OC), also termed "brown carbon" (BrC), on the planetary radiation budget, many studies have focused on its absorption in single-sized ranges of particulate matter (PM). However, the size distribution and organic tracer-based source apportionment of BrC absorption have not been extensively investigated. In this study, size-resolved PM samples were collected using multi-stage impactors from eastern Nanjing during each season in 2017. The light absorption of methanol-extractable OC at 365 nm (Abs365, Mm-1) was determined using spectrophotometry, and a series of organic molecular markers (OMMs) was measured using a gas chromatography-mass spectrometer. Fine PM with an aerodynamic diameter <2.1 μm (PM2.1) dominated Abs365 (79.8 ± 10.4%) of the total size ranges with maxima and minima in winter and summer, respectively. The distributions of Abs365 shifted to larger PM sizes from winter to spring and summer due to lower primary emissions and increased BrC chromophores in dust. Except for low-volatility (po,*L < 10-10 atm) polycyclic aromatic hydrocarbons (PAHs), the non-polar OMMs, including n-alkanes, PAHs, oxygenated PAHs, and steranes, showed a bimodal distribution pattern. Secondary products of biogenic precursors and biomass burning tracers presented a unimodal distribution peaking at 0.4-0.7 μm, while sugar alcohols and saccharides were enriched in coarse PM. Their seasonal variations in average concentrations reflected intense photochemical reactions in summer, more biomass burning emissions in winter, and stronger microbial activity in spring and summer. Positive matrix factorization was used for the source apportionment of Abs365 in fine and coarse PM samples. Biomass burning contributed an average of 53.9% to the Abs365 of PM2.1 extracts. The Abs365 of coarse PM extracts was associated with various dust-related sources where the aging processes of aerosol organics could occur.
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Affiliation(s)
- Wei Feng
- Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, 219 Ningliu Road, Nanjing, 210044, China
| | - Zhijuan Shao
- School of Environment Science and Engineering, Suzhou University of Science and Technology ShiHu Campus, 99 Xuefu Road, Suzhou, 215009, China
| | - Qin'geng Wang
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Mingjie Xie
- Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, 219 Ningliu Road, Nanjing, 210044, China.
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9
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Ivančič M, Gregorič A, Lavrič G, Alföldy B, Ježek I, Hasheminassab S, Pakbin P, Ahangar F, Sowlat M, Boddeker S, Rigler M. Two-year-long high-time-resolution apportionment of primary and secondary carbonaceous aerosols in the Los Angeles Basin using an advanced total carbon-black carbon (TC-BC(λ)) method. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 848:157606. [PMID: 35896132 DOI: 10.1016/j.scitotenv.2022.157606] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 06/17/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
In recent years, carbonaceous aerosols (CA) have been recognized as a significant contributor to the concentration of particles smaller than 2.5 μm (i.e., PM2.5), with a negative impact on public health and Earth's radiative balance. In this study, we present a method for CA apportionment based on high-time-resolution measurements of total carbon (TC), black carbon (BC), and spectral dependence of absorption coefficient using a recently developed Carbonaceous Aerosol Speciation System (CASS). Two-year-long CA measurements at two different locations within California's Los Angeles Basin are presented. CA was apportioned based on its optical absorption properties, organic or elemental carbon composition, and primary or secondary origin. We found that the secondary organic aerosols (SOA), on average, represent >50 % of CA in the study area, presumably resulting from the oxidation of anthropogenic and biogenic volatile organic components. Remarkable peaks of SOA in summer afternoons were observed, with a fractional contribution of up to 90 %. On the other hand, the peak of primary emitted CA, consisting of BC and primary organic aerosol (POA), contributed >80 % to the CA during morning rush hours on winter working days. The light absorption of BC dominated over the brown carbon (BrC), which contributed to 20 % and 10 % of optical absorption at the lower wavelength of 370 nm during winter nights and summer afternoons, respectively. The highest contribution of BrC, up to 50 %, was observed during the wildfire periods. Although the uncertainty levels can be high for some CA components (such as split between primary emitted and secondary formed BrC during winter nights), further research focused on the optical properties of CA at different locations may help to better constrain the parameters used in CA apportionment studies. We believe that the CASS system combined with the apportionment method presented in this study can offer simplified and cost-effective insights into the composition of carbonaceous aerosols.
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Affiliation(s)
- Matic Ivančič
- Aerosol d.o.o., Research & Development Department, Kamniška 39a, SI-1000 Ljubljana, Slovenia.
| | - Asta Gregorič
- Aerosol d.o.o., Research & Development Department, Kamniška 39a, SI-1000 Ljubljana, Slovenia; Centre for Atmospheric Research, University of Nova Gorica, Vipavska 13, SI-5000 Nova Gorica, Slovenia
| | - Gašper Lavrič
- Aerosol d.o.o., Research & Development Department, Kamniška 39a, SI-1000 Ljubljana, Slovenia
| | - Bálint Alföldy
- Aerosol d.o.o., Research & Development Department, Kamniška 39a, SI-1000 Ljubljana, Slovenia
| | - Irena Ježek
- Aerosol d.o.o., Research & Development Department, Kamniška 39a, SI-1000 Ljubljana, Slovenia
| | - Sina Hasheminassab
- South Coast Air Quality Management District, 21865 Copley Dr, Diamond Bar, CA 91765, USA
| | - Payam Pakbin
- South Coast Air Quality Management District, 21865 Copley Dr, Diamond Bar, CA 91765, USA
| | - Faraz Ahangar
- South Coast Air Quality Management District, 21865 Copley Dr, Diamond Bar, CA 91765, USA
| | - Mohammad Sowlat
- South Coast Air Quality Management District, 21865 Copley Dr, Diamond Bar, CA 91765, USA
| | - Steven Boddeker
- South Coast Air Quality Management District, 21865 Copley Dr, Diamond Bar, CA 91765, USA
| | - Martin Rigler
- Aerosol d.o.o., Research & Development Department, Kamniška 39a, SI-1000 Ljubljana, Slovenia
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Liu S, Luo T, Zhou L, Song T, Wang N, Luo Q, Huang G, Jiang X, Zhou S, Qiu Y, Yang F. Vehicle exhausts contribute high near-UV absorption through carbonaceous aerosol during winter in a fast-growing city of Sichuan Basin, China. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 312:119966. [PMID: 35985435 DOI: 10.1016/j.envpol.2022.119966] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/27/2022] [Accepted: 08/10/2022] [Indexed: 06/15/2023]
Abstract
Carbonaceous aerosols pose significant climatic impact, however, their sources and respective contribution to light absorption vary and remain poorly understood. In this work, filter-based PM2.5 samples were collected in winter of 2021 at three urban sites in Yibin, a fast-growing city in the south of Sichuan Basin, China. The composition characteristics of PM2.5, light absorption and source of carbonaceous aerosol were analyzed. The city-wide average concentration of PM2.5 was 87.4 ± 31.0 μg/m3 in winter. Carbonaceous aerosol was the most abundant species, accounting for 42.5% of the total PM2.5. Source apportionment results showed that vehicular emission was the main source of PM2.5 during winter, contributing 34.6% to PM2.5. The light absorption of black carbon (BC) and brown carbon (BrC) were derived from a simplified two-component model. We apportioned the light absorption of carbonaceous aerosols to BC and BrC using the Least Squares Linear Regression with optimal angstrom absorption exponent of BC (AAEBC). The average absorption of BC and BrC at 405 nm were 51.6 ± 21.5 Mm-1 and 17.7 ± 8.0 Mm-1, respectively, with mean AAEBC = 0.82 ± 0.02. The contribution of BrC to the absorption of carbonaceous reached 26.1% at 405 nm. Based on the PM2.5 source apportionment and the mass absorption cross-section (MAC) value of BrC at 405 nm, vehicle emission was found to be the dominant source of BrC in winter, contributing up to 56.4%. Therefore, vehicle emissions mitigation should be the primary and an effective way to improve atmospheric visibility in this fast-developing city.
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Affiliation(s)
- Song Liu
- College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
| | - Tianzhi Luo
- Yibin Ecological Environment Monitoring Center Station, Sichuan province, Yibin, 644099, China
| | - Li Zhou
- College of Architecture and Environment, Sichuan University, Chengdu, 610065, China.
| | - Tianli Song
- College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
| | - Ning Wang
- College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
| | - Qiong Luo
- College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
| | - Gang Huang
- Yibin Ecological Environment Monitoring Center Station, Sichuan province, Yibin, 644099, China
| | - Xia Jiang
- Yibin Ecological Environment Monitoring Center Station, Sichuan province, Yibin, 644099, China
| | - Shuhua Zhou
- Yibin Ecological Environment Monitoring Center Station, Sichuan province, Yibin, 644099, China
| | - Yang Qiu
- College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
| | - Fumo Yang
- College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
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Apportionment of Vehicle Fleet Emissions by Linear Regression, Positive Matrix Factorization, and Emission Modeling. ATMOSPHERE 2022. [DOI: 10.3390/atmos13071066] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Real-world emission factors for different vehicle types and their contributions to roadside air pollution are needed for air-quality management. Tunnel measurements have been used to estimate emission factors for several vehicle types using linear regression or receptor-based source apportionment. However, the accuracy and uncertainties of these methods have not been sufficiently discussed. This study applies four methods to derive emission factors for different vehicle types from tunnel measurements in Hong Kong, China: (1) simple linear regressions (SLR); (2) multiple linear regressions (MLR); (3) positive matrix factorization (PMF); and (4) EMission FACtors for Hong Kong (EMFAC-HK). Separable vehicle types include those fueled by liquefied petroleum gas (LPG), gasoline, and diesel. PMF was the most useful, as it simultaneously seeks source profiles and source contributions. Diesel-, gasoline-, and LPG-fueled vehicle emissions accounted for 52%, 10%, and 5% of PM2.5 mass, respectively, while ammonium sulfate (~20%), ammonium nitrate (6%), and road dust (7%) were also large contributors. MLR exhibited the highest relative uncertainties, typically over twice those determined by SLR. EMFAC-HK has the lowest relative uncertainties due to its assumption of a single average emission factor for each pollutant and each vehicle category under specific conditions. The relative uncertainties of SLR and PMF are comparable.
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12
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Optical Characterization of Fresh and Photochemically Aged Aerosols Emitted from Laboratory Siberian Peat Burning. ATMOSPHERE 2022. [DOI: 10.3390/atmos13030386] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Carbonaceous aerosols emitted from biomass burning influence radiative forcing and climate change. Of particular interest are emissions from high-latitude peat burning because amplified climate change makes the large carbon mass stored in these peatlands more susceptible to wildfires and their emission can affect cryosphere albedo and air quality after undergoing transport. We combusted Siberian peat in a laboratory biomass-burning facility and characterized the optical properties of freshly emitted combustion aerosols and those photochemically aged in an oxidation flow reactor (OFR) with a three-wavelength photoacoustic instrument. Total particle count increased with aging by a factor of 6 to 11 while the total particle volume either changed little (<8%) for 19 and 44 days of equivalent aging and increased by 88% for 61 days of equivalent aging. The aerosol single-scattering albedo (SSA) of both fresh and aged aerosol increased with the increasing wavelength. The largest changes in SSA due to OFR aging were observed at the shortest of the three wavelengths (i.e., at 405 nm) where SSA increased by less than ~2.4% for 19 and 44 days of aging. These changes were due to a decrease in the absorption coefficients by ~45%, with the effect on SSA somewhat reduced by a concurrent decrease in the scattering coefficients by 20 to 25%. For 61 days of aging, we observed very little change in SSA, namely an increase of 0.31% that was caused a ~56% increase in the absorption coefficients that was more than balanced by a somewhat larger (~71%) increase in the scattering coefficients. These large increases in the absorption and scattering coefficients for aging at 7 V are at least qualitatively consistent with the large increase in the particle volume (~88%). Overall, aging shifted the absorption toward longer wavelengths and decreased the absorption Ångström exponents, which ranged from ~5 to 9. Complex refractive index retrieval yielded real and imaginary parts that increased and decreased, respectively, with the increasing wavelength. The 405 nm real parts first increased and then decreased and imaginary parts decreased during aging, with little change at other wavelengths.
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