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Liu X, Wu C, Li Z, Li R, Wang F, Lv S, Li R, Zhang F, Wang H, Liang C, Zhang L, Wang G. Atmospheric brown carbon in China haze is dominated by secondary formation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 945:173901. [PMID: 38880143 DOI: 10.1016/j.scitotenv.2024.173901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 06/02/2024] [Accepted: 06/08/2024] [Indexed: 06/18/2024]
Abstract
Brown carbon (BrC) is a class of light-absorbing organic aerosols (OA) and has significant influence on atmospheric radiative forcing. However, the current limited understanding of the physicochemical properties of BrC restricts the accurate evaluation of its environmental effects. Here the optical characteristics and chemical composition of BrC during wintertime in the Yangtze River Delta (YRD) region, China were measured by using high-resolution aerosol mass spectrometry (HR-AMS) and UV-vis spectrometry. Our results showed that BrC in PM2.5 during the campaign was dominated by water-soluble organics, which consist of less oxidized oxygenated OA (LO-OOA), more oxidized oxygenated OA (MO-OOA), fossil fuel OA (FFOA) and biomass burning OA (BBOA). MO-OOA and BBOA were the strongest light absorbing BrC at 365 nm (Abs365), followed by LO-OOA and FFOA with a mass absorption coefficient (MAC) being 0.74 ± 0.04, 0.73 ± 0.03, 0.48 ± 0.04 and 0.39 ± 0.06 m2 g-1 during the campaign, respectively. In the low relative humidity (RH < 80 %) haze periods Abs365 of LO-OOA contributed to 44 % of the total light absorption at 365 nm, followed by MO-OOA (31 %), FFOA (21 %) and BBOA (4 %). In contrast, in the high-RH (RH > 80 %) haze periods Abs365 was dominated by MO-OOA, which accounted for 62 % of the total Abs365, followed by LO-OOA (17 %), BBOA (13 %) and FFOA (8 %). Chemical composition analysis further showed that LO-OOA and MO-OOA are produced from gas-phase photooxidation of VOCs and aerosol aqueous reactions, respectively, in which ammonia significantly enhanced the formation and light absorption of BrC in the high RH haze period. On average, >75 % of the total Abs365nm in the YRD region during the haze events was contributed by LO-OOA and MO-OOA, suggesting that atmospheric BrC in China haze periods is predominantly formed by secondary reactions.
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Affiliation(s)
- Xiaodi Liu
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Can Wu
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Zheng Li
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Rongjie Li
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Fanglin Wang
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Shaojun Lv
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Rui Li
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Fan Zhang
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Haoyang Wang
- Laboratory of Mass Spectrometry Analysis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Chenlong Liang
- Laboratory of Mass Spectrometry Analysis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
| | - Lei Zhang
- China Academy of Meteorological Sciences, Beijing, China
| | - Gehui Wang
- Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China.
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Bao Z, Zeng X, Zhou J, Yang F, Lu K, Zhai C, Li X, Feng M, Tan Q, Chen Y. Evolution of black carbon and brown carbon during summertime in Southwestern China: An assessment of control measures during the 2023 Chengdu Summer World University Games. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 357:124467. [PMID: 38950850 DOI: 10.1016/j.envpol.2024.124467] [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: 04/03/2024] [Revised: 06/24/2024] [Accepted: 06/26/2024] [Indexed: 07/03/2024]
Abstract
The 31st FISU Summer World University Games (SWUG) was held in Chengdu, southwestern China, from July 22 to August 8, 2023. A series of control measures were carried out to ensure good air quality during the SWUG, providing an opportunity to investigate the atmospheric behaviors of light-absorbing aerosols under such a substantial disturbance caused by the control measures. To assess the impacts of emission controls on primary pollutants, a field campaign was conducted at a rural site in Chengdu to investigate the characterization of equivalent black carbon (eBC). The changes of eBC concentrations before, during, and after the SWUG were characterized. The sources of eBC were resolved, and the impacts of atmospheric processes on the absorption capacity were also investigated. During the SWUG, the eBC concentration decreased by 12.1 % and 25.3 % compared with those before and after the SWUG. A fossil fuel combustion (eBCff) and a biomass burning (eBCbb) originated eBC were resolved using the aethalometer model. Both eBCff and eBCbb decreased during the SWUG, indicating the effectiveness of control measures. After the SWUG, the influence of biomass burning emissions became more and more significant, and the contribution of brown carbon (BrC) to light absorption at 370-660 nm increased by 52, 19, 7, 6, and 17 % compared to those during the SWUG. As the biomass burning emitted aerosols aged, the absorption Ångström exponent and babs(BrC370nm) decreased gradually, which was mainly due to the photobleaching of the chromophores during the daytime. eBCff was mainly affected by strong wind, while high eBCbb concentration was mainly attributed to the gradual accumulation of biomass-burning emissions near the observation site. The results show the significant reduction of eBC with the implementation of the air pollution mitigation campaign, and provide insights on the impacts of atmospheric processes on BC optical properties during summertime.
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Affiliation(s)
- Zhier Bao
- Research Center for Atmospheric Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China
| | - Xiaoling Zeng
- Research Center for Atmospheric Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China
| | - Jiawei Zhou
- Research Center for Atmospheric Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China
| | - Fumo Yang
- College of Carbon Neutrality Future Technology, Sichuan University, Chengdu, 610065, China
| | - Keding Lu
- SKL-ESPC and BIC-ESAT, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Chongzhi Zhai
- Chongqing Key Laboratory of Urban Atmospheric Environment Observation and Pollution Prevention, Chongqing, 401147, China
| | - Xin Li
- SKL-ESPC and BIC-ESAT, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China
| | - Miao Feng
- Chengdu Academy of Environmental Sciences, Chengdu, 610072, China
| | - Qinwen Tan
- Chengdu Academy of Environmental Sciences, Chengdu, 610072, China
| | - Yang Chen
- Research Center for Atmospheric Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China.
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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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Cao N, Chen L, Liu Y, Wang J, Yang S, Su D, Mi K, Gao S, Zhang H. Spatiotemporal distribution, light absorption characteristics, and source apportionments of black and brown carbon in China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 919:170796. [PMID: 38336053 DOI: 10.1016/j.scitotenv.2024.170796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/30/2024] [Accepted: 02/06/2024] [Indexed: 02/12/2024]
Abstract
Black carbon (BC) and brown carbon (BrC) are aerosols that absorb light and thereby contribute to climate change. In this study, the light absorption properties and spatiotemporal distributions of equivalent BC (eBC) and BrC aerosols were determined based on continuous measurements of aerosol light absorption from January to August 2017, using a seven-channel aethalometer at 49 sampling sites in China. The source apportionments of BC and BrC were identified using the BC/PM2.5, absorption Ångström exponent, the concentration-weighted trajectory method, and the random forest model. Based on the results, BC was the dominant light absorber, whereas BrC was responsible for a higher proportion of the light absorption in northern compared to southern China. The light absorption of BrC was highest in winter (34.3 Mm-1), followed by spring (19.0 Mm-1) and summer (3.6 Mm-1). The combustion of liquid fuels accounted for over 50 % of the light absorption coefficient of BC in most cities and the importance of carbon monoxide (CO) and nitrogen dioxide (NO2) was over 10 % for BC emitted by liquid fuel combustion, based on the random forest model. The contribution of solid fuel combustion to BC in the north was larger than that in the southern regions as coal combustion and crop residue burning are important emission sources of BC in most northern cities. The contribution of primary BrC to light absorption was high in some northern cities, whereas that of secondary BrC was prevalent in some southern cities. The diurnal variations in secondary BrC were affected by changes in odd oxygen and relative humidity, which promoted the photobleaching of the chromophores and aqueous-phase reactions of secondary BrC.
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Affiliation(s)
- Nan Cao
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Li Chen
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China.
| | - Yusi Liu
- State Key Laboratory of Severe Weather, Key Laboratory for Atmospheric Chemistry of China Meteorology Administration, Chinese Academy of Meteorological Sciences, Beijing 100081, China.
| | - Jing Wang
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Shuangqin Yang
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Die Su
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Ke Mi
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Shuang Gao
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
| | - Hu Zhang
- School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
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5
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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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Characterization of Imidazole Compounds in Aqueous Secondary Organic Aerosol Generated from Evaporation of Droplets Containing Pyruvaldehyde and Inorganic Ammonium. ATMOSPHERE 2022. [DOI: 10.3390/atmos13060970] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Imidazole compounds are important constituents of atmospheric brown carbon. The imidazole components of aqueous secondary organic aerosol (aqSOA) that are generated from the evaporation of droplets containing pyruvaldehyde and inorganic ammonium are on-line characterized by an aerosol laser time-of-flight mass spectrometer (ALTOFMS) and off-line detected by optical spectrometry in this study. The results demonstrated that the laser desorption/ionization mass spectra of aqSOA particles that were detected by ALTOFMS contained the characteristic mass peaks of imidazoles at m/z = 28 (CH2N+), m/z = 41 (C2H3N+) and m/z = 67 (C3H4N2+). Meanwhile, the extraction solution of the aqSOA particles that were measured by off-line techniques showed that the characteristic absorption peaks at 217 nm and 282 nm appeared in the UV-Vis spectrum, and the stretching vibration peaks of C-N bond and C=N bond emerged in the infrared spectrum. Based on these spectral information, 4-methyl-imidazole and 4-methyl-imidazole-2-carboxaldehyde are identified as the main products of the reaction between pyruvaldehyde and ammonium ions. The water evaporation accelerates the formation of imidazoles inside the droplets, possibly owing to the highly concentrated environment. Anions, such as F−, CO32−, NO3−, SO42− and Cl− in the aqueous phase promote the reaction of pyruvaldehyde and ammonium ions to produce imidazole products, resulting in the averaged mass absorption coefficient (<MAC>) in the range of 200–600 nm of aqSOA increases, and the order of promotion is: F− > CO32− > SO42− ≈ NO3− ≈ Cl−. These results will help to analyze the constituents and optics of imidazoles and provide a useful basis for evaluating the formation process and radiative forcing of aqSOA particles.
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He Q, Li C, Siemens K, Morales AC, Hettiyadura AP, Laskin A, Rudich Y. Optical Properties of Secondary Organic Aerosol Produced by Photooxidation of Naphthalene under NOx Condition. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:4816-4827. [PMID: 35384654 PMCID: PMC9022426 DOI: 10.1021/acs.est.1c07328] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/26/2022] [Accepted: 03/23/2022] [Indexed: 05/21/2023]
Abstract
Secondary organic aerosols (SOAs) affect incoming solar radiation by interacting with light at ultraviolet and visible wavelength ranges. However, the relationship between the chemical composition and optical properties of SOA is still not well understood. In this study, the complex refractive index (RI) of SOA produced from OH oxidation of naphthalene in the presence of nitrogen oxides (NOx) was retrieved online in the wavelength range of 315-650 nm and the bulk chemical composition of the SOA was characterized by an online high-resolution time-of-flight mass spectrometer. In addition, the molecular-level composition of brown carbon chromophores was determined using high-performance liquid chromatography coupled to a photodiode array detector and a high-resolution mass spectrometer. The real part of the RI of the SOA increases with both the NOx/naphthalene ratio and aging time, likely due to the increased mean polarizability and decreased molecular weight due to fragmentation. Highly absorbing nitroaromatics (e.g., C6H5NO4, C7H7NO4, C7H5NO5, C8H5NO5) produced under higher NOx conditions contribute significantly to the light absorption of the SOA. The imaginary part of the RI linearly increases with the NOx/VOCs ratio due to the formation of nitroaromatic compounds. As a function of aging, the imaginary RI increases with the O/C ratio (slope = 0.024), mainly attributed to the achieved higher NOx/VOCs ratio, which favors the formation of light-absorbing nitroaromatics. The light-absorbing enhancement is not as significant with extensive aging as it is under a lower aging time due to the opening of aromatic rings by reactions.
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Affiliation(s)
- Quanfu He
- Department
of Earth and Planetary Sciences, Weizmann
Institute of Science, Rehovot 76100, Israel
| | - Chunlin Li
- Department
of Earth and Planetary Sciences, Weizmann
Institute of Science, Rehovot 76100, Israel
| | - Kyla Siemens
- Department of Chemistry, Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana 47907, United States
| | - Ana C. Morales
- Department of Chemistry, Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana 47907, United States
| | | | - Alexander Laskin
- Department of Chemistry, Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, Indiana 47907, United States
| | - Yinon Rudich
- Department
of Earth and Planetary Sciences, Weizmann
Institute of Science, Rehovot 76100, Israel
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8
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Cheng Y, Cao XB, Liu JM, Yu QQ, Wang P, Yan CQ, Du ZY, Liang LL, Zhang Q, He KB. Primary nature of brown carbon absorption in a frigid atmosphere with strong haze chemistry. ENVIRONMENTAL RESEARCH 2022; 204:112324. [PMID: 34742712 DOI: 10.1016/j.envres.2021.112324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/29/2021] [Accepted: 10/29/2021] [Indexed: 06/13/2023]
Abstract
Severe haze hovered over Harbin during the heating season of 2019-2020, making it one of the ten most polluted Chinese cities in January of 2020. Here we focused on the optical properties and sources of brown carbon (BrC) during the extreme atmospheric pollution periods. Enhanced formation of secondary BrC (BrCsec) was evident as relative humidity (RH) became higher, accompanied with a decrease of ozone but concurrent increases of aerosol water content and secondary inorganic aerosols. These features were generally similar to the characteristics of haze chemistry observed during winter haze events in the North China Plain, and indicated that heterogeneous reactions involving aerosol water might be at play in the formation of BrCsec, despite the low temperatures in Harbin. Although BrCsec accounted for a substantial fraction of brown carbon mass, its contribution to BrC absorption was much smaller (6 vs. 28%), pointing to a lower mass absorption efficiency (MAE) of BrCsec compared to primary BrC. In addition, emissions of biomass burning BrC (BrCBB) were inferred to increase with increasing RH, coinciding with a large drop of temperature. Since both the less absorbing BrCsec and the more absorbing BrCBB increased as RH became higher, the MAE of total BrC were largely unchanged throughout the measurement period. This study unfolded the contrast in the source apportionment results of BrC mass and absorption, and could have implications for the simulation of radiative forcing by brown carbon.
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Affiliation(s)
- Yuan Cheng
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Xu-Bing Cao
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Jiu-Meng Liu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
| | - Qin-Qin Yu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Peng Wang
- Longfengshan Regional Atmospheric Background Station, Heilongjiang Meteorological Bureau, Harbin, 150200, China
| | - Cai-Qing Yan
- Environment Research Institute, Shandong University, Qingdao, 266237, China
| | - Zhen-Yu Du
- National Research Center for Environmental Analysis and Measurement, Environmental Development Center of the Ministry of Ecology and Environment, Beijing, 100029, China.
| | - Lin-Lin Liang
- State Key Laboratory of Severe Weather & CMA Key Laboratory for Atmospheric Chemistry, Chinese Academy of Meteorological Sciences, Beijing, 100081, China
| | - Qiang Zhang
- Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, 100084, China
| | - Ke-Bin He
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China
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Olson MR, Yuqin W, de Foy B, Li Z, Bergin MH, Zhang Y, Schauer JJ. Source attribution of black and Brown carbon near-UV light absorption in Beijing, China and the impact of regional air-mass transport. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 807:150871. [PMID: 34634351 DOI: 10.1016/j.scitotenv.2021.150871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 10/03/2021] [Accepted: 10/04/2021] [Indexed: 06/13/2023]
Abstract
Black and Brown Carbon (BC, BrC) are key parameters of climate forcing, yet significant challenges exist assigning emission source contributions to light-absorption by carbonaceous aerosols. Additionally, BC and BrC emissions add to extreme air pollution events in Chinese mega-cities, which harm human health and detract from the natural and built environment. To address these concerns, the ability to estimate atmospheric light absorption related to emission sources and global inventories is a highly valuable tool for climate modelers and policy makers. Three months of BC and BrC data was collected using an Aethalometer in parallel to PM2.5 filter sampling during a stringent emission controls period and post controls period, including during the regional heating season. In this study reconstructed 370 nm wavelength absorption was calculated by applying source specific Mass Absorption Cross-Sections to PMF apportioned EC and OC results. Reconstructed absorption showed good agreement with the ambient measured absorption for both BC and BrC. In Beijing, the major contributor to near-UV absorption was mobile sources, which accounted for 45-54% of absorption by BC and 14-18% by BrC. BrC absorption from secondary aerosols, biomass burning, and soil dust was also estimated, with these sources contributing from 1 to 9% individually. Meteorological cluster analysis showed that air mass origin did not impact the absorption reconstruction and that the highest regional contribution to near-UV light absorption originated primarily in areas south and east of Beijing. The study shows ambient near-UV light absorption can be predicted using BC and BrC MAC values from sources. However, the current number of multi-wavelength and source specific BrC MAC values reported in the literature is limited. The reconstruction approach allows for a more robust method of assigning light absorption to source categories, allowing the expansion of aethalometer derived BrC apportionment to multiple sources, including biomass burning.
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Affiliation(s)
- Michael R Olson
- Water Science and Engineering Laboratory, 660 North Park Street, Madison, WI 53706, United States of America; California Air Resources Board, 8340 Ferguson Ave, Sacramento, CA 95828, United States of America.
| | - Wang Yuqin
- Shaanxi University of Science and Technology, College of Environmental Science and Engineering, Weiyang Universities Zone, Weiyang District, Xi'an, Shaanxi 710021, China.
| | - Benjamin de Foy
- Saint Louis University, Department of Earth and Atmospheric Sciences, 3642 Lindell Blvd., Room 300E, St. Louis, MO 63108, United States of America.
| | - Zhengqiang Li
- State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing Applications, Chinese Academy of Sciences, Beijing 100094, China.
| | - Michael H Bergin
- Duke University, Department of Civil and Environmental Engineering, 127B Hudson Hall, Box 90287, Durham, NC 27708, United States of America.
| | - Yuanxun Zhang
- College of Resources and Environment, University of Chinese Academy of Sciences, 380 Huaibei Town, Huairou District, Beijing 101408, China.
| | - James Jay Schauer
- University of Wisconsin Madison, Water Science and Engineering Laboratory, 660 North Park Street, Madison, WI 53706, United States of America.
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10
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Gao Y, Wang Q, Li L, Dai W, Yu J, Ding L, Li J, Xin B, Ran W, Han Y, Cao J. Optical properties of mountain primary and secondary brown carbon aerosols in summertime. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150570. [PMID: 34582869 DOI: 10.1016/j.scitotenv.2021.150570] [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: 07/24/2021] [Revised: 09/18/2021] [Accepted: 09/20/2021] [Indexed: 06/13/2023]
Abstract
Brown carbon (BrC) can affect atmospheric radiation due to its strong absorption ability from the near ultraviolet to the visible range, thereby influencing global climate. However, given the complexity of BrC's chemical composition, its optical properties are still poorly understood, especially in mountainous areas. In this study, the black carbon (BC) tracer method is used to explore the light-absorbing properties of primary and secondary BrC at Mount Hua, China during the 2018 summer period. The primary BrC absorption contributes to 10-15% of the total BrC absorption at a wavelength of 370 nm. From the positive matrix factorization analysis, traffic emissions are found to be a major source of primary BrC absorption (44%), followed by industry and biomass-burning emissions (29%). The secondary BrC accounts for 87% of the total BrC absorption at a wavelength of 370 nm, indicating that BrC is dominated by secondary formation. The observation of a higher secondary BrC absorption diurnal pattern at Mount Hua can be affected by secondary BrC in the residual layer after sunrise and the formation of light-absorbing chromophores by photochemical oxidation in the afternoon. The estimated average mass absorption efficiencies of primary and secondary BrC (MAE_pri and MAE_sec, respectively) are 0.4 m2/g and 2.1 m2/g at wavelengths of 370 nm, respectively, indicating a stronger light-absorbing ability for secondary BrC than for primary BrC. There is no significant difference in MAE_pri within a daily variation, but the daytime MAE_sec value is higher than that during the night. Our study shows that secondary BrC is important to light absorption in mountainous areas.
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Affiliation(s)
- Yuan Gao
- Advanced Institute of Natural Sciences, Beijing Normal University at Zhuhai, 519087, China
| | - Qiyuan Wang
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; CAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, China; Guanzhong Plain Ecological Environment Change and Comprehensive Treatment National Observation and Research Station, China.
| | - Li Li
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Wenting Dai
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Jinjiang Yu
- Huashan Meteorological Station, Weinan 714000, China
| | - Limin Ding
- Huashan Meteorological Station, Weinan 714000, China
| | - Jianjun Li
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Bo Xin
- Weinan Meteorological Administration, Weinan 714000, China
| | - Weikang Ran
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Yongming Han
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China; CAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, China; Guanzhong Plain Ecological Environment Change and Comprehensive Treatment National Observation and Research Station, China
| | - Junji Cao
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.
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11
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Rastogi N, Satish R, Singh A, Kumar V, Thamban N, Lalchandani V, Shukla A, Vats P, Tripathi SN, Ganguly D, Slowik J, Prevot ASH. Diurnal variability in the spectral characteristics and sources of water-soluble brown carbon aerosols over Delhi. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 794:148589. [PMID: 34214816 DOI: 10.1016/j.scitotenv.2021.148589] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 06/01/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
It is well established that light-absorbing organic aerosols (commonly known as brown carbon, BrC) impact climate. However, uncertainties remain as their contributions to absorption at different wavelengths are often ignored in climate models. Further, BrC exhibits differences in absorption at different wavelengths due to the variable composition including varying sources and meteorological conditions. However, diurnal variability in the spectral characteristics of water-soluble BrC (hereafter BrC) is not yet reported. This study presents unique measurement hitherto lacking in the literature. Online measurements of BrC were performed using an assembled system including a particle-into-liquid sampler, portable UV-Visible spectrophotometer with liquid waveguid capillary cell, and total carbon analyzer (PILS-LWCC-TOC). This system measured the absorption of ambient aerosol extracts at the wavelengths ranging from 300 to 600 nm with 2 min integration time and water-soluble organic carbon (WSOC) with 4 min integration time over a polluted megacity, New Delhi. Black carbon, carbon monoxide (CO), nitrogen oxides (NOx), and the chemical composition of non-refractory submicron aerosols were also measured in parallel. Diurnal variability in absorption coefficient (0.05 to 65 Mm-1), mass absorption efficiency (0.01 to 3.4 m-2 gC-1) at 365 nm, and absorption angstrom exponent (AAE) of BrC for different wavelength range (AAE300-400: 4.2-5.8; AAE400-600: 5.5-8.0; and AAE300-600: 5.3-7.3) is discussed. BrC chromophores absorbing at any wavelength showed minimum absorption during afternoon hours, suggesting the effects of boundary layer expansion and their photo-sensitive/volatile nature. On certain days, a considerable presence of BrC absorbing at 490 nm was observed during nighttime that disappears during the daytime. It appeared to be associated with secondary BrC. Observations also infer that BrC species emitted from the biomass and coal burning are more absorbing among all sources. A fraction of BrC is likely associated with trash burning, as inferred from the spectral characteristics of Factor-3 from the PMF analysis of BrC spectra. Such studies are essential in understanding the BrC characteristics and their further utilization in climate models.
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Affiliation(s)
- Neeraj Rastogi
- Geosciences Division, Physical Research Laboratory, Ahmedabad 380009, India.
| | - Rangu Satish
- Geosciences Division, Physical Research Laboratory, Ahmedabad 380009, India
| | - Atinderpal Singh
- Geosciences Division, Physical Research Laboratory, Ahmedabad 380009, India
| | - Varun Kumar
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen 5232, Switzerland
| | - Navaneeth Thamban
- Department of Civil Engineering and Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Vipul Lalchandani
- Department of Civil Engineering and Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Ashutosh Shukla
- Department of Civil Engineering and Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Pawan Vats
- Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - S N Tripathi
- Department of Civil Engineering and Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Dilip Ganguly
- Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Jay Slowik
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen 5232, Switzerland
| | - Andre S H Prevot
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen 5232, Switzerland
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12
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Li X, Hu M, Wang Y, Xu N, Fan H, Zong T, Wu Z, Guo S, Zhu W, Chen S, Dong H, Zeng L, Yu X, Tang X. Links between the optical properties and chemical compositions of brown carbon chromophores in different environments: Contributions and formation of functionalized aromatic compounds. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 786:147418. [PMID: 33975110 DOI: 10.1016/j.scitotenv.2021.147418] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/19/2021] [Accepted: 04/24/2021] [Indexed: 06/12/2023]
Abstract
Links between the optical properties and chemical compositions of brown carbon (BrC) are poorly understood because of the complexity of BrC chromophores. We conducted field studies simultaneously at both vehicle-influenced site and biomass burning-affected site in China in polluted winter. The chemical compositions and light absorption values of functionalized aromatic compounds, including phenyl aldehyde, phenyl acid, and nitroaromatic compounds, were measured. P-phthalic acid, nitrophenols and nitrocatechols were dominant BrC species, accounting for over 50% of the concentration of identified chromophores. Nitrophenols and nitrocatechols contributed more than 50% of the identified BrC absorbance between 300 and 400 nm. Oxidation of biomass burning-related products (e.g., pyrocatechol and methylcatechols) and anthropogenic volatile organic compounds (e.g., benzene and toluene) generated similar BrC chromophores, implying that these functionalized aromatic compounds play an important role in both environments. Compared with the biomass burning-affected site (22%), functionalized aromatic compounds at vehicle-influenced site accounted for a higher percentage of BrC absorption (25%). This research improves our understanding of the links between optical properties and composition of BrC, and the difference between BrC chromophores from BB-influenced area and vehicle-affected area under polluted atmospheric conditions.
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Affiliation(s)
- Xiao Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Min Hu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science & Technology, Nanjing, China; Beijing Innovation Center for Engineering Sciences and Advanced Technology, Peking University, Beijing, China.
| | - Yujue Wang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Nan Xu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Hanyun Fan
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Taomou Zong
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Zhijun Wu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science & Technology, Nanjing, China
| | - Song Guo
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science & Technology, Nanjing, China
| | - Wenfei Zhu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Shiyi Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Huabin Dong
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Limin Zeng
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xuena Yu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xiaoyan Tang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
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13
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Zhu M, Huang M, Xue B, Cai S, Hu C, Zhao W, Gu X, Zhang W. Chemical analysis of nitro‐aromatic compounds of secondary organic aerosol formed from photooxidation of p‐xylene with NO
x. J CHIN CHEM SOC-TAIP 2021. [DOI: 10.1002/jccs.202100105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Min‐Cong Zhu
- Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, College of Chemistry and Chemical Engineering and Environment Minnan Normal University Zhangzhou China
| | - Ming‐Qiang Huang
- Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, College of Chemistry and Chemical Engineering and Environment Minnan Normal University Zhangzhou China
| | - Bing‐Bing Xue
- Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, College of Chemistry and Chemical Engineering and Environment Minnan Normal University Zhangzhou China
| | - Shun‐You Cai
- Fujian Provincial Key Laboratory of Modern Analytical Science and Separation Technology, College of Chemistry and Chemical Engineering and Environment Minnan Normal University Zhangzhou China
| | - Chang‐Jin Hu
- Laboratory of Atmospheric Physico‐Chemistry, Anhui Institute of Optics and Fine Mechanics Chinese Academy of Sciences Hefei China
| | - Wei‐Xiong Zhao
- Laboratory of Atmospheric Physico‐Chemistry, Anhui Institute of Optics and Fine Mechanics Chinese Academy of Sciences Hefei China
| | - Xue‐Jun Gu
- Laboratory of Atmospheric Physico‐Chemistry, Anhui Institute of Optics and Fine Mechanics Chinese Academy of Sciences Hefei China
| | - Wei‐Jun Zhang
- Laboratory of Atmospheric Physico‐Chemistry, Anhui Institute of Optics and Fine Mechanics Chinese Academy of Sciences Hefei China
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14
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Tapavicza E, von Rudorff GF, De Haan DO, Contin M, George C, Riva M, von Lilienfeld OA. Elucidating an Atmospheric Brown Carbon Species-Toward Supplanting Chemical Intuition with Exhaustive Enumeration and Machine Learning. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:8447-8457. [PMID: 34080853 DOI: 10.1021/acs.est.1c00885] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Brown carbon (BrC) is involved in atmospheric light absorption and climate forcing and can cause adverse health effects. Understanding the formation mechanisms and molecular structure of BrC is of key importance in developing strategies to control its environment and health impact. Structure determination of BrC is challenging, due to the lack of experiments providing molecular fingerprints and the sheer number of molecular candidates with identical mass. Suggestions based on chemical intuition are prone to errors due to the inherent bias. We present an unbiased algorithm, using graph-based molecule generation and machine learning, which can identify all molecular structures of compounds involved in biomass burning and the composition of BrC. We apply this algorithm to C12H12O7, a light-absorbing "test case" molecule identified in chamber experiments on the aqueous photo-oxidation of syringol, a prevalent marker in wood smoke. Of the 260 million molecular graphs, the algorithm leaves only 36,518 (0.01%) as viable candidates matching the spectrum. Although no unique molecular structure is obtained from only a chemical formula and a UV/vis absorption spectrum, we discuss further reduction strategies and their efficacy. With additional data, the method can potentially more rapidly identify isomers extracted from lab and field aerosol particles without introducing human bias.
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Affiliation(s)
- Enrico Tapavicza
- Department of Chemistry and Biochemistry, California State University, Long Beach, 1250 Bellflower Boulevard, Long Beach, California 90840, United States
| | - Guido Falk von Rudorff
- Faculty of Physics, University of Vienna, Kolingasse 14-16, AT-1090 Wien, Austria
- Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland
| | - David O De Haan
- Department of Chemistry and Biochemistry, University of San Diego, 5998 Alcala Park, San Diego, California 92110, United States
| | - Mario Contin
- Facultad de Farmacia y Bioquímica, Departamento de Química Analitica y Fisicoquímica, Universidad de Buenos Aires, Junín 956, Buenos Aires C1113AAD, Argentina
| | - Christian George
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON, 69626 Villeurbanne, France
| | - Matthieu Riva
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON, 69626 Villeurbanne, France
| | - O Anatole von Lilienfeld
- Faculty of Physics, University of Vienna, Kolingasse 14-16, AT-1090 Wien, Austria
- Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland
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15
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Sun J, Xie C, Xu W, Chen C, Ma N, Xu W, Lei L, Li Z, He Y, Qiu Y, Wang Q, Pan X, Su H, Cheng Y, Wu C, Fu P, Wang Z, Sun Y. Light absorption of black carbon and brown carbon in winter in North China Plain: comparisons between urban and rural sites. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 770:144821. [PMID: 33736402 DOI: 10.1016/j.scitotenv.2020.144821] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/20/2020] [Accepted: 12/23/2020] [Indexed: 05/19/2023]
Abstract
The light absorption black carbon (BC) and brown carbon (BrC) are two important sources of uncertainties in radiative forcing estimate. Here we investigated the light absorption enhancement (Eabs) of BC due to coated materials at an urban (Beijing) and a rural site (Gucheng) in North China Plain (NCP) in winter 2019 by using a photoacoustic extinctiometer coupled with a thermodenuder. Our results showed that the average (±1σ) Eabs was 1.32 (±0.15) at the rural site, which was slightly higher than that at the urban site (1.24 ± 0.15). The dependence of Eabs on coating materials was found to be relatively limited at both sites. However, Eabs presented considerable increases as a function of relative humidity below 70%. Further analysis showed that Eabs during non-heating period in Beijing was mainly caused by secondary components, while it was dominantly contributed by enhanced primary emissions in heating season at both sites. In particular, aerosol particles mixed with coal combustion emissions had a large impact on Eabs (>1.40), while the fresh traffic emissions and freshly oxidized secondary OA (SOA) had limited Eabs (1.00-1.23). Although highly aged or aqueous-phase processed SOA coated on BC showed the largest Eabs, their contributions to the bulk absorption enhancement were generally small. We also quantified the absorption of BrC and source contributions. The results showed the BrC absorption at the rural site was nearly twice that of urban site, yet absorption Ångström exponents were similar. Multiple linear regression analysis highlighted the major sources of BrC being coal combustion emissions and photochemical SOA at both sites with additional biomass burning at the rural site. Overall, our results demonstrated the relatively limited winter light absorption enhancement of BC in different chemical environments in NCP, which needs be considered in regional climate models to improve BC radiative forcing estimates.
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Affiliation(s)
- 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
| | - Conghui Xie
- 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
| | - Weiqi Xu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, 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
| | - Nan Ma
- Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China
| | - Wanyun Xu
- State Key Laboratory of Severe Weather & Key Laboratory for Atmospheric Chemistry, Institute of Atmospheric Composition, Chinese Academy of Meteorological Sciences, Beijing 100081, 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
| | - 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
| | - Yao He
- 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
| | - Yanmei Qiu
- 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
| | - Qingqing Wang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Xiaole Pan
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Hang Su
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz 55128, Germany
| | - Yafang Cheng
- Minerva Research Group, Max Planck Institute for Chemistry, Mainz 55128, Germany
| | - Cheng Wu
- Institute of Mass Spectrometer and Atmospheric Environment, Jinan University, Guangzhou, China
| | - Pingqing Fu
- Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China
| | - Zifa Wang
- 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; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, 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; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
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16
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Pani SK, Lin NH, Griffith SM, Chantara S, Lee CT, Thepnuan D, Tsai YI. Brown carbon light absorption over an urban environment in northern peninsular Southeast Asia. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 276:116735. [PMID: 33611195 DOI: 10.1016/j.envpol.2021.116735] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/17/2021] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
Light-absorbing organic carbon (or brown carbon, BrC) has been recognized as a critical driver in regional-to-global climate change on account of its significant contribution to light absorption. BrC sources vary from primary combustion processes (burning of biomass, biofuel, and fossil fuel) to secondary formation in the atmosphere. This paper investigated the light-absorbing properties of BrC such as site-specific mass absorption cross-section (MACBrC), absorption Ångström exponent (AAEBrC), and the absorbing component of the refractive index (kBrC) by using light absorption measurements from a 7-wavelength aethalometer over an urban environment of Chiang Mai, Thailand in northern peninsular Southeast Asia (PSEA), from March to April 2016. The contribution of BrC to total aerosol absorption (mean ± SD) was 46 ± 9%, 29 ± 7%, 24 ± 6%, 20 ± 4%, and 15 ± 3% at 370, 470, 520, 590, and 660 nm, respectively, highlighting the significant influence of BrC absorption on the radiative imbalance over northern PSEA. Strong and significant associations between BrC light absorption and biomass-burning (BB) organic tracers highlighted the influence of primary BB emissions. The median MACBrC and kBrC values at 370 nm were 2.4 m2 g-1 and 0.12, respectively. The fractional contribution of solar radiation absorbed by BrC relative to BC (mean ± SD) in the 370-950 nm range was estimated to be 34 ± 7%, which can significantly influence the regional radiation budget and consequently atmospheric photochemistry. This study provides valuable information to understand BrC absorption over northern PSEA and can be used in model simulations to reassess the regional climatic impact with greater accuracy.
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Affiliation(s)
- Shantanu Kumar Pani
- Department of Atmospheric Sciences, National Central University, Taoyuan, 32001, Taiwan
| | - Neng-Huei Lin
- Department of Atmospheric Sciences, National Central University, Taoyuan, 32001, Taiwan; Center for Environmental Monitoring and Technology, National Central University, Taoyuan, 32001, Taiwan.
| | - Stephen M Griffith
- Department of Atmospheric Sciences, National Central University, Taoyuan, 32001, Taiwan
| | - Somporn Chantara
- Environmental Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand; Environmental Chemistry Research Laboratory, Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Chung-Te Lee
- Graduate Institute of Environmental Engineering, National Central University, Taoyuan, 32001, Taiwan
| | - Duangduean Thepnuan
- Environmental Chemistry Research Laboratory, Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Ying I Tsai
- Department of Environmental Engineering and Science, Chia Nan University of Pharmacy and Science, Tainan, 71710, Taiwan
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