Articles | Volume 23, issue 22
https://doi.org/10.5194/acp-23-14437-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-23-14437-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
22 Nov 2023
Research article |
| 22 Nov 2023
| 22 Nov 2023
pH dependence of brown-carbon optical properties in cloud water
Christopher J. Hennigan
CORRESPONDING AUTHOR
Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, 21250, USA
Michael McKee
Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, 21250, USA
Vikram Pratap
Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, 21250, USA
Bryanna Boegner
Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, 21250, USA
Jasper Reno
Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, 21250, USA
Lucia Garcia
Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, 21250, USA
Madison McLaren
Department of Chemical, Biochemical and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, 21250, USA
Sara M. Lance
Atmospheric Sciences Research Center (ASRC), University at Albany, Albany, 12226, USA
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Vikram Pratap, Christopher J. Hennigan, Bastian Stieger, Andreas Tilgner, Laurent Poulain, Dominik van Pinxteren, Gerald Spindler, and Hartmut Herrmann
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In this work, we characterize trends in aerosol pH and its controlling factors over the period of 2010 – 2019 at the Melpitz research station in eastern Germany. We find strong trends in aerosol pH and major inorganic species in response to changing emissions. We conduct a detailed thermodynamic analysis of the aerosol system and discuss implications for controlling PM2.5 in the region.
Michael A. Battaglia Jr., Nicholas Balasus, Katherine Ball, Vanessa Caicedo, Ruben Delgado, Annmarie G. Carlton, and Christopher J. Hennigan
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This study characterizes aerosol liquid water content and aerosol pH at a land–water transition site near Baltimore, Maryland. We characterize the effects of unique meteorology associated with the close proximity to the Chesapeake Bay and episodic NH3 events derived from industrial and agricultural sources on aerosol chemistry during the summer. We also examine two events where primary Bay emissions underwent aging in the polluted urban atmosphere.
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Measurements of aerosol and gas composition were carried out at a land–water transition site near Baltimore, MD. Gas-phase ammonia concentrations were highly elevated compared to measurements at a nearby inland site. Our analysis reveals that NH2 was from both industrial and agricultural sources. This had a pronounced effect on aerosol chemical composition at the site, most notably contributing to episodic spikes of aerosol nitrate.
Havala O. T. Pye, Athanasios Nenes, Becky Alexander, Andrew P. Ault, Mary C. Barth, Simon L. Clegg, Jeffrey L. Collett Jr., Kathleen M. Fahey, Christopher J. Hennigan, Hartmut Herrmann, Maria Kanakidou, James T. Kelly, I-Ting Ku, V. Faye McNeill, Nicole Riemer, Thomas Schaefer, Guoliang Shi, Andreas Tilgner, John T. Walker, Tao Wang, Rodney Weber, Jia Xing, Rahul A. Zaveri, and Andreas Zuend
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Acid rain is recognized for its impacts on human health and ecosystems, and programs to mitigate these effects have had implications for atmospheric acidity. Historical measurements indicate that cloud and fog droplet acidity has changed in recent decades in response to controls on emissions from human activity, while the limited trend data for suspended particles indicate acidity may be relatively constant. This review synthesizes knowledge on the acidity of atmospheric particles and clouds.
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The effects of water-soluble organic carbon (WSOC) on aerosol pH were characterized for aqueous-phase particles containing a mixture of inorganics and organics. The ISORROPIA-II and E-AIM models were used in conjunction with AIOMFAC to quantify the effect of organics on aerosol pH through (1) changes to the aerosol liquid water content and (2) changes to the hydrogen ion activity coefficient. The study included both organic acids and nonacids, at RH levels ranging from 70 to 90 %.
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We show that the ion balance and molar ratio methods are unsuitable for use as aerosol pH proxies. Our recommendation is that 1) thermodynamic equilibrium models constrained by both gas and aerosol inputs run in the forward (open) mode, and 2) the phase partitioning of ammonia provides the best predictions of aerosol pH. Given the significance of acidity for numerous chemical processes in the atmosphere, the implications of this study are important and far reaching.
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In this work, we characterize trends in aerosol pH and its controlling factors over the period of 2010 – 2019 at the Melpitz research station in eastern Germany. We find strong trends in aerosol pH and major inorganic species in response to changing emissions. We conduct a detailed thermodynamic analysis of the aerosol system and discuss implications for controlling PM2.5 in the region.
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This work uses chemical transport and box modeling to study the gas- and aqueous-phase production of organic acid concentrations measured in cloud water at the summit of Whiteface Mountain on 1 July 2018. Isoprene was the major source of formic, acetic, and oxalic acid. Gas-phase chemistry greatly underestimated formic and acetic acid, indicating missing sources, while cloud chemistry was a key source of oxalic acid. More studies of organic acids are required to better constrain their sources.
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Atmospheric aqueous chemistry can have profound effects on our environment, as illustrated by historical data from Whiteface Mountain (WFM) that were critical for uncovering the process of acid rain. The current study updates the long-term trends in cloud water composition at WFM for the period 1994 to 2021. We highlight the emergence of a new chemical regime at WFM dominated by organics and ammonium, quite different from the highly acidic regime observed in the past but not necessarily
clean.
Michael A. Battaglia Jr., Nicholas Balasus, Katherine Ball, Vanessa Caicedo, Ruben Delgado, Annmarie G. Carlton, and Christopher J. Hennigan
Atmos. Chem. Phys., 21, 18271–18281, https://doi.org/10.5194/acp-21-18271-2021, https://doi.org/10.5194/acp-21-18271-2021, 2021
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This study characterizes aerosol liquid water content and aerosol pH at a land–water transition site near Baltimore, Maryland. We characterize the effects of unique meteorology associated with the close proximity to the Chesapeake Bay and episodic NH3 events derived from industrial and agricultural sources on aerosol chemistry during the summer. We also examine two events where primary Bay emissions underwent aging in the polluted urban atmosphere.
Nicholas Balasus, Michael A. Battaglia Jr., Katherine Ball, Vanessa Caicedo, Ruben Delgado, Annmarie G. Carlton, and Christopher J. Hennigan
Atmos. Chem. Phys., 21, 13051–13065, https://doi.org/10.5194/acp-21-13051-2021, https://doi.org/10.5194/acp-21-13051-2021, 2021
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Measurements of aerosol and gas composition were carried out at a land–water transition site near Baltimore, MD. Gas-phase ammonia concentrations were highly elevated compared to measurements at a nearby inland site. Our analysis reveals that NH2 was from both industrial and agricultural sources. This had a pronounced effect on aerosol chemical composition at the site, most notably contributing to episodic spikes of aerosol nitrate.
Havala O. T. Pye, Athanasios Nenes, Becky Alexander, Andrew P. Ault, Mary C. Barth, Simon L. Clegg, Jeffrey L. Collett Jr., Kathleen M. Fahey, Christopher J. Hennigan, Hartmut Herrmann, Maria Kanakidou, James T. Kelly, I-Ting Ku, V. Faye McNeill, Nicole Riemer, Thomas Schaefer, Guoliang Shi, Andreas Tilgner, John T. Walker, Tao Wang, Rodney Weber, Jia Xing, Rahul A. Zaveri, and Andreas Zuend
Atmos. Chem. Phys., 20, 4809–4888, https://doi.org/10.5194/acp-20-4809-2020, https://doi.org/10.5194/acp-20-4809-2020, 2020
Short summary
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Acid rain is recognized for its impacts on human health and ecosystems, and programs to mitigate these effects have had implications for atmospheric acidity. Historical measurements indicate that cloud and fog droplet acidity has changed in recent decades in response to controls on emissions from human activity, while the limited trend data for suspended particles indicate acidity may be relatively constant. This review synthesizes knowledge on the acidity of atmospheric particles and clouds.
Michael A. Battaglia Jr., Rodney J. Weber, Athanasios Nenes, and Christopher J. Hennigan
Atmos. Chem. Phys., 19, 14607–14620, https://doi.org/10.5194/acp-19-14607-2019, https://doi.org/10.5194/acp-19-14607-2019, 2019
Short summary
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The effects of water-soluble organic carbon (WSOC) on aerosol pH were characterized for aqueous-phase particles containing a mixture of inorganics and organics. The ISORROPIA-II and E-AIM models were used in conjunction with AIOMFAC to quantify the effect of organics on aerosol pH through (1) changes to the aerosol liquid water content and (2) changes to the hydrogen ion activity coefficient. The study included both organic acids and nonacids, at RH levels ranging from 70 to 90 %.
Jie Zhang, Sara Lance, Jeffrey M. Freedman, Yele Sun, Brian A. Crandall, Xiuli Wei, and James J. Schwab
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Preprint retracted
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The impact of fireworks (FW) events on air quality was studied using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and collocated instruments during the Independence Day (July 4) holiday. The Independence Day FW events resulted in significant increases in both organic and inorganic (potassium, sulfate, chloride) chemical components, and the contribution from different aerosol sources was discussed.
Marwa M. H. El-Sayed, Diana L. Ortiz-Montalvo, and Christopher J. Hennigan
Atmos. Chem. Phys., 18, 1171–1184, https://doi.org/10.5194/acp-18-1171-2018, https://doi.org/10.5194/acp-18-1171-2018, 2018
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We characterized the reversibility of aqSOA formed from isoprene at a location in the eastern United States. WSOCp evaporation with drying was observed systematically throughout the late spring and summer, indicating reversible aqSOA formation. The absolute reversible aqSOA concentrations, as well as the relative amount of reversible aqSOA, increased with decreasing NOx / isoprene ratios, suggesting that IEPOX or other low-NOx oxidation products were responsible for these effects.
C. J. Hennigan, J. Izumi, A. P. Sullivan, R. J. Weber, and A. Nenes
Atmos. Chem. Phys., 15, 2775–2790, https://doi.org/10.5194/acp-15-2775-2015, https://doi.org/10.5194/acp-15-2775-2015, 2015
Short summary
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We show that the ion balance and molar ratio methods are unsuitable for use as aerosol pH proxies. Our recommendation is that 1) thermodynamic equilibrium models constrained by both gas and aerosol inputs run in the forward (open) mode, and 2) the phase partitioning of ammonia provides the best predictions of aerosol pH. Given the significance of acidity for numerous chemical processes in the atmosphere, the implications of this study are important and far reaching.
R. Saleh, C. J. Hennigan, G. R. McMeeking, W. K. Chuang, E. S. Robinson, H. Coe, N. M. Donahue, and A. L. Robinson
Atmos. Chem. Phys., 13, 7683–7693, https://doi.org/10.5194/acp-13-7683-2013, https://doi.org/10.5194/acp-13-7683-2013, 2013
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Subject: Aerosols | Research Activity: Field Measurements | Altitude Range: Troposphere | Science Focus: Chemistry (chemical composition and reactions)
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Biomass-burning aerosol is commonly present in the marine boundary layer over the southeast Atlantic Ocean between June and October. Our research indicates that burning conditions, aerosol transport pathways, and prolonged oxidation processes (heterogeneous and aqueous phases) determine the chemical, microphysical, and optical properties of the boundary layer aerosol. Notably, we find that the aerosol optical properties can be estimated from the chemical properties alone.
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Limited aerosol measurements in the central Arctic hinder our understanding of aerosol–climate interactions in the region. Our year-long observations of aerosol physicochemical properties during the MOSAiC expedition reveal strong seasonal variations in aerosol chemical composition, where the short-term variability is heavily affected by storms in the Arctic. Local wind-generated particles are shown to be an important source of cloud seeds, especially in autumn.
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The chemical composition of brown carbon in the particle and gas phase was determined by mass spectrometry. BrC in the gas phase was mainly controlled by secondary formation and particle-to-gas partitioning. BrC in the particle phase was mainly from secondary formation. This work helps to get a better understanding of diurnal variations and the sources of brown carbon aerosol at a rural location in central Europe.
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We present measurements of the organic composition of ultrafine particles collected from the eastern Amazon, an understudied region that is subjected to increasing human influence. We find that while isoprene chemistry is likely significant for ultrafine-particle growth throughout the year, compounds related to other sources, such as biological-spore emissions and biomass burning, exhibit striking seasonal differences, implying extensive variation in regional ultrafine-particle sources.
Kumiko Goto-Azuma, Yoshimi Ogawa-Tsukagawa, Kaori Fukuda, Koji Fujita, Motohiro Hirabayashi, Remi Dallmayr, Jun Ogata, Nobuhiro Moteki, Tatsuhiro Mori, Sho Ohata, Yutaka Kondo, Makoto Koike, Sumito Matoba, Moe Kadota, Akane Tsushima, Naoko Nagatsuka, and Teruo Aoki
Atmos. Chem. Phys., 25, 657–683, https://doi.org/10.5194/acp-25-657-2025, https://doi.org/10.5194/acp-25-657-2025, 2025
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Monthly ice core records spanning 350 years from Greenland show trends in refractory black carbon (rBC) concentrations and sizes. rBC levels have increased since the 1870s due to the inflow of anthropogenic rBC, with larger diameters than those from biomass burning (BB) rBC. High summer BB rBC peaks may reduce the ice sheet albedo, but BB rBC showed no increase until the early 2000s. These results are vital for validating aerosol and climate models.
Jiayin Li, Tianyu Zhai, Xiaorui Chen, Haichao Wang, Shuyang Xie, Shiyi Chen, Chunmeng Li, Huabin Dong, and Keding Lu
EGUsphere, https://doi.org/10.5194/egusphere-2024-3804, https://doi.org/10.5194/egusphere-2024-3804, 2025
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We directly measured the dinitrogen pentoxide (N2O5) uptake coefficient which critical impact the NOx fate and particulate nitrate formation in a typical highland city, Kunming, in China. We found the performance of current γ(N2O5) parameterizations showed deviations with the varying aerosol liquid water content (ALWC). Such differences would lead to biased estimation on particulate nitrate production potential. Our findings suggest the directions for future studies.
Jishnu Pandamkulangara Kizhakkethil, Zongbo Shi, Anna Bogush, and Ivan Kourtchev
EGUsphere, https://doi.org/10.5194/egusphere-2024-3952, https://doi.org/10.5194/egusphere-2024-3952, 2025
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Pollution with per- and polyfluoroalkyl substances (PFAS) received attention due to their environmental persistence and bioaccumulation. PM10 collected above a scaled-down activated sludge tank treating domestic sewage for a population >10,000 people in the UK were analysed for a range of short-, medium- and long-chain PFAS. Eight PFAS were detected in the PM10. Our results suggest that wastewater treatment processes i.e. activated sludge aeration could aerosolise PFAS into airborne PM.
Mingjie Kang, Mengying Bao, Wenhuai Song, Aduburexiati Abulimiti, Changliu Wu, Fang Cao, Sönke Szidat, and Yanlin Zhang
Atmos. Chem. Phys., 25, 73–91, https://doi.org/10.5194/acp-25-73-2025, https://doi.org/10.5194/acp-25-73-2025, 2025
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Reports on molecular-level knowledge of high-temporal-resolution particulate matter ≤2.5 µm in diameter (PM2.5) on hazy days are limited. We investigated various PM2.5 species and their sources. The results show biomass burning (BB) was the main source of organic carbon. Moreover, BB enhanced fungal spore emissions and secondary aerosol formation. The contribution of non-fossil sources increased with increasing haze pollution, suggesting BB may be an important driver of haze events in winter.
Gregory P. Schill, Karl D. Froyd, Daniel M. Murphy, Christina J. Williamson, Charles A. Brock, Tomás Sherwen, Mat J. Evans, Eric A. Ray, Eric C. Apel, Rebecca S. Hornbrook, Alan J. Hills, Jeff Peischl, Thomas B. Ryerson, Chelsea R. Thompson, Ilann Bourgeois, Donald R. Blake, Joshua P. DiGangi, and Glenn S. Diskin
Atmos. Chem. Phys., 25, 45–71, https://doi.org/10.5194/acp-25-45-2025, https://doi.org/10.5194/acp-25-45-2025, 2025
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Using single-particle mass spectrometry, we show that trace concentrations of bromine and iodine are ubiquitous in remote tropospheric aerosol and suggest that aerosols are an important part of the global reactive iodine budget. Comparisons to a global climate model with detailed iodine chemistry are favorable in the background atmosphere; however, the model cannot replicate our measurements near the ocean surface, in biomass burning plumes, and in the stratosphere.
Zhao Wei, Shohei Hattori, Asuka Tsuruta, Zhuang Jiang, Sakiko Ishino, Koji Fujita, Sumito Matoba, Lei Geng, Alexis Lamothe, Ryu Uemura, Naohiro Yoshida, Joel Savarino, and Yoshinori Iizuka
EGUsphere, https://doi.org/10.5194/egusphere-2024-3937, https://doi.org/10.5194/egusphere-2024-3937, 2024
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Nitrate isotope records in ice cores reveal changes in NOₓ emissions, atmospheric acidity, and oxidation chemistry driven by human activity. However, nitrate in snow can be altered by UV-driven post-depositional processes, making snow accumulation rates critical for preserving these records. This study examines nitrate isotopes in an SE-Dome ice core, where high snow accumulation minimizes these effects, providing a reliable archive of atmospheric nitrogen cycling.
Andreas Aktypis, Dontavious J. Sippial, Christina N. Vasilakopoulou, Angeliki Matrali, Christos Kaltsonoudis, Andrea Simonati, Marco Paglione, Matteo Rinaldi, Stefano Decesari, and Spyros N. Pandis
Atmos. Chem. Phys., 24, 13769–13791, https://doi.org/10.5194/acp-24-13769-2024, https://doi.org/10.5194/acp-24-13769-2024, 2024
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A dual-chamber system was deployed in two different environments (Po Valley, Italy, and Pertouli forest, Greece) to study the potential of ambient air directly injected into the chambers, to form secondary organic aerosol (SOA). In the Po Valley, the system reacts rapidly, forming large amounts of SOA, while in Pertouli the SOA formation chemistry appears to have been practically terminated before the beginning of most experiments, so there is little additional SOA formation potential left.
Jie Zhang, Tianyu Zhu, Alexandra Catena, Yaowei Li, Margaret J. Schwab, Pengfei Liu, Akua Asa-Awuku, and James Schwab
Atmos. Chem. Phys., 24, 13445–13456, https://doi.org/10.5194/acp-24-13445-2024, https://doi.org/10.5194/acp-24-13445-2024, 2024
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This study shows the derived organic aerosol hygroscopicity under high-humidity conditions based on a simple optical scatter monitor system, including two nephelometric monitors (pDR-1500), when the aerosol chemical composition is already known.
Wei Yuan, Ru-Jin Huang, Chao Luo, Lu Yang, Wenjuan Cao, Jie Guo, and Huinan Yang
Atmos. Chem. Phys., 24, 13219–13230, https://doi.org/10.5194/acp-24-13219-2024, https://doi.org/10.5194/acp-24-13219-2024, 2024
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We characterized water-soluble oxidative potential (OP) levels in wintertime PM2.5 in the south and north of Beijing. Our results show that the volume-normalized dithiothreitol (DTTv) in the north was comparable to that in the south, while the mass-normalized dithiothreitol (DTTm) in the north was almost twice that in the south. Traffic-related emissions and biomass burning were the main sources of DTTv in the south, and traffic-related emissions contributed the most to DTTv in the north.
Mingfu Cai, Chenshuo Ye, Bin Yuan, Shan Huang, E Zheng, Suxia Yang, Zelong Wang, Yi Lin, Tiange Li, Weiwei Hu, Wei Chen, Qicong Song, Wei Li, Yuwen Peng, Baoling Liang, Qibin Sun, Jun Zhao, Duohong Chen, Jiaren Sun, Zhiyong Yang, and Min Shao
Atmos. Chem. Phys., 24, 13065–13079, https://doi.org/10.5194/acp-24-13065-2024, https://doi.org/10.5194/acp-24-13065-2024, 2024
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This study investigated the daytime secondary organic aerosol (SOA) formation in urban plumes. We observed a significant daytime SOA formation through gas–particle partitioning when the site was affected by urban plumes. A box model simulation indicated that urban pollutants (nitrogen oxide and volatile organic compounds) could enhance the oxidizing capacity, while the elevated volatile organic compounds were mainly responsible for promoting daytime SOA formation.
Yingjie Shen, Rudra P. Pokhrel, Amy P. Sullivan, Ezra J. T. Levin, Lauren A. Garofalo, Delphine K. Farmer, Wade Permar, Lu Hu, Darin W. Toohey, Teresa Campos, Emily V. Fischer, and Shane M. Murphy
Atmos. Chem. Phys., 24, 12881–12901, https://doi.org/10.5194/acp-24-12881-2024, https://doi.org/10.5194/acp-24-12881-2024, 2024
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The magnitude and evolution of brown carbon (BrC) absorption remain unclear, with uncertainty in climate models. Data from the WE-CAN airborne experiment show that model parameterizations overestimate the mass absorption cross section (MAC) of BrC. Observed decreases in BrC absorption with chemical markers are due to decreasing organic aerosol (OA) mass rather than a decreasing BrC MAC, which is currently implemented in models. Water-soluble BrC contributes 23 % of total absorption at 660 nm.
Qun He, Zhaowen Wang, Houfeng Liu, Pengju Xu, Rongbao Duan, Caihong Xu, Jianmin Chen, and Min Wei
Atmos. Chem. Phys., 24, 12775–12792, https://doi.org/10.5194/acp-24-12775-2024, https://doi.org/10.5194/acp-24-12775-2024, 2024
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Coastal environments provide an ideal setting for investigating the intermixing of terrestrial and marine aerosols. Terrestrial air mass constituted a larger number of microbes from anthropogenic and soil emissions, whereas saprophytic and gut microbes were predominant in marine samples. Mixed air masses indicated a fusion of marine and terrestrial aerosols, characterized by alterations in the ratio of pathogenic and saprophytic microbes when compared to either terrestrial or marine samples.
Rime El Asmar, Zongrun Li, David J. Tanner, Yongtao Hu, Susan O'Neill, L. Gregory Huey, M. Talat Odman, and Rodney J. Weber
Atmos. Chem. Phys., 24, 12749–12773, https://doi.org/10.5194/acp-24-12749-2024, https://doi.org/10.5194/acp-24-12749-2024, 2024
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Prescribed burning is an important method for managing ecosystems and preventing wildfires. However, smoke from prescribed fires can have a significant impact on air quality. Here, using a network of fixed sites and sampling throughout an extended prescribed burning period in 2 different years, we characterize emissions and evolutions of up to 8 h of PM2.5 mass, black carbon (BC), and brown carbon (BrC) in smoke from burning of forested lands in the southeastern USA.
Matthew Boyer, Diego Aliaga, Lauriane L. J. Quéléver, Silvia Bucci, Hélène Angot, Lubna Dada, Benjamin Heutte, Lisa Beck, Marina Duetsch, Andreas Stohl, Ivo Beck, Tiia Laurila, Nina Sarnela, Roseline C. Thakur, Branka Miljevic, Markku Kulmala, Tuukka Petäjä, Mikko Sipilä, Julia Schmale, and Tuija Jokinen
Atmos. Chem. Phys., 24, 12595–12621, https://doi.org/10.5194/acp-24-12595-2024, https://doi.org/10.5194/acp-24-12595-2024, 2024
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We analyze the seasonal cycle and sources of gases that are relevant for the formation of aerosol particles in the central Arctic. Since theses gases can form new particles, they can influence Arctic climate. We show that the sources of these gases are associated with changes in the Arctic environment during the year, especially with respect to sea ice. Therefore, the concentration of these gases will likely change in the future as the Arctic continues to warm.
Binyu Xiao, Fan Zhang, Zeyu Liu, Yan Zhang, Rui Li, Can Wu, Xinyi Wan, Yi Wang, Yubao Chen, Yong Han, Min Cui, Libo Zhang, Yingjun Chen, and Gehui Wang
EGUsphere, https://doi.org/10.5194/egusphere-2024-3433, https://doi.org/10.5194/egusphere-2024-3433, 2024
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Intermediate/semi-volatile organic compounds in both gas and particle phases from ship exhausts are enhanced due to the switch of fuels from low-sulfur to ultra-low-sulfur. The findings indicate that optimization is necessary for the forthcoming global implementation of an ultra-low-sulfur oil policy. Besides, we find that organic diagnostic markers of hopanes, in conjunction with the ratio of octadecanoic to tetradecanoic could be considered as potential tracers for HFO exhausts.
Haley M. Royer, Michael T. Sheridan, Hope E. Elliott, Nurun Nahar Lata, Zezhen Cheng, Swarup China, Zihua Zhu, Andrew P. Ault, and Cassandra J. Gaston
EGUsphere, https://doi.org/10.5194/egusphere-2024-3288, https://doi.org/10.5194/egusphere-2024-3288, 2024
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Saharan dust transported across the Atlantic to the Caribbean, South America, and North America is hypothesized to undergo chemical processing by inorganic and organic acids that enhances cloud droplet formation, nutrient availability, and reflectivity of. In this study, chemical analysis performed on African dust deposited over Barbados shows that acid tracers are found mostly on sea salt and smoke particles, rather than dust, indicating that dust particles undergo minimal chemical processing.
Imad El Haddad, Danielle Vienneau, Kaspar R. Daellenbach, Robin Modini, Jay G. Slowik, Abhishek Upadhyay, Petros N. Vasilakos, David Bell, Kees de Hoogh, and Andre S. H. Prevot
Atmos. Chem. Phys., 24, 11981–12011, https://doi.org/10.5194/acp-24-11981-2024, https://doi.org/10.5194/acp-24-11981-2024, 2024
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This opinion paper explores how advances in aerosol science inform our understanding of the health impacts of outdoor particulate pollution. We advocate for a shift in the way we target PM pollution, focusing on the most harmful anthropogenic emissions. We highlight key observations, modelling developments, and emission measurements needed to achieve this shift.
Pramod Kumar, Khushboo Sharma, Ankita Malu, Rajeev Rajak, Aparna Gupta, Bidyutjyoti Baruah, Shailesh Yadav, Thupstan Angchuk, Jayant Sharma, Rakesh Kumar Ranjan, Anil Kumar Misra, and Nishchal Wanjari
Atmos. Chem. Phys., 24, 11585–11601, https://doi.org/10.5194/acp-24-11585-2024, https://doi.org/10.5194/acp-24-11585-2024, 2024
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This work monitors and assesses air pollution, especially black and brown carbon, its controlling factor, and its effect on the environment of Sikkim Himalayan region. The huge urban sprawl in recent decades has led to regional human-induced air pollution in the region. Black carbon was highest in April 2021 and March 2022, exceeding the WHO limit. The monsoon season causes huge rainfall over the region, which reduces the pollutants by scavenging (rainout and washout).
Maria P. Velásquez-García, K. Santiago Hernández, James A. Vergara-Correa, Richard J. Pope, Miriam Gómez-Marín, and Angela M. Rendón
Atmos. Chem. Phys., 24, 11497–11520, https://doi.org/10.5194/acp-24-11497-2024, https://doi.org/10.5194/acp-24-11497-2024, 2024
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In the Aburrá Valley, northern South America, local emissions determine air quality conditions. However, we found that external sources, such as regional fires, Saharan dust, and volcanic emissions, increase particulate concentrations and worsen chemical composition by introducing elements like heavy metals. Dry winds and source variability contribute to seasonal influences on these events. This study assesses the air quality risks posed by such events, which can affect broad regions worldwide.
Diana L. Pereira, Chiara Giorio, Aline Gratien, Alexander Zherebker, Gael Noyalet, Servanne Chevaillier, Stéphanie Alage, Elie Almarj, Antonin Bergé, Thomas Bertin, Mathieu Cazaunau, Patrice Coll, Ludovico Di Antonio, Sergio Harb, Johannes Heuser, Cécile Gaimoz, Oscar Guillemant, Brigitte Language, Olivier Lauret, Camilo Macias, Franck Maisonneuve, Bénédicte Picquet-Varrault, Raquel Torres, Sylvain Triquet, Pascal Zapf, Lelia Hawkins, Drew Pronovost, Sydney Riley, Pierre-Marie Flaud, Emilie Perraudin, Pauline Pouyes, Eric Villenave, Alexandre Albinet, Olivier Favez, Robin Aujay-Plouzeau, Vincent Michoud, Christopher Cantrell, Manuela Cirtog, Claudia Di Biagio, Jean-François Doussin, and Paola Formenti
EGUsphere, https://doi.org/10.5194/egusphere-2024-3015, https://doi.org/10.5194/egusphere-2024-3015, 2024
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In order to study aerosols in environments influenced by anthropogenic and biogenic emissions, we performed analysis of samples collected during ACROSS (Atmospheric Chemistry Of the Suburban Forest) campaign in the summer 2022 in the Paris greater area. After analysis of the chemical composition by means of total carbon determination and high resolution mass spectrometry, this work highlights the influence of anthropogenic inputs into the chemical composition of both urban and forested areas.
Meng Wang, Qiyuan Wang, Steven Sai Hang Ho, Jie Tian, Yong Zhang, Shun-cheng Lee, and Junji Cao
Atmos. Chem. Phys., 24, 11175–11189, https://doi.org/10.5194/acp-24-11175-2024, https://doi.org/10.5194/acp-24-11175-2024, 2024
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We studied nitrogen-containing organic compounds (NOCs) in particulate matter <2.5 µm particles on the southeastern Tibetan Plateau. We found that biomass burning and transboundary transport are the main sources of NOCs in the high-altitude area. Understanding these aerosol sources informs how they add to regional and potentially global climate changes. Our findings could help shape effective environmental policies to enhance air quality and address climate impacts in this sensitive region.
Kimmo Teinilä, Sanna Saarikoski, Henna Lintusaari, Teemu Lepistö, Petteri Marjanen, Minna Aurela, Heidi Hellén, Toni Tykkä, Markus Lampimäki, Janne Lampilahti, Luis Barreira, Timo Mäkelä, Leena Kangas, Juha Hatakka, Sami Harni, Joel Kuula, Jarkko V. Niemi, Harri Portin, Jaakko Yli-Ojanperä, Ville Niemelä, Milja Jäppi, Katrianne Lehtipalo, Joonas Vanhanen, Liisa Pirjola, Hanna E. Manninen, Tuukka Petäjä, Topi Rönkkö, and Hilkka Timonen
EGUsphere, https://doi.org/10.5194/egusphere-2024-2235, https://doi.org/10.5194/egusphere-2024-2235, 2024
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Physical and chemical properties of particulate matter and concentrations of trace gases were measured in a street canyon in Helsinki, Finland and an urban background site in January–February 2022 to investigate the effect of wintertime conditions on pollutants. State-of-the-art instruments, a mobile laboratory was used, and the measurement data was further analysed with modelling tools like positive matrix factorization (PMF) and pollution detection algorithm (PDA).
Jinbo Wang, Jiaping Wang, Yuxuan Zhang, Tengyu Liu, Xuguang Chi, Xin Huang, Dafeng Ge, Shiyi Lai, Caijun Zhu, Lei Wang, Qiaozhi Zha, Ximeng Qi, Wei Nie, Congbin Fu, and Aijun Ding
Atmos. Chem. Phys., 24, 11063–11080, https://doi.org/10.5194/acp-24-11063-2024, https://doi.org/10.5194/acp-24-11063-2024, 2024
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In this study, we found large spatial discrepancies in the physical and chemical properties of black carbon over the Tibetan Plateau (TP). Elevated anthropogenic emissions from low-altitude regions can significantly change the mass concentration, mixing state and chemical composition of black-carbon-containing aerosol in the TP region, further altering its light absorption ability. Our study emphasizes the vulnerability of remote plateau regions to intense anthropogenic influences.
Liyuan Zhou, Qianyun Liu, Christian M. Salvador, Michael Le Breton, Mattias Hallquist, Jian Zhen Yu, Chak K. Chan, and Åsa M. Hallquist
Atmos. Chem. Phys., 24, 11045–11061, https://doi.org/10.5194/acp-24-11045-2024, https://doi.org/10.5194/acp-24-11045-2024, 2024
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Our research on city bus emissions reveals that alternative fuels (compressed natural gas and biofuels) reduce fresh particle emissions compared to diesel. However, all fuels lead to secondary air pollution. Aiming at guiding better environmental policies, we studied 76 buses using advanced emission measurement techniques. This work sheds light on the complex effects of bus fuels on urban air quality, emphasizing the need for comprehensive evaluations of future transportation technologies.
Xu Yang, Fobang Liu, Shuqi Yang, Yuling Yang, Yanan Wang, Jingjing Li, Mingyu Zhao, Zhao Wang, Kai Wang, Chi He, and Haijie Tong
Atmos. Chem. Phys., 24, 11029–11043, https://doi.org/10.5194/acp-24-11029-2024, https://doi.org/10.5194/acp-24-11029-2024, 2024
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A study in the rural North China Plain showed environmentally persistent free radicals (EPFRs) in atmospheric particulate matter (PM), with a notable water-soluble fraction likely from atmospheric oxidation during transport. Significant positive correlations between EPFRs and the water-soluble oxidative potential of PM2.5 were found, primarily attributable to the water-soluble fractions of EPFRs. These findings emphasize understanding EPFRs' atmospheric evolution for climate and health impacts.
Genevieve Rose Lorenzo, Luke D. Ziemba, Avelino F. Arellano, Mary C. Barth, Ewan C. Crosbie, Joshua P. DiGangi, Glenn S. Diskin, Richard Ferrare, Miguel Ricardo A. Hilario, Michael A. Shook, Simone Tilmes, Jian Wang, Qian Xiao, Jun Zhang, and Armin Sorooshian
EGUsphere, https://doi.org/10.5194/egusphere-2024-2604, https://doi.org/10.5194/egusphere-2024-2604, 2024
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Novel aerosol hygroscopicity analysis of CAMP2Ex field campaign data show low aerosol hygroscopicity values in Southeast Asia. Organic carbon from smoke decreases hygroscopicity to levels more like those in continental than in polluted marine regions. Hygroscopicity changes at cloud level demonstrate how surface particles impact clouds in the region affecting model representation of aerosol and cloud interactions in similar polluted marine regions with high organic carbon emissions.
Kirsten N. Fossum, Chunshui Lin, Niall O'Sullivan, Lu Lei, Stig Hellebust, Darius Ceburnis, Aqeel Afzal, Anja Tremper, David Green, Srishti Jain, Steigvilė Byčenkienė, Colin O'Dowd, John Wenger, and Jurgita Ovadnevaite
Atmos. Chem. Phys., 24, 10815–10831, https://doi.org/10.5194/acp-24-10815-2024, https://doi.org/10.5194/acp-24-10815-2024, 2024
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The chemical composition and sources of submicron aerosol in the Dublin Port area were investigated over a month-long campaign. Two distinct types of ship emissions were identified and characterised: sulfate-rich plumes from the use of heavy fuel oil with scrubbers and organic-rich plumes from the use of low-sulfur fuels. The latter were more frequent, emitting double the particle number and having a typical V / Ni ratio for ship emission.
Lise Le Berre, Brice Temime-Roussel, Grazia Maria Lanzafame, Barbara D’Anna, Nicolas Marchand, Stéphane Sauvage, Marvin Dufresne, Liselotte Tinel, Thierry Leonardis, Joel Ferreira de Brito, Alexandre Armengaud, Grégory Gille, Ludovic Lanzi, Romain Bourjot, and Henri Wortham
EGUsphere, https://doi.org/10.5194/egusphere-2024-2903, https://doi.org/10.5194/egusphere-2024-2903, 2024
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A summer campaign in a Mediterranean port examined pollution caused by ships. Two stations in the port measured pollution levels and captured over 350 ship plumes to study their chemical composition. Results showed that pollution levels, like ultra-fine particles, were higher in the port than in the city and offer a strong support to improve emission inventories. These findings may also serve as reference for assessing the benefits of a Sulphur Emission Control Area in the Mediterranean in 2025.
Xiao He, Xuan Zheng, Shuwen Guo, Lewei Zeng, Ting Chen, Bohan Yang, Shupei Xiao, Qiongqiong Wang, Zhiyuan Li, Yan You, Shaojun Zhang, and Ye Wu
Atmos. Chem. Phys., 24, 10655–10666, https://doi.org/10.5194/acp-24-10655-2024, https://doi.org/10.5194/acp-24-10655-2024, 2024
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This study introduces an innovative method for identifying and quantifying complex organic vapors and aerosols. By combining advanced analytical techniques and new algorithms, we categorized thousands of compounds from heavy-duty diesel vehicles and ambient air and highlighted specific tracers for emission sources. The innovative approach enhances peak identification, reduces quantification uncertainties, and offers new insights for air quality management and atmospheric chemistry.
Emmanuel Chevassus, Kirsten N. Fossum, Darius Ceburnis, Lu Lei, Chunshui Lin, Wei Xu, Colin D. O’ Dowd, and Jurgita Ovadnevaite
EGUsphere, https://doi.org/10.5194/egusphere-2024-2890, https://doi.org/10.5194/egusphere-2024-2890, 2024
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This study presents the first source apportionment of OA at Mace Head via high-resolution mass spectrometry. Introducing transfer entropy as a novel method reveals that aged OA originate from open ocean ozonolysis and local peat burning oxidation. Methanesulphonic acid OA and primary marine OA both mirror phytoplankton activity as observed with their chemical makeup, with MSA-OA closely tied to coccolithophore blooms and PMOA linked to diatoms, chlorophytes, and cyanobacteria.
Yu Xu, Tang Liu, Yi-Jia Ma, Qi-Bin Sun, Hong-Wei Xiao, Hao Xiao, Hua-Yun Xiao, and Cong-Qiang Liu
Atmos. Chem. Phys., 24, 10531–10542, https://doi.org/10.5194/acp-24-10531-2024, https://doi.org/10.5194/acp-24-10531-2024, 2024
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This study investigates the characteristics of aminiums and ammonium in PM2.5 on clean and polluted winter days in 11 Chinese cities, highlighting the possibility of the competitive uptake of ammonia versus amines on acidic aerosols or the displacement of aminiums by ammonia under high-ammonia conditions. The overall results deepen the understanding of the spatiotemporal differences in aminium characteristics and formation in China.
Cassidy Soloff, Taiwo Ajayi, Yonghoon Choi, Ewan C. Crosbie, Joshua P. DiGangi, Glenn S. Diskin, Marta A. Fenn, Richard A. Ferrare, Francesca Gallo, Johnathan W. Hair, Miguel Ricardo A. Hilario, Simon Kirschler, Richard H. Moore, Taylor J. Shingler, Michael A. Shook, Kenneth L. Thornhill, Christiane Voigt, Edward L. Winstead, Luke D. Ziemba, and Armin Sorooshian
Atmos. Chem. Phys., 24, 10385–10408, https://doi.org/10.5194/acp-24-10385-2024, https://doi.org/10.5194/acp-24-10385-2024, 2024
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Using aircraft measurements over the northwestern Atlantic between the US East Coast and Bermuda and trajectory modeling of continental outflow, we identify trace gas and particle properties that exhibit gradients with offshore distance and quantify these changes with high-resolution measurements of concentrations and particle chemistry, size, and scattering properties. This work furthers our understanding of the complex interactions between continental and marine environments.
Alex Rowell, James Brean, David C. S. Beddows, Zongbo Shi, Avinash Kumar, Matti Rissanen, Miikka Dal Maso, Peter Mettke, Kay Weinhold, Maik Merkel, and Roy M. Harrison
Atmos. Chem. Phys., 24, 10349–10361, https://doi.org/10.5194/acp-24-10349-2024, https://doi.org/10.5194/acp-24-10349-2024, 2024
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Ions enhance the formation and growth rates of new particles, affecting the Earth's radiation budget. Despite these effects, there is little published data exploring the sources of ions in the urban environment and their role in new particle formation (NPF). Here we show that natural ion sources dominate in urban environments, while traffic is a secondary source. Ions contribute up to 12.7 % of the formation rate of particles, indicating that they are important for forming urban PM.
Yuan Cheng, Xu-bing Cao, Sheng-qiang Zhu, Zhi-qing Zhang, Jiu-meng Liu, Hong-liang Zhang, Qiang Zhang, and Ke-bin He
Atmos. Chem. Phys., 24, 9869–9883, https://doi.org/10.5194/acp-24-9869-2024, https://doi.org/10.5194/acp-24-9869-2024, 2024
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The agreement between observational and modeling results is essential for the development of efficient air pollution control strategies. Here we constrained the modeling results of carbonaceous aerosols by field observation in Northeast China, a historically overlooked but recently targeted region of national clean-air actions. Our study suggested that the simulation of agricultural fire emissions and secondary organic aerosols remains challenging.
Yuan Dai, Junfeng Wang, Houjun Wang, Shijie Cui, Yunjiang Zhang, Haiwei Li, Yun Wu, Ming Wang, Eleonora Aruffo, and Xinlei Ge
Atmos. Chem. Phys., 24, 9733–9748, https://doi.org/10.5194/acp-24-9733-2024, https://doi.org/10.5194/acp-24-9733-2024, 2024
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Short-term strict emission control can improve air quality, but its effectiveness needs assessment. During the 2021 summer COVID-19 lockdown in Yangzhou, we found that PM2.5 levels did not decrease despite reduced primary emissions. Aged black-carbon particles increased substantially due to higher O3 levels and transported pollutants. High humidity and low wind also played key roles. The results highlight the importance of a regionally balanced control strategy for future air quality management.
Xinya Liu, Diego Alves Gouveia, Bas Henzing, Arnoud Apituley, Arjan Hensen, Danielle van Dinther, Rujin Huang, and Ulrike Dusek
Atmos. Chem. Phys., 24, 9597–9614, https://doi.org/10.5194/acp-24-9597-2024, https://doi.org/10.5194/acp-24-9597-2024, 2024
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The vertical distribution of aerosol optical properties is important for their effect on climate. This is usually measured by lidar, which has limitations, most notably the assumption of a lidar ratio. Our study shows that routine surface-level aerosol measurements are able to predict this lidar ratio reasonably well within the lower layers of the atmosphere and thus provide a relatively simple and cost-effective method to improve lidar measurements.
Weiqi Xu, Ye Kuang, Wanyun Xu, Zhiqiang Zhang, Biao Luo, Xiaoyi Zhang, Jiangchuang Tao, Hongqin Qiao, Li Liu, and Yele Sun
Atmos. Chem. Phys., 24, 9387–9399, https://doi.org/10.5194/acp-24-9387-2024, https://doi.org/10.5194/acp-24-9387-2024, 2024
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We deployed an advanced aerosol–fog sampling system at a rural site in the North China Plain to investigate impacts of aerosol hygroscopic growth and activation on the physicochemical properties of submicron aerosols. Observed results highlighted remarkably different aqueous processing of primary and secondary submicron aerosol components under distinct ambient relative humidity (RH) conditions and that RH levels significantly impact aerosol sampling through the aerosol swelling effect.
Can Wu, Xiaodi Liu, Ke Zhang, Si Zhang, Cong Cao, Jianjun Li, Rui Li, Fan Zhang, and Gehui Wang
Atmos. Chem. Phys., 24, 9263–9275, https://doi.org/10.5194/acp-24-9263-2024, https://doi.org/10.5194/acp-24-9263-2024, 2024
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Brown carbon (BrC) is prevalent in the troposphere and can efficiently absorb solar and terrestrial radiation. Our observations show that the enhanced light absorption of BrC relative to black carbon at the tropopause can be attributed to the formation of nitrogen-containing organic compounds through the aqueous-phase reactions of carbonyls with ammonium.
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Short summary
This study characterized the optical properties of light-absorbing organic compounds, called brown carbon (BrC), in atmospheric cloud water samples. In all samples, light absorption by BrC increased linearly with increasing pH. There was variability in the sensitivity of the absorption–pH relationship, depending on the degree of influence from fire emissions. Overall, these results show that the climate forcing of BrC is quite strongly affected by its pH-dependent absorption.
This study characterized the optical properties of light-absorbing organic compounds, called...
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