Articles | Volume 18, issue 3
Research article 08 Feb 2018
Research article | 08 Feb 2018
Investigating biomass burning aerosol morphology using a laser imaging nephelometer
Katherine M. Manfred et al.
Caroline C. Womack, Katherine M. Manfred, Nicholas L. Wagner, Gabriela Adler, Alessandro Franchin, Kara D. Lamb, Ann M. Middlebrook, Joshua P. Schwarz, Charles A. Brock, Steven S. Brown, and Rebecca A. Washenfelder
Atmos. Chem. Phys., 21, 7235–7252,Short summary
Microscopic particles interact with sunlight and affect the earth's climate in ways that are not fully understood. Aerosols from wildfire smoke present particular challenges due to their complexity in shape and composition. We demonstrate that we can experimentally measure aerosol optical properties for many types of smoke particles, using measurements of smoke from controlled burns, but that the method does not work well for smoke with high soot content.
Adam T. Ahern, Frank Erdesz, Nicholas L. Wagner, Charles A. Brock, Ming Lyu, Kyra Slovacek, Richard H. Moore, Elizabeth B. Wiggins, and Daniel M. Murphy
Atmos. Meas. Tech. Discuss.,
Preprint under review for AMTShort summary
Particles in the atmosphere play a significant role in climate change by scattering light back into space, reducing the amount of energy available to be absorbed by greenhouse gases. We built a new instrument to measure what direction light is scattered by particles, e.g. wildfire smoke. This is important because, depending on the angle of the sun, some particles scatter light into space (cooling the planet), but some light is also scattered towards the Earth (not cooling the planet.)
Richard H. Moore, Elizabeth B. Wiggins, Adam T. Ahern, Stephen Zimmerman, Lauren Montgomery, Pedro Campuzano Jost, Claire E. Robinson, Luke D. Ziemba, Edward L. Winstead, Bruce E. Anderson, Charles A. Brock, Matthew D. Brown, Gao Chen, Ewan C. Crosbie, Hongyu Guo, Jose L. Jimenez, Carolyn E. Jordan, Ming Lyu, Benjamin A. Nault, Nicholas E. Rothfuss, Kevin J. Sanchez, Melinda Schueneman, Taylor J. Shingler, Michael A. Shook, Kenneth L. Thornhill, Nicholas L. Wagner, and Jian Wang
Atmos. Meas. Tech., 14, 4517–4542,Short summary
Atmospheric particles are everywhere and exist in a range of sizes, from a few nanometers to hundreds of microns. Because particle size determines the behavior of chemical and physical processes, accurately measuring particle sizes is an important and integral part of atmospheric field measurements! Here, we discuss the performance of two commonly used particle sizers and how changes in particle composition and optical properties may result in sizing uncertainties, which we quantify.
Marco Zanatta, Andreas Herber, Zsófia Jurányi, Oliver Eppers, Johannes Schneider, and Joshua P. Schwarz
Atmos. Chem. Phys., 21, 9329–9342,Short summary
Saline snow samples were collected from the sea ice in the Fram Strait. Laboratory experiments revealed that sea salt can bias the quantification of black carbon with a laser-induced incandescence technique. The maximum underestimation was quantified to reach values of 80 %–90 %. This salt-induced interference is reported here for the first time and should be considered in future studies aiming to quantify black carbon in snow in marine environments.
Christina J. Williamson, Agnieszka Kupc, Andrew Rollins, Jan Kazil, Karl D. Froyd, Eric A. Ray, Daniel M. Murphy, Gregory P. Schill, Jeff Peischl, Chelsea Thompson, Ilann Bourgeois, Thomas B. Ryerson, Glenn S. Diskin, Joshua P. DiGangi, Donald R. Blake, Thao Paul V. Bui, Maximilian Dollner, Bernadett Weinzierl, and Charles A. Brock
Atmos. Chem. Phys., 21, 9065–9088,Short summary
Aerosols in the stratosphere influence climate by scattering and absorbing sunlight and through chemical reactions occurring on the particles’ surfaces. We observed more nucleation mode aerosols (small aerosols, with diameters below 12 nm) in the mid- and high-latitude lowermost stratosphere (8–13 km) in the Northern Hemisphere (NH) than in the Southern Hemisphere. The most likely cause of this is aircraft emissions, which are concentrated in the NH at similar altitudes to our observations.
Daniel M. Murphy, Karl D. Froyd, Ilann Bourgeois, Charles A. Brock, Agnieszka Kupc, Jeff Peischl, Gregory P. Schill, Chelsea R. Thompson, Christina J. Williamson, and Pengfei Yu
Atmos. Chem. Phys., 21, 8915–8932,Short summary
New measurements in the lower stratosphere highlight differences between particles that originated in the troposphere or the stratosphere. The stratospheric-origin particles have relatively large radiative effects because they are at nearly the optimum diameter for light scattering. The tropospheric particles contribute significantly to surface area. These and other chemical and physical properties are then extended to study the implications if material were to be added to the stratosphere.
Jin Liao, Glenn M. Wolfe, Reem A. Hannun, Jason M. St. Clair, Thomas F. Hanisco, Jessica B. Gilman, Aaron Lamplugh, Vanessa Selimovic, Glenn S. Diskin, John B. Nowak, Hannah S. Halliday, Joshua P. DiGangi, Samuel R. Hall, Kirk Ullmann, Christopher D. Holmes, Charles H. Fite, Anxhelo Agastra, Thomas B. Ryerson, Jeff Peischl, Ilann Bourgeois, Carsten Warneke, Matthew M. Coggon, Georgios I. Gkatzelis, Kanako Sekimoto, Alan Fried, Dirk Richter, Petter Weibring, Eric C. Apel, Rebecca S. Hornbrook, Steven S. Brown, Caroline C. Womack, Michael A. Robinson, Rebecca A. Washenfelder, Patrick R. Veres, and J. Andrew Neuman
Atmos. Chem. Phys. Discuss.,
Revised manuscript under review for ACPShort summary
Formaldehyde is an important oxidant precursor and affects the formation of O3 and other secondary pollutants in wildfire plumes. We disentangle the processes controlling HCHO evolution from a variety of wildfire plumes sampled by NASA DC-8 during FIREX-AQ field campaign. We find that OH abundance rather than normalized OH reactivity is the main driver of fire-to-fire variability in HCHO secondary production and estimate an effective HCHO yield per VOC molecule oxidized in wildfire plumes.
Amy Hrdina, Jennifer G. Murphy, Anna Gannet Hallar, John C. Lin, Alexander Moravek, Ryan Bares, Ross C. Petersen, Alessandro Franchin, Ann M. Middlebrook, Lexie Goldberger, Ben H. Lee, Munkh Baasandorj, and Steven S. Brown
Atmos. Chem. Phys., 21, 8111–8126,Short summary
Wintertime air pollution in the Salt Lake Valley is primarily composed of ammonium nitrate, which is formed when gas-phase ammonia and nitric acid react. The major point in this work is that the chemical composition of snow tells a very different story to what we measured in the atmosphere. With the dust–sea salt cations observed in PM2.5 and particle sizing data, we can estimate how much nitric acid may be lost to dust–sea salt that is not accounted for and how much more PM2.5 this could form.
Linghan Zeng, Amy P. Sullivan, Rebecca A. Washenfelder, Jack Dibb, Eric Scheuer, Teresa L. Campos, Joseph M. Katich, Ezra Levin, Michael A. Robinson, and Rodney J. Weber
Atmos. Meas. Tech. Discuss.,
Revised manuscript accepted for AMTShort summary
Three online systems for measuring water-soluble brown carbon are compared. A mist chamber and two different particle-into-liquid samplers were deployed on separate research aircraft targeting wildfires and followed a similar detection method using a long path liquid waveguide with a spectrometer to measure the light absorption from 300 to 700 nm. Detection limits, signal hysteresis and other sampling issues are compared, and further improvements of these liquid-based systems are provided.
Caroline C. Womack, Katherine M. Manfred, Nicholas L. Wagner, Gabriela Adler, Alessandro Franchin, Kara D. Lamb, Ann M. Middlebrook, Joshua P. Schwarz, Charles A. Brock, Steven S. Brown, and Rebecca A. Washenfelder
Atmos. Chem. Phys., 21, 7235–7252,Short summary
Microscopic particles interact with sunlight and affect the earth's climate in ways that are not fully understood. Aerosols from wildfire smoke present particular challenges due to their complexity in shape and composition. We demonstrate that we can experimentally measure aerosol optical properties for many types of smoke particles, using measurements of smoke from controlled burns, but that the method does not work well for smoke with high soot content.
Li Zhang, Georg Grell, Stuart McKeen, Ravan Ahmadov, Karl Froyd, and Daniel Murphy
Geosci. Model Dev. Discuss.,
Preprint under review for GMDShort summary
Applying the chemistry package from WRF-Chem into the Flow-following finite-volume Icosahedra Model, we essentially make it possible to explore the importance of different levels of complexity in gas and aerosol chemistry, as well as in physics parameterizations on the interaction processes in global modeling systems. The model performance validated by the Atmospheric Tomography Mission aircraft measurements in 2016 summer shows good performance in capturing the aerosol and gas-phase tracers.
Zachary C. J. Decker, Michael A. Robinson, Kelley C. Barsanti, Ilann Bourgeois, Matthew M. Coggon, Joshua P. DiGangi, Glenn S. Diskin, Frank M. Flocke, Alessandro Franchin, Carley D. Fredrickson, Samuel R. Hall, Hannah Halliday, Christopher D. Holmes, L. Gregory Huey, Young Ro Lee, Jakob Lindaas, Ann M. Middlebrook, Denise D. Montzka, Richard H. Moore, J. Andrew Neuman, John B. Nowak, Brett B. Palm, Jeff Peischl, Pamela S. Rickly, Andrew W. Rollins, Thomas B. Ryerson, Rebecca H. Schwantes, Lee Thornhill, Joel A. Thornton, Geoff S. Tyndall, Kirk Ullmann, Paul Van Rooy, Patrick R. Veres, Andrew J. Weinheimer, Elizabeth Wiggins, Edward Winstead, Caroline Womack, and Steven S. Brown
Atmos. Chem. Phys. Discuss.,
Preprint under review for ACPShort summary
To understand air quality impacts from wildfire smoke we need an accurate picture of how wildfire smoke changes chemically both day and night as sunlight changes the chemistry of smoke. We present a chemical analysis of wildfire smoke as it changes from midday through the night. We use aircraft observations from the FIREX-AQ field campaign with a chemical box model. We find that even under sunlight typical “nighttime” chemistry thrives and controls the fate of key smoke plume chemical processes.
Charles A. Brock, Karl D. Froyd, Maximilian Dollner, Christina J. Williamson, Gregory Schill, Daniel M. Murphy, Nicholas J. Wagner, Agnieszka Kupc, Jose L. Jimenez, Pedro Campuzano-Jost, Benjamin A. Nault, Jason C. Schroder, Douglas A. Day, Derek J. Price, Bernadett Weinzierl, Joshua P. Schwarz, Joseph M. Katich, Linghan Zeng, Rodney Weber, Jack Dibb, Eric Scheuer, Glenn S. Diskin, Joshua P. DiGangi, ThaoPaul Bui, Jonathan M. Dean-Day, Chelsea R. Thompson, Jeff Peischl, Thomas B. Ryerson, Ilann Bourgeois, Bruce C. Daube, Róisín Commane, and Steven C. Wofsy
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
The Atmospheric Tomography Mission was an airborne study that mapped the chemical composition of the remote atmosphere. From this, we developed a comprehensive description of aerosol properties that provides unique, global-scale dataset against which models can be compared. The data show the polluted nature of the remote atmosphere in the Northern Hemisphere, and quantify the contributions of sea salt, dust, soot, biomass burning particles, and pollution particles to the haziness of the sky.
Lawrence I. Kleinman, Arthur J. Sedlacek III, Kouji Adachi, Peter R. Buseck, Sonya Collier, Manvendra K. Dubey, Anna L. Hodshire, Ernie Lewis, Timothy B. Onasch, Jeffery R. Pierce, John Shilling, Stephen R. Springston, Jian Wang, Qi Zhang, Shan Zhou, and Robert J. Yokelson
Atmos. Chem. Phys., 20, 13319–13341,Short summary
Aerosols from wildfires affect the Earth's temperature by absorbing light or reflecting it back into space. This study investigates time-dependent chemical, microphysical, and optical properties of aerosols generated by wildfires in the Pacific Northwest, USA. Wildfire smoke plumes were traversed by an instrumented aircraft at locations near the fire and up to 3.5 h travel time downwind. Although there was no net aerosol production, aerosol particles grew and became more efficient scatters.
Melodie Lao, Leigh R. Crilley, Leyla Salehpoor, Teles C. Furlani, Ilann Bourgeois, J. Andrew Neuman, Andrew W. Rollins, Patrick R. Veres, Rebecca A. Washenfelder, Caroline C. Womack, Cora J. Young, and Trevor C. VandenBoer
Atmos. Meas. Tech., 13, 5873–5890,Short summary
Nitrous acid (HONO) is a key intermediate in the generation of oxidants and fate of nitrogen oxides in the atmosphere. High-purity calibration sources that produce stable atmospherically relevant levels under field conditions have not been made to date, reducing measurement accuracy. In this study a simple salt-coated tube humidified with water vapor is demonstrated to produce pure stable low levels of HONO, with modifications allowing the generation of higher amounts.
James M. Roberts, Chelsea E. Stockwell, Robert J. Yokelson, Joost de Gouw, Yong Liu, Vanessa Selimovic, Abigail R. Koss, Kanako Sekimoto, Matthew M. Coggon, Bin Yuan, Kyle J. Zarzana, Steven S. Brown, Cristina Santin, Stefan H. Doerr, and Carsten Warneke
Atmos. Chem. Phys., 20, 8807–8826,Short summary
We measured total reactive nitrogen, Nr, in lab fires from western North American fuels, along with measurements of individual nitrogen compounds. We measured the amount of N that gets converted to inactive compounds (avg. 70 %), and the amount that is accounted for by individual species (85 % of remaining N). We provide guidelines for how the reactive nitrogen is distributed among individual compounds such as NOx and ammonia. This will help estimates and predictions of wildfire emissions.
Pablo E. Saide, Meng Gao, Zifeng Lu, Daniel L. Goldberg, David G. Streets, Jung-Hun Woo, Andreas Beyersdorf, Chelsea A. Corr, Kenneth L. Thornhill, Bruce Anderson, Johnathan W. Hair, Amin R. Nehrir, Glenn S. Diskin, Jose L. Jimenez, Benjamin A. Nault, Pedro Campuzano-Jost, Jack Dibb, Eric Heim, Kara D. Lamb, Joshua P. Schwarz, Anne E. Perring, Jhoon Kim, Myungje Choi, Brent Holben, Gabriele Pfister, Alma Hodzic, Gregory R. Carmichael, Louisa Emmons, and James H. Crawford
Atmos. Chem. Phys., 20, 6455–6478,Short summary
Air quality forecasts over the Korean Peninsula captured aerosol optical depth but largely overpredicted surface PM during a Chinese haze transport event. Model deficiency was related to the calculation of optical properties. In order to improve it, aerosol size representation needs to be refined in the calculations, and the representation of aerosol properties, such as size distribution, chemical composition, refractive index, hygroscopicity parameter, and density, needs to be improved.
Alma Hodzic, Pedro Campuzano-Jost, Huisheng Bian, Mian Chin, Peter R. Colarco, Douglas A. Day, Karl D. Froyd, Bernd Heinold, Duseong S. Jo, Joseph M. Katich, John K. Kodros, Benjamin A. Nault, Jeffrey R. Pierce, Eric Ray, Jacob Schacht, Gregory P. Schill, Jason C. Schroder, Joshua P. Schwarz, Donna T. Sueper, Ina Tegen, Simone Tilmes, Kostas Tsigaridis, Pengfei Yu, and Jose L. Jimenez
Atmos. Chem. Phys., 20, 4607–4635,Short summary
Organic aerosol (OA) is a key source of uncertainty in aerosol climate effects. We present the first pole-to-pole OA characterization during the NASA Atmospheric Tomography aircraft mission. OA has a strong seasonal and zonal variability, with the highest levels in summer and over fire-influenced regions and the lowest ones in the southern high latitudes. We show that global models predict the OA distribution well but not the relative contribution of OA emissions vs. chemical production.
Md. Robiul Islam, Thilina Jayarathne, Isobel J. Simpson, Benjamin Werden, John Maben, Ashley Gilbert, Puppala S. Praveen, Sagar Adhikari, Arnico K. Panday, Maheswar Rupakheti, Donald R. Blake, Robert J. Yokelson, Peter F. DeCarlo, William C. Keene, and Elizabeth A. Stone
Atmos. Chem. Phys., 20, 2927–2951,Short summary
The Kathmandu Valley experiences high levels of air pollution. In this study, atmospheric gases and particulate matter were characterized by online and off-line measurements, with an emphasis on understanding their sources. The major sources of particulate matter and trace gases were identified as garbage burning, biomass burning, and vehicles. The majority of secondary organic aerosol was attributed to anthropogenic precursors, while a minority was attributed to biogenic gases.
Therese S. Carter, Colette L. Heald, Jose L. Jimenez, Pedro Campuzano-Jost, Yutaka Kondo, Nobuhiro Moteki, Joshua P. Schwarz, Christine Wiedinmyer, Anton S. Darmenov, Arlindo M. da Silva, and Johannes W. Kaiser
Atmos. Chem. Phys., 20, 2073–2097,Short summary
Fires and the smoke they emit impact air quality, health, and climate, but the abundance and properties of smoke remain uncertain and poorly constrained. To explore this, we compare model simulations driven by four commonly-used fire emission inventories with surface, aloft, and satellite observations. We show that across inventories smoke emissions differ by factors of 4 to 7 over North America, challenging our ability to accurately characterize the impact of smoke on air quality and climate.
Benjamin W. Clouser, Kara D. Lamb, Laszlo C. Sarkozy, Jan Habig, Volker Ebert, Harald Saathoff, Ottmar Möhler, and Elisabeth J. Moyer
Atmos. Chem. Phys., 20, 1089–1103,Short summary
Previous measurements of water vapor in the upper troposphere and lower stratosphere (UT/LS) have shown unexpectedly high concentrations of water vapor in ice clouds, which may be due to an incomplete understanding of the structure of ice and the behavior of ice growth in this part of the atmosphere. Water vapor measurements during the 2013 IsoCloud campaign at the AIDA cloud chamber show no evidence of this
anomalous supersaturationin conditions similar to the real atmosphere.
Lauren T. Fleming, Peng Lin, James M. Roberts, Vanessa Selimovic, Robert Yokelson, Julia Laskin, Alexander Laskin, and Sergey A. Nizkorodov
Atmos. Chem. Phys., 20, 1105–1129,Short summary
We have explored the nature and stability of molecules that give biomass burning smoke its faint brown color. Different types of biomass fuels were burned and the resulting smoke was collected for a detailed chemical analysis. We found that brown molecules in smoke become less colored when they are irradiated by sunlight, but this photobleaching process is very slow. This means that biomass burning smoke will remain brown-colored for a long time and efficiently warm up the atmosphere.
Alexander Moravek, Jennifer G. Murphy, Amy Hrdina, John C. Lin, Christopher Pennell, Alessandro Franchin, Ann M. Middlebrook, Dorothy L. Fibiger, Caroline C. Womack, Erin E. McDuffie, Randal Martin, Kori Moore, Munkhbayar Baasandorj, and Steven S. Brown
Atmos. Chem. Phys., 19, 15691–15709,Short summary
Ammonium nitrate is a major component of fine particulate matter of wintertime air pollution in the Great Salt Lake Region (UT, USA). We investigate the sources of ammonia in the region by using aircraft observations and comparing them to modelled ammonia mixing ratios based on emission inventory estimates. The results suggest that ammonia emissions are underestimated, specifically in regions with high agricultural activity, while ammonia in Salt Lake City is mainly of local origin.
Matthew M. Coggon, Christopher Y. Lim, Abigail R. Koss, Kanako Sekimoto, Bin Yuan, Jessica B. Gilman, David H. Hagan, Vanessa Selimovic, Kyle J. Zarzana, Steven S. Brown, James M. Roberts, Markus Müller, Robert Yokelson, Armin Wisthaler, Jordan E. Krechmer, Jose L. Jimenez, Christopher Cappa, Jesse H. Kroll, Joost de Gouw, and Carsten Warneke
Atmos. Chem. Phys., 19, 14875–14899,Short summary
Wildfire emissions significantly contribute to adverse air quality; however, the chemical processes that lead to hazardous pollutants, such as ozone, are not fully understood. In this study, we describe laboratory experiments where we simulate the atmospheric chemistry of smoke emitted from a range of biomass fuels. We show that certain understudied compounds, such as furans and phenolic compounds, are significant contributors to pollutants formed as a result of typical atmospheric oxidation.
Jiajue Chai, David J. Miller, Eric Scheuer, Jack Dibb, Vanessa Selimovic, Robert Yokelson, Kyle J. Zarzana, Steven S. Brown, Abigail R. Koss, Carsten Warneke, and Meredith Hastings
Atmos. Meas. Tech., 12, 6303–6317,Short summary
Isotopic analysis offers a potential tool to distinguish between sources and interpret transformation pathways of atmospheric species. We applied recently developed techniques in our lab to characterize the isotopic composition of reactive nitrogen species (NOx, HONO, HNO3, pNO3-) in fresh biomass burning emissions. Intercomparison with other techniques confirms the suitability of our methods, allowing for future applications of our techniques in a variety of environments.
Karl D. Froyd, Daniel M. Murphy, Charles A. Brock, Pedro Campuzano-Jost, Jack E. Dibb, Jose-Luis Jimenez, Agnieszka Kupc, Ann M. Middlebrook, Gregory P. Schill, Kenneth L. Thornhill, Christina J. Williamson, James C. Wilson, and Luke D. Ziemba
Atmos. Meas. Tech., 12, 6209–6239,Short summary
Single-particle mass spectrometer (SPMS) instruments characterize the composition of individual aerosol particles in real time. We present a new method that combines SPMS composition with independently measured particle size distributions to determine absolute number, surface area, volume, and mass concentrations of mineral dust, biomass burning, sea salt, and other climate-relevant atmospheric particle types, with a fast time response applicable to aircraft sampling.
Maria A. Zawadowicz, Karl D. Froyd, Anne E. Perring, Daniel M. Murphy, Dominick V. Spracklen, Colette L. Heald, Peter R. Buseck, and Daniel J. Cziczo
Atmos. Chem. Phys., 19, 13859–13870,Short summary
We report measurements of small particles of biological origin (for example, fragments of bacteria, pollen, or fungal spores) in the atmosphere over the continental United States. We use a recently developed identification technique based on airborne mass spectrometry in conjunction with an extensive aircraft dataset. We show that biological particles are present at altitudes up to 10 km and we quantify typical concentrations.
Huisheng Bian, Karl Froyd, Daniel M. Murphy, Jack Dibb, Anton Darmenov, Mian Chin, Peter R. Colarco, Arlindo da Silva, Tom L. Kucsera, Gregory Schill, Hongbin Yu, Paul Bui, Maximilian Dollner, Bernadett Weinzierl, and Alexander Smirnov
Atmos. Chem. Phys., 19, 10773–10785,Short summary
We address the GEOS-GOCART sea salt simulations constrained by NASA EVS ATom measurements, as well as those by MODIS and the AERONET MAN. The study covers remote regions over the Pacific, Atlantic, and Southern oceans from near the surface to ~ 12 km altitude and covers both summer and winter seasons. Important sea salt fields, e.g., mass mixing ratio, vertical distribution, size distribution, and marine aerosol AOD, as well as their relationship to relative humidity and emissions, are examined.
Erin E. McDuffie, Caroline C. Womack, Dorothy L. Fibiger, William P. Dube, Alessandro Franchin, Ann M. Middlebrook, Lexie Goldberger, Ben H. Lee, Joel A. Thornton, Alexander Moravek, Jennifer G. Murphy, Munkhbayar Baasandorj, and Steven S. Brown
Atmos. Chem. Phys., 19, 9287–9308,Short summary
Populated mountain basins, including the Salt Lake Valley (SLV) in Utah, suffer from wintertime stagnation events that trap emissions near the surface and cause fine particulate matter (PM2.5) concentrations to reach unhealthy levels. Previously limited by a lack of nighttime measurements, this study uses 2017 UWFPS aircraft campaign data, in combination with a box model, to show that nitrogen chemistry above the surface at night is a major source of PM2.5 during a wintertime event in the SLV.
Xin Chen, Dylan B. Millet, Hanwant B. Singh, Armin Wisthaler, Eric C. Apel, Elliot L. Atlas, Donald R. Blake, Ilann Bourgeois, Steven S. Brown, John D. Crounse, Joost A. de Gouw, Frank M. Flocke, Alan Fried, Brian G. Heikes, Rebecca S. Hornbrook, Tomas Mikoviny, Kyung-Eun Min, Markus Müller, J. Andrew Neuman, Daniel W. O'Sullivan, Jeff Peischl, Gabriele G. Pfister, Dirk Richter, James M. Roberts, Thomas B. Ryerson, Stephen R. Shertz, Chelsea R. Thompson, Victoria Treadaway, Patrick R. Veres, James Walega, Carsten Warneke, Rebecca A. Washenfelder, Petter Weibring, and Bin Yuan
Atmos. Chem. Phys., 19, 9097–9123,Short summary
Volatile organic compounds (VOCs) affect air quality and modify the lifetimes of other pollutants. We combine a high-resolution 3-D atmospheric model with an ensemble of aircraft observations to perform an integrated analysis of the VOC budget over North America. We find that biogenic emissions provide the main source of VOC reactivity even in most major cities. Our findings point to key gaps in current models related to oxygenated VOCs and to the distribution of VOCs in the free troposphere.
Kara D. Lamb
Atmos. Meas. Tech., 12, 3885–3906,Short summary
Recent atmospheric observations have indicated emissions of iron-oxide-containing aerosols from anthropogenic sources could be 8x higher than previous estimates, leading models to underestimate their climate impact. Previous studies have shown the single particle soot photometer (SP2) can quantify the atmospheric abundance of these aerosols. Here, I explore a machine learning approach to improve SP2 detection, significantly reducing misclassifications of other aerosols as iron oxide aerosols.
Min Zhong, Eri Saikawa, Alexander Avramov, Chen Chen, Boya Sun, Wenlu Ye, William C. Keene, Robert J. Yokelson, Thilina Jayarathne, Elizabeth A. Stone, Maheswar Rupakheti, and Arnico K. Panday
Atmos. Chem. Phys., 19, 8209–8228,Short summary
Air pollution is one of the most pressing environmental issues in the Kathmandu Valley, the capital city of Nepal. We estimated emissions from two of the major source types in the valley (vehicles and brick kilns) and found that they have significant impacts on air quality surrounding the valley. Our results highlight the importance of improving local emissions estimates for air quality modeling.
Charles A. Brock, Christina Williamson, Agnieszka Kupc, Karl D. Froyd, Frank Erdesz, Nicholas Wagner, Matthews Richardson, Joshua P. Schwarz, Ru-Shan Gao, Joseph M. Katich, Pedro Campuzano-Jost, Benjamin A. Nault, Jason C. Schroder, Jose L. Jimenez, Bernadett Weinzierl, Maximilian Dollner, ThaoPaul Bui, and Daniel M. Murphy
Atmos. Meas. Tech., 12, 3081–3099,Short summary
From 2016 to 2018 a NASA aircraft profiled the atmosphere from 180 m to ~12 km from the Arctic to the Antarctic over both the Pacific and Atlantic oceans. This program, ATom, sought to sample atmospheric chemical composition to compare with global climate models. We describe the how measurements of particulate matter were made during ATom, and show that the instrument performance was excellent. Data from this project can be used with confidence to evaluate models and compare with satellites.
Daniel M. Murphy, Karl D. Froyd, Huisheng Bian, Charles A. Brock, Jack E. Dibb, Joshua P. DiGangi, Glenn Diskin, Maximillian Dollner, Agnieszka Kupc, Eric M. Scheuer, Gregory P. Schill, Bernadett Weinzierl, Christina J. Williamson, and Pengfei Yu
Atmos. Chem. Phys., 19, 4093–4104,Short summary
We present the first data on the concentration of sea-salt aerosol throughout most of the depth of the troposphere and a wide range of latitudes. Sea-salt concentrations in the upper troposphere are very small. This puts stringent limits on how sea-salt aerosol affects halogen and nitric acid chemistry there. With a widely distributed source, sea-salt aerosol provides an excellent test of wet scavenging and vertical transport of aerosols in chemical transport models.
Vanessa Selimovic, Robert J. Yokelson, Gavin R. McMeeking, and Sarah Coefield
Atmos. Chem. Phys., 19, 3905–3926,Short summary
A massive wildfire smoke episode impacted the western US and Canada in summer 2017. We measured CO, other trace gases, PM, BC, and aerosol optical properties at a heavily impacted, ground-based site affected by this event. Brown carbon diminished as smoke aged but was a persistent component of the regional smoke, accounting for about half of aerosol absorption at 401 nm on average. The PM / CO ratios suggested aerosol evaporation was dominant at the surface at smoke ages of up to ~ 1–2 days.
Nick Jordan, Connie Z. Ye, Satyaki Ghosh, Rebecca A. Washenfelder, Steven S. Brown, and Hans D. Osthoff
Atmos. Meas. Tech., 12, 1277–1293,Short summary
A new spectrometer to measure abundances of the atmospheric trace gases nitrogen dioxide and iodine is described. The spectrometer uses a light-emitting diode between 470 and 540 nm and two highly reflective mirrors to yield an effective absorption path of 6.3 km. We remeasured scattering cross sections of common atmospheric gases in the cyan region and present sample NO2 measurements that agreed with those made with a laser-based instrument.
J. Christopher Kaiser, Johannes Hendricks, Mattia Righi, Patrick Jöckel, Holger Tost, Konrad Kandler, Bernadett Weinzierl, Daniel Sauer, Katharina Heimerl, Joshua P. Schwarz, Anne E. Perring, and Thomas Popp
Geosci. Model Dev., 12, 541–579,Short summary
The implementation of the aerosol microphysics submodel MADE3 into the global atmospheric chemistry model EMAC is described and evaluated against an extensive pool of observational data, focusing on aerosol mass and number concentrations, size distributions, composition, and optical properties. EMAC (MADE3) is able to reproduce main aerosol properties reasonably well, in line with the performance of other global aerosol models.
Coty N. Jen, Lindsay E. Hatch, Vanessa Selimovic, Robert J. Yokelson, Robert Weber, Arantza E. Fernandez, Nathan M. Kreisberg, Kelley C. Barsanti, and Allen H. Goldstein
Atmos. Chem. Phys., 19, 1013–1026,Short summary
Wildfires in the western US are occurring more frequently and burning larger land areas. Smoke from these fires will play a greater role in regional air quality and atmospheric chemistry than in the past. To help fire and climate modelers and atmospheric experimentalists better understand how smoke impacts the environment, we have separated, identified, classified, and quantified the thousands of organic compounds found in smoke and related their amounts emitted to fire conditions.
Benjamin A. Nault, Pedro Campuzano-Jost, Douglas A. Day, Jason C. Schroder, Bruce Anderson, Andreas J. Beyersdorf, Donald R. Blake, William H. Brune, Yonghoon Choi, Chelsea A. Corr, Joost A. de Gouw, Jack Dibb, Joshua P. DiGangi, Glenn S. Diskin, Alan Fried, L. Gregory Huey, Michelle J. Kim, Christoph J. Knote, Kara D. Lamb, Taehyoung Lee, Taehyun Park, Sally E. Pusede, Eric Scheuer, Kenneth L. Thornhill, Jung-Hun Woo, and Jose L. Jimenez
Atmos. Chem. Phys., 18, 17769–17800,Short summary
Aerosol impacts visibility and human health in large cities. Sources of aerosols are still highly uncertain, especially for cities surrounded by numerous other cities. We use observations collected during the Korea–United States Air Quality study to determine sources of organic aerosol (OA). We find that secondary OA (SOA) is rapidly produced over Seoul, South Korea, and that the sources of the SOA originate from short-lived hydrocarbons, which originate from local emissions.
Alessandro Franchin, Dorothy L. Fibiger, Lexie Goldberger, Erin E. McDuffie, Alexander Moravek, Caroline C. Womack, Erik T. Crosman, Kenneth S. Docherty, William P. Dube, Sebastian W. Hoch, Ben H. Lee, Russell Long, Jennifer G. Murphy, Joel A. Thornton, Steven S. Brown, Munkhbayar Baasandorj, and Ann M. Middlebrook
Atmos. Chem. Phys., 18, 17259–17276,Short summary
We present the results of aerosol and trace gas measurements from airborne and ground-based platforms. The measurements took place in January–February 2017 in northern Utah as part of the Utah Winter Fine Particulate Study (UWFPS). We characterized the chemical composition of PM1 on a regional scale, also probing the vertical dimension. We used a thermodynamic model to study the effectiveness of limiting total ammonium or total nitrate as a strategy to control aerosol concentrations.
Kyle J. Zarzana, Vanessa Selimovic, Abigail R. Koss, Kanako Sekimoto, Matthew M. Coggon, Bin Yuan, William P. Dubé, Robert J. Yokelson, Carsten Warneke, Joost A. de Gouw, James M. Roberts, and Steven S. Brown
Atmos. Chem. Phys., 18, 15451–15470,Short summary
Emissions of glyoxal and methylglyoxal from fuels common to the western United States were measured using cavity-enhanced spectroscopy, which provides a more selective measurement of those compounds than was previously available. Primary emissions of glyoxal were lower than previously reported and showed variability between the different fuel groups. However, emissions of glyoxal relative to formaldehyde were constant across almost all the fuel groups at 6 %–7 %.
J. Douglas Goetz, Michael R. Giordano, Chelsea E. Stockwell, Ted J. Christian, Rashmi Maharjan, Sagar Adhikari, Prakash V. Bhave, Puppala S. Praveen, Arnico K. Panday, Thilina Jayarathne, Elizabeth A. Stone, Robert J. Yokelson, and Peter F. DeCarlo
Atmos. Chem. Phys., 18, 14653–14679,Short summary
Size distributions and emission factors of submicron aerosol were quantified using online techniques for a variety of common but under-sampled combustion sources in South Asia: wood and dung cooking fires, groundwater pumps, brick kilns, trash burning, and open burning of crop residues. Optical properties (brown carbon light absorption and the absorption Ångström exponent, AAE) of the emissions were also investigated. Contextual comparisons to the literature and other NAMaSTE results were made.
Daniela Wimmer, Stephany Buenrostro Mazon, Hanna Elina Manninen, Juha Kangasluoma, Alessandro Franchin, Tuomo Nieminen, John Backman, Jian Wang, Chongai Kuang, Radovan Krejci, Joel Brito, Fernando Goncalves Morais, Scot Turnbull Martin, Paulo Artaxo, Markku Kulmala, Veli-Matti Kerminen, and Tuukka Petäjä
Atmos. Chem. Phys., 18, 13245–13264,Short summary
This work focuses on understanding the production of very small airborne particles in the undisturbed environment of the Amazon basin. Computer models have shown that up to 70 % of these tiny particles are responsible for cloud formation on a global scale. The processes behind the production of these very small particles have been studied intensely recently. Their appearance has been observed almost all over the world. We directly measure sub-3 nm aerosols for the first time in the Amazon basin.
Kanako Sekimoto, Abigail R. Koss, Jessica B. Gilman, Vanessa Selimovic, Matthew M. Coggon, Kyle J. Zarzana, Bin Yuan, Brian M. Lerner, Steven S. Brown, Carsten Warneke, Robert J. Yokelson, James M. Roberts, and Joost de Gouw
Atmos. Chem. Phys., 18, 9263–9281,Short summary
We found that on average 85 % of the VOC emissions from biomass burning across various fuels representative of the western US (including various coniferous and chaparral fuels) can be explained using only two emission profiles: (i) a high-temperature pyrolysis profile and (ii) a low-temperature pyrolysis profile. The high-temperature profile is quantitatively similar between different fuel types (r2 > 0.84), and likewise for the low-temperature profile.
Christina Williamson, Agnieszka Kupc, James Wilson, David W. Gesler, J. Michael Reeves, Frank Erdesz, Richard McLaughlin, and Charles A. Brock
Atmos. Meas. Tech., 11, 3491–3509,Short summary
We describe the operating principle, design and performance of the Nucleation Mode Aerosol Size Spectrometer (NMASS), an instrument composed of 5 condensation particle counters measuring size selected particle concentrations between 3 and 60 nm. An inversion to recover size distributions from the data is evaluated. Calibrations of a 2-NMASS system for measuring size distributions on the NASA Atmospheric Tomography Mission, and examples of its in-flight performance are presented.
Chelsea E. Stockwell, Agnieszka Kupc, Bartłomiej Witkowski, Ranajit K. Talukdar, Yong Liu, Vanessa Selimovic, Kyle J. Zarzana, Kanako Sekimoto, Carsten Warneke, Rebecca A. Washenfelder, Robert J. Yokelson, Ann M. Middlebrook, and James M. Roberts
Atmos. Meas. Tech., 11, 2749–2768,Short summary
This work investigates the total conversion of particle-bound nitrogen and organic carbon across platinum and molybdenum catalysts followed by NO–O3 chemiluminescence and nondispersive infrared CO2 detection. We show the instrument is an accurate particle mass measurement method and demonstrate its ability to calibrate particle mass measurement instrumentation through comparisons with a calibrated particle-into-liquid sampler coupled to an electrospray ionization source of a mass spectrometer.
Abigail R. Koss, Kanako Sekimoto, Jessica B. Gilman, Vanessa Selimovic, Matthew M. Coggon, Kyle J. Zarzana, Bin Yuan, Brian M. Lerner, Steven S. Brown, Jose L. Jimenez, Jordan Krechmer, James M. Roberts, Carsten Warneke, Robert J. Yokelson, and Joost de Gouw
Atmos. Chem. Phys., 18, 3299–3319,Short summary
Non-methane organic gases (NMOGs) were detected by proton-transfer-reaction mass spectrometry (PTR-ToF) during an extensive laboratory characterization of wildfire emissions. Identifications for PTR-ToF ion masses are proposed and supported by a combination of techniques. Overall excellent agreement with other instrumentation is shown. Scalable emission factors and ratios are reported for many newly reported reactive species. An analysis of chemical characteristics is presented.
Vanessa Selimovic, Robert J. Yokelson, Carsten Warneke, James M. Roberts, Joost de Gouw, James Reardon, and David W. T. Griffith
Atmos. Chem. Phys., 18, 2929–2948,Short summary
We burned fuels representing western US wildfires in large-scale laboratory simulations to generate relevant emissions as confirmed by lab–field comparison. We report emission factors (EFs) for light scattering and absorption and BC along with SSA at 870 and 401 nm and AAE. We report EF for 22 trace gases that are major inorganic and organic emissions from flaming and smoldering. We report trace gas EF for species rarely (NH3) or not yet measured (e.g., HONO, acetic acid) for real US wildfires.
Thilina Jayarathne, Chelsea E. Stockwell, Ashley A. Gilbert, Kaitlyn Daugherty, Mark A. Cochrane, Kevin C. Ryan, Erianto I. Putra, Bambang H. Saharjo, Ati D. Nurhayati, Israr Albar, Robert J. Yokelson, and Elizabeth A. Stone
Atmos. Chem. Phys., 18, 2585–2600,Short summary
Fine particulate matter (PM2.5) emissions from Indonesian peat burning were measured in situ. Fuel-based emission factors from 6.0–29.6 gPM kg-1. Detailed chemical analysis revealed high levels of organic carbon that was primarily water insoluble, little to no detectable elemental carbon, and alkane contributions to organic carbon in the range of 6 %. These data were used to estimate that 3.2–11 Tg of PM2.5 were emitted by the 2015 peat burning episodes in Indonesia.
Thilina Jayarathne, Chelsea E. Stockwell, Prakash V. Bhave, Puppala S. Praveen, Chathurika M. Rathnayake, Md. Robiul Islam, Arnico K. Panday, Sagar Adhikari, Rashmi Maharjan, J. Douglas Goetz, Peter F. DeCarlo, Eri Saikawa, Robert J. Yokelson, and Elizabeth A. Stone
Atmos. Chem. Phys., 18, 2259–2286,Short summary
Emissions of fine particulate matter and its constituents were quantified for a variety of under-sampled combustion sources in South Asia: wood and dung cooking fires, generators, groundwater pumps, brick kilns, trash burning, and open burning of biomasses. Garbage burning and three-stone cooking fires were among the highest emitters, while servicing of motor vehicles significantly reduced PM. These data may be used in source apportionment and to update regional and global emission inventories.
Xuan Wang, Colette L. Heald, Jiumeng Liu, Rodney J. Weber, Pedro Campuzano-Jost, Jose L. Jimenez, Joshua P. Schwarz, and Anne E. Perring
Atmos. Chem. Phys., 18, 635–653,Short summary
Brown carbon (BrC) contributes significantly to uncertainty in estimating the global direct radiative effect (DRE) of aerosols. We develop a global model simulation of BrC and test it against BrC absorption measurements from two aircraft campaigns in the continental United States. We suggest that BrC DRE has been overestimated previously due to the lack of observational constraints from direct measurements and omission of the effects of photochemical whitening.
Agnieszka Kupc, Christina Williamson, Nicholas L. Wagner, Mathews Richardson, and Charles A. Brock
Atmos. Meas. Tech., 11, 369–383,
Jin Liao, Charles A. Brock, Daniel M. Murphy, Donna T. Sueper, André Welti, and Ann M. Middlebrook
Atmos. Meas. Tech., 10, 3801–3820,Short summary
The Aerodyne aerosol mass spectrometer (AMS) has emerged as a widely used method for measuring the real-time, submicron, nonrefractory aerosol composition. A large uncertainty in accurate measurements with the AMS (the collection efficiency due to particle bounce) is evaluated in this paper using in situ measurements of particle light scattering. Current calculations of the collection efficiency reasonably predict this effect in acidic environments, resulting in more confidence for AMS results.
Linda M. J. Kooijmans, Kadmiel Maseyk, Ulli Seibt, Wu Sun, Timo Vesala, Ivan Mammarella, Pasi Kolari, Juho Aalto, Alessandro Franchin, Roberta Vecchi, Gianluigi Valli, and Huilin Chen
Atmos. Chem. Phys., 17, 11453–11465,Short summary
Carbon cycle studies rely on the accuracy of models to estimate the amount of CO2 being taken up by vegetation. The gas carbonyl sulfide (COS) can serve as a tool to estimate the vegetative CO2 uptake by scaling the ecosystem uptake of COS to that of CO2. Here we investigate the nighttime fluxes of COS. The relationships found in this study will aid in implementing nighttime COS uptake in models, which is key to obtain accurate estimates of vegetative CO2 uptake with the use of COS.
Guido R. van der Werf, James T. Randerson, Louis Giglio, Thijs T. van Leeuwen, Yang Chen, Brendan M. Rogers, Mingquan Mu, Margreet J. E. van Marle, Douglas C. Morton, G. James Collatz, Robert J. Yokelson, and Prasad S. Kasibhatla
Earth Syst. Sci. Data, 9, 697–720,Short summary
Fires occur in many vegetation types and are sometimes natural but often ignited by humans for various purposes. We have estimated how much area they burn globally and what their emissions are. Total burned area is roughly equivalent to the size of the EU with most fires burning in tropical savannas. Their emissions vary substantially from year to year and contribute to the atmospheric burdens of many trace gases and aerosols. The 20-year dataset is mostly suited for large-scale assessments.
Georgios Tsagkogeorgas, Pontus Roldin, Jonathan Duplissy, Linda Rondo, Jasmin Tröstl, Jay G. Slowik, Sebastian Ehrhart, Alessandro Franchin, Andreas Kürten, Antonio Amorim, Federico Bianchi, Jasper Kirkby, Tuukka Petäjä, Urs Baltensperger, Michael Boy, Joachim Curtius, Richard C. Flagan, Markku Kulmala, Neil M. Donahue, and Frank Stratmann
Atmos. Chem. Phys., 17, 8923–8938,Short summary
The H2SO4 vapour pressure plays key role in Earth's and Venus' atmospheres. In regions where RH is low and stabilising bases are scarce, H2SO4 can evaporate from particles; however the H2SO4 vapour pressure at low RH is uncertain. To address this, we measured H2SO4 evaporation versus T and RH in the CLOUD chamber and constrained the equilibrium constants for dissociation and dehydration of H2SO4. This study is important for nucleation, particle growth and H2SO4 formation occurring in atmosphere.
Christopher Chan Miller, Daniel J. Jacob, Eloise A. Marais, Karen Yu, Katherine R. Travis, Patrick S. Kim, Jenny A. Fisher, Lei Zhu, Glenn M. Wolfe, Thomas F. Hanisco, Frank N. Keutsch, Jennifer Kaiser, Kyung-Eun Min, Steven S. Brown, Rebecca A. Washenfelder, Gonzalo González Abad, and Kelly Chance
Atmos. Chem. Phys., 17, 8725–8738,Short summary
The use of satellite glyoxal observations for estimating isoprene emissions has been limited by knowledge of the glyoxal yield from isoprene. We use SENEX aircraft observations over the southeast US to evaluate glyoxal yields from isoprene in a 3-D atmospheric model. The SENEX observations support a pathway for glyoxal formation in pristine regions that we propose here, which may have implications for improving isoprene emissions estimates from upcoming high-resolution geostationary satellites.
Maria A. Zawadowicz, Karl D. Froyd, Daniel M. Murphy, and Daniel J. Cziczo
Atmos. Chem. Phys., 17, 7193–7212,Short summary
This paper reports the results of laboratory and field measurements of primary biological aerosol particles using single-particle mass spectrometry (SPMS). Identification of biological particles using SPMS can be challenging, as their mass spectra can present features similar to phosphorus-containing minerals and combustion by-products. Using a large database of laboratory measurements, a criterion for the identification of biological particles has been developed.
Caroline C. Womack, J. Andrew Neuman, Patrick R. Veres, Scott J. Eilerman, Charles A. Brock, Zachary C. J. Decker, Kyle J. Zarzana, William P. Dube, Robert J. Wild, Paul J. Wooldridge, Ronald C. Cohen, and Steven S. Brown
Atmos. Meas. Tech., 10, 1911–1926,Short summary
The accurate detection of reactive nitrogen species (NOy) is key to understanding tropospheric ozone production. Typically, NOy is detected by thermal conversion to NO2, followed by NO2 detection. Here, we assess the conversion efficiency of several NOy species to NO2 in a thermal dissociation cavity ring-down spectrometer and discuss how this conversion efficiency is affected by certain experimental conditions, such as oven residence time, and interferences from non-NOy species.
Ellis Shipley Robinson, Ru-Shan Gao, Joshua P. Schwarz, David W. Fahey, and Anne E. Perring
Atmos. Meas. Tech., 10, 1755–1768,
Brett B. Palm, Pedro Campuzano-Jost, Douglas A. Day, Amber M. Ortega, Juliane L. Fry, Steven S. Brown, Kyle J. Zarzana, William Dube, Nicholas L. Wagner, Danielle C. Draper, Lisa Kaser, Werner Jud, Thomas Karl, Armin Hansel, Cándido Gutiérrez-Montes, and Jose L. Jimenez
Atmos. Chem. Phys., 17, 5331–5354,Short summary
Ambient forest air was oxidized by OH, O3, or NO3 inside an oxidation flow reactor, leading to formation of particulate matter from any gaseous precursors found in the air. Closure was achieved between the amount of particulate mass formed from O3 and NO3 oxidation and the amount predicted from speciated gaseous precursors, which was in contrast to previous results for OH oxidation (Palm et al., 2016). Elemental analysis of the particulate mass formed in the reactor is presented.
Rudra P. Pokhrel, Eric R. Beamesderfer, Nick L. Wagner, Justin M. Langridge, Daniel A. Lack, Thilina Jayarathne, Elizabeth A. Stone, Chelsea E. Stockwell, Robert J. Yokelson, and Shane M. Murphy
Atmos. Chem. Phys., 17, 5063–5078,Short summary
This study investigates enhancement of black carbon (BC) absorption in biomass burning emissions due to absorbing and non-absorbing coatings. The fraction of absorption due to BC, brown carbon (BrC), and lensing is estimated using different approaches. The similarities and differences between the results from these approaches are discussed. Absorption by BrC is shown to have good correlation with the elemental to organic carbon ratio (EC / OC) and AAE.
Lindsay E. Hatch, Robert J. Yokelson, Chelsea E. Stockwell, Patrick R. Veres, Isobel J. Simpson, Donald R. Blake, John J. Orlando, and Kelley C. Barsanti
Atmos. Chem. Phys., 17, 1471–1489,Short summary
The most comprehensive database of gaseous biomass burning emissions to date was compiled. Four complementary instruments were deployed together during laboratory fires. The results generally compared within experimental uncertainty and highlighted that a range of measurement approaches are required for adequate characterization of smoke composition. Observed compounds were binned based on volatility, and priority recommendations were made to improve secondary organic aerosol predictions.
Jiumeng Liu, Peng Lin, Alexander Laskin, Julia Laskin, Shawn M. Kathmann, Matthew Wise, Ryan Caylor, Felisha Imholt, Vanessa Selimovic, and John E. Shilling
Atmos. Chem. Phys., 16, 12815–12827,Short summary
Light absorbing organic aerosols (BrC) absorb sunlight thereby influencing climate; however, understanding of the link between their optical properties and environmental variables remains limited. Our chamber experiment results suggest that variables including NOx concentration, RH level, and photolysis time have considerable influence on secondary BrC optical properties. The results contribute to a more accurate characterization of the impacts of aerosols on climate, especially in urban areas.
Chelsea E. Stockwell, Thilina Jayarathne, Mark A. Cochrane, Kevin C. Ryan, Erianto I. Putra, Bambang H. Saharjo, Ati D. Nurhayati, Israr Albar, Donald R. Blake, Isobel J. Simpson, Elizabeth A. Stone, and Robert J. Yokelson
Atmos. Chem. Phys., 16, 11711–11732,Short summary
We present the first or rare field measurements of emission factors for Indonesian peat fires made in Borneo during the 2015 El Niño. The data include up to 90 gases, aerosol mass, and aerosol optical properties at two wavelengths (405 and 870 nm). Brown carbon dominates aerosol absorption, revisions to previous values for greenhouse gas emissions are supported and air toxics are assessed.
Chelsea E. Stockwell, Ted J. Christian, J. Douglas Goetz, Thilina Jayarathne, Prakash V. Bhave, Puppala S. Praveen, Sagar Adhikari, Rashmi Maharjan, Peter F. DeCarlo, Elizabeth A. Stone, Eri Saikawa, Donald R. Blake, Isobel J. Simpson, Robert J. Yokelson, and Arnico K. Panday
Atmos. Chem. Phys., 16, 11043–11081,Short summary
We present the first, or rare, field measurements in South Asia of emission factors for up to 80 gases (pollutants, greenhouse gases, and precursors) and black carbon and aerosol optical properties at 405 and 870 nm for many previously under-sampled sources that are important in developing countries such as cooking with dung and wood, garbage and crop residue burning, brick kilns, motorcycles, generators and pumps, etc. Brown carbon contributes significantly to total aerosol absorption.
Rudra P. Pokhrel, Nick L. Wagner, Justin M. Langridge, Daniel A. Lack, Thilina Jayarathne, Elizabeth A. Stone, Chelsea E. Stockwell, Robert J. Yokelson, and Shane M. Murphy
Atmos. Chem. Phys., 16, 9549–9561,Short summary
This paper gives first multi-wavelength estimates of SSA and AAE of emissions from combustion of Indonesian peat. In addition, it demonstrates that SSA of biomass burning emissions can be parameterized with EC / (EC+OC) and that this parameterization is quantitatively superior to previously published parameterizations based on MCE. It also shows that EC / (EC+OC) parameterization accurately predicts SSA during the first few hours of aging of a biomass burning plume.
Carsten Warneke, Michael Trainer, Joost A. de Gouw, David D. Parrish, David W. Fahey, A. R. Ravishankara, Ann M. Middlebrook, Charles A. Brock, James M. Roberts, Steven S. Brown, Jonathan A. Neuman, Brian M. Lerner, Daniel Lack, Daniel Law, Gerhard Hübler, Iliana Pollack, Steven Sjostedt, Thomas B. Ryerson, Jessica B. Gilman, Jin Liao, John Holloway, Jeff Peischl, John B. Nowak, Kenneth C. Aikin, Kyung-Eun Min, Rebecca A. Washenfelder, Martin G. Graus, Mathew Richardson, Milos Z. Markovic, Nick L. Wagner, André Welti, Patrick R. Veres, Peter Edwards, Joshua P. Schwarz, Timothy Gordon, William P. Dube, Stuart A. McKeen, Jerome Brioude, Ravan Ahmadov, Aikaterini Bougiatioti, Jack J. Lin, Athanasios Nenes, Glenn M. Wolfe, Thomas F. Hanisco, Ben H. Lee, Felipe D. Lopez-Hilfiker, Joel A. Thornton, Frank N. Keutsch, Jennifer Kaiser, Jingqiu Mao, and Courtney D. Hatch
Atmos. Meas. Tech., 9, 3063–3093,Short summary
In this paper we describe the experimental approach, the science goals and early results of the NOAA SENEX campaign, which was focused on studying the interactions between biogenic and anthropogenic emissions to form secondary pollutants. During SENEX, the NOAA WP-3D aircraft conducted 20 research flights between 27 May and 10 July 2013 based out of Smyrna, TN. The SENEX flights included day- and nighttime flights in the Southeast as well as flights over areas with intense shale gas extraction.
Charles A. Brock, Nicholas L. Wagner, Bruce E. Anderson, Alexis R. Attwood, Andreas Beyersdorf, Pedro Campuzano-Jost, Annmarie G. Carlton, Douglas A. Day, Glenn S. Diskin, Timothy D. Gordon, Jose L. Jimenez, Daniel A. Lack, Jin Liao, Milos Z. Markovic, Ann M. Middlebrook, Nga L. Ng, Anne E. Perring, Matthews S. Richardson, Joshua P. Schwarz, Rebecca A. Washenfelder, Andre Welti, Lu Xu, Luke D. Ziemba, and Daniel M. Murphy
Atmos. Chem. Phys., 16, 4987–5007,Short summary
Microscopic pollution particles make the atmosphere look hazy and also cool the earth by sending sunlight back to space. When the air is moist, these particles swell with water and scatter even more sunlight. We showed that particles formed from organic material – which dominates particulate pollution in the southeastern U.S. – does not take up water very effectively, toward the low end of most previous studies. We also found a better way to mathematically describe this swelling process.
Charles A. Brock, Nicholas L. Wagner, Bruce E. Anderson, Andreas Beyersdorf, Pedro Campuzano-Jost, Douglas A. Day, Glenn S. Diskin, Timothy D. Gordon, Jose L. Jimenez, Daniel A. Lack, Jin Liao, Milos Z. Markovic, Ann M. Middlebrook, Anne E. Perring, Matthews S. Richardson, Joshua P. Schwarz, Andre Welti, Luke D. Ziemba, and Daniel M. Murphy
Atmos. Chem. Phys., 16, 5009–5019,Short summary
Two research aircraft made dozens of vertical profiles over rural areas in the southeastern US in summer 2013. These measurements show that, in addition to how much pollution was present and how moist the atmosphere was, the size of the pollutant particles affected how much sunlight was reflected back to space. These measurements will help climate modelers determine which characteristics of pollution are important to predict with accuracy.
Markus Müller, Bruce E. Anderson, Andreas J. Beyersdorf, James H. Crawford, Glenn S. Diskin, Philipp Eichler, Alan Fried, Frank N. Keutsch, Tomas Mikoviny, Kenneth L. Thornhill, James G. Walega, Andrew J. Weinheimer, Melissa Yang, Robert J. Yokelson, and Armin Wisthaler
Atmos. Chem. Phys., 16, 3813–3824,Short summary
Atmospheric emissions from small forest fires and their impact on regional air quality are still poorly characterized. We used an instrumented NASA P-3B aircraft to study emissions from a small forest understory fire in Georgia (USA) and to investigate chemical transformations in the fire plume in the 1 h downwind region. A state-of-the-art chemical model was able to accurately simulate key chemical processes in the aging plume.
Cenlin He, Qinbin Li, Kuo-Nan Liou, Ling Qi, Shu Tao, and Joshua P. Schwarz
Atmos. Chem. Phys., 16, 3077–3098,Short summary
Blarck carbon aging significantly affects its global distribution and thus climatic effects. This study develops a microphysics-based BC aging scheme in a global model, which substantially improves model simulations of BC over the remote Pacific. The microphysical scheme shows fast aging over source regions and much slower aging in remote regions. The microphysical aging significantly reduces global BC burden and lifetime, showing important implications for the estimate of BC radiative effects.
K.-E. Min, R. A. Washenfelder, W. P. Dubé, A. O. Langford, P. M. Edwards, K. J. Zarzana, J. Stutz, K. Lu, F. Rohrer, Y. Zhang, and S. S. Brown
Atmos. Meas. Tech., 9, 423–440,Short summary
We have developed a two-channel broadband cavity enhanced absorption spectrometer for field measurements of glyoxal, methylglyoxal, nitrous acid, nitrogen dioxide, and water. We have successfully deployed this instrument during two aircraft and two ground-based field campaigns. The demonstrated precision (2σ) for retrievals of CHOCHO, HONO, and NO2 are 34, 350, and 80 parts per trillion (pptv) in 5 s, with accuracy of 5.8, 9.0 and 5.0 %.
R. A. Washenfelder, A. R. Attwood, J. M. Flores, K. J. Zarzana, Y. Rudich, and S. S. Brown
Atmos. Meas. Tech., 9, 41–52,Short summary
Formaldehyde is the most abundant aldehyde in the atmosphere and plays an important role in photochemistry. Broadband cavity-enhanced absorption spectroscopy uses a high finesse cavity to obtain effective path lengths of kilometers. We use a diode-pumped plasma lamp and custom cavity mirrors to extend this technique further into the ultraviolet spectral region, and we achieve detection limits of hundreds of parts per trillion in 1 min for formaldehyde and nitrogen dioxide.
J. B. Gilman, B. M. Lerner, W. C. Kuster, P. D. Goldan, C. Warneke, P. R. Veres, J. M. Roberts, J. A. de Gouw, I. R. Burling, and R. J. Yokelson
Atmos. Chem. Phys., 15, 13915–13938,Short summary
A comprehensive suite of instruments was used to quantify the emissions of over 200 organic and inorganic gases from 56 laboratory burns of 18 different biomass fuel types common in the southeastern, southwestern, or northern United States. Emission ratios relative to carbon monoxide (CO) are used to characterize the composition of gases emitted by mass; OH reactivity; and potential secondary organic aerosol (SOA) precursors for the three different U.S. fuel regions presented here.
P. S. Kim, D. J. Jacob, J. A. Fisher, K. Travis, K. Yu, L. Zhu, R. M. Yantosca, M. P. Sulprizio, J. L. Jimenez, P. Campuzano-Jost, K. D. Froyd, J. Liao, J. W. Hair, M. A. Fenn, C. F. Butler, N. L. Wagner, T. D. Gordon, A. Welti, P. O. Wennberg, J. D. Crounse, J. M. St. Clair, A. P. Teng, D. B. Millet, J. P. Schwarz, M. Z. Markovic, and A. E. Perring
Atmos. Chem. Phys., 15, 10411–10433,
J. Liu, E. Scheuer, J. Dibb, G. S. Diskin, L. D. Ziemba, K. L. Thornhill, B. E. Anderson, A. Wisthaler, T. Mikoviny, J. J. Devi, M. Bergin, A. E. Perring, M. Z. Markovic, J. P. Schwarz, P. Campuzano-Jost, D. A. Day, J. L. Jimenez, and R. J. Weber
Atmos. Chem. Phys., 15, 7841–7858,Short summary
Brown carbon (BrC) is found throughout the US continental troposphere during a summer of extensive biomass burning and its prevalence relative to black carbon (BC) increases with altitude. A radiative transfer model based on direct measurements of aerosol scattering and absorption by BC and BrC shows BrC reduces top-of-atmosphere forcing by 20%. A method to estimate BrC radiative forcing efficiencies from surface-based measurements is provided.
J. Kaiser, G. M. Wolfe, K. E. Min, S. S. Brown, C. C. Miller, D. J. Jacob, J. A. deGouw, M. Graus, T. F. Hanisco, J. Holloway, J. Peischl, I. B. Pollack, T. B. Ryerson, C. Warneke, R. A. Washenfelder, and F. N. Keutsch
Atmos. Chem. Phys., 15, 7571–7583,
N. L. Wagner, C. A. Brock, W. M. Angevine, A. Beyersdorf, P. Campuzano-Jost, D. Day, J. A. de Gouw, G. S. Diskin, T. D. Gordon, M. G. Graus, J. S. Holloway, G. Huey, J. L. Jimenez, D. A. Lack, J. Liao, X. Liu, M. Z. Markovic, A. M. Middlebrook, T. Mikoviny, J. Peischl, A. E. Perring, M. S. Richardson, T. B. Ryerson, J. P. Schwarz, C. Warneke, A. Welti, A. Wisthaler, L. D. Ziemba, and D. M. Murphy
Atmos. Chem. Phys., 15, 7085–7102,Short summary
This paper investigates the summertime vertical profile of aerosol over the southeastern US using in situ measurements collected from aircraft. We use a vertical mixing model and measurements of CO to predict the vertical profile of aerosol that we would expect from vertical mixing alone and compare with the observed aerosol profile. We found a modest enhancement of aerosol in the cloudy transition layer during shallow cumulus convection and attribute the enhancement to local aerosol formation.
M. J. Alvarado, C. R. Lonsdale, R. J. Yokelson, S. K. Akagi, H. Coe, J. S. Craven, E. V. Fischer, G. R. McMeeking, J. H. Seinfeld, T. Soni, J. W. Taylor, D. R. Weise, and C. E. Wold
Atmos. Chem. Phys., 15, 6667–6688,Short summary
Being able to understand and simulate the chemical evolution of biomass burning smoke plumes under a wide variety of conditions is a critical part of forecasting the impact of these fires on air quality, atmospheric composition, and climate. Here we use an improved model of this chemistry to simulate the evolution of ozone and secondary organic aerosol within a young biomass burning smoke plume from the Williams prescribed burn in chaparral, which was sampled over California in November 2009.
A. A. May, T. Lee, G. R. McMeeking, S. Akagi, A. P. Sullivan, S. Urbanski, R. J. Yokelson, and S. M. Kreidenweis
Atmos. Chem. Phys., 15, 6323–6335,Short summary
Smoke plumes from some prescribed fires in the southeastern United States were sampled via aircraft to observe changes in organic aerosol (OA) with atmospheric transport. These plumes underwent rapid mixing, and, hence, substantial dilution with background air occurred. Dilution-driven evaporation appears to be the primary driver of OA transformations within the sampled plumes rather than photochemistry.
P. L. Hayes, A. G. Carlton, K. R. Baker, R. Ahmadov, R. A. Washenfelder, S. Alvarez, B. Rappenglück, J. B. Gilman, W. C. Kuster, J. A. de Gouw, P. Zotter, A. S. H. Prévôt, S. Szidat, T. E. Kleindienst, J. H. Offenberg, P. K. Ma, and J. L. Jimenez
Atmos. Chem. Phys., 15, 5773–5801,Short summary
(1) Four different parameterizations for the formation and chemical evolution of secondary organic aerosol (SOA) are evaluated using a box model representing the Los Angeles region during the CalNex campaign. (2) The SOA formed only from the oxidation of VOCs is insufficient to explain the observed SOA concentrations. (3) The amount of SOA mass formed from diesel vehicle emissions is estimated to be 16-27%. (4) Modeled SOA depends strongly on the P-S/IVOC volatility distribution.
L. E. Hatch, W. Luo, J. F. Pankow, R. J. Yokelson, C. E. Stockwell, and K. C. Barsanti
Atmos. Chem. Phys., 15, 1865–1899,Short summary
This work represents the first application of two-dimensional gas chromatography to broadly characterize the gas-phase emissions of biomass burning, including comparisons among the emissions from burns of selected conifer, grass, crop residue, and peat fuel types. In these smoke samples, over 700 compounds were detected, which are discussed in the context of potential secondary organic aerosol formation.
C. G. Schmitt, J. D. All, J. P. Schwarz, W. P. Arnott, R. J. Cole, E. Lapham, and A. Celestian
The Cryosphere, 9, 331–340,Short summary
This paper presents the results of 3 years of measurements of light absorbing particles on the glaciers in Peru. A new analysis technique has been developed and results are shown to be well correlated with black carbon mass estimates made with the Single Particle Soot Photometer (SP2) instrument, the state-of-the-art instrument for this type of measurement. Effective black carbon levels were found to be moderate on glaciers near cities and close to zero in more remote regions.
C. E. Stockwell, P. R. Veres, J. Williams, and R. J. Yokelson
Atmos. Chem. Phys., 15, 845–865,Short summary
We used a high-resolution proton-transfer-reaction time-of-flight mass spectrometer to measure emissions from peat, crop residue, cooking fires, etc. We assigned > 80% of the mass of gas-phase organic compounds and much of it was secondary organic aerosol precursors. The open cooking emissions were much larger than from advanced cookstoves. Little-studied N-containing organic compounds accounted for 0.1-8.7% of the fuel N and may influence new particle formation.
D. M. Murphy
Atmos. Chem. Phys., 14, 13013–13022,Short summary
The properties of cirrus clouds depend on the rate at which air cools as the cloud forms. Small-scale motions in the atmosphere have high rates of cooling. This usually leads to very small ice crystals. However, a few random cooling fluctuations will produce only a few ice crystals. This paper shows that these events are important even if they are rare: they lead to particles that sediment and influence a lot of air. The results show dehydration is less sensitive to details of ice nucleation.
B. H. Samset, G. Myhre, A. Herber, Y. Kondo, S.-M. Li, N. Moteki, M. Koike, N. Oshima, J. P. Schwarz, Y. Balkanski, S. E. Bauer, N. Bellouin, T. K. Berntsen, H. Bian, M. Chin, T. Diehl, R. C. Easter, S. J. Ghan, T. Iversen, A. Kirkevåg, J.-F. Lamarque, G. Lin, X. Liu, J. E. Penner, M. Schulz, Ø. Seland, R. B. Skeie, P. Stier, T. Takemura, K. Tsigaridis, and K. Zhang
Atmos. Chem. Phys., 14, 12465–12477,Short summary
Far from black carbon (BC) emission sources, present climate models are unable to reproduce flight measurements. By comparing recent models with data, we find that the atmospheric lifetime of BC may be overestimated in models. By adjusting modeled BC concentrations to measurements in remote regions - over oceans and at high altitudes - we arrive at a reduced estimate for BC radiative forcing over the industrial era.
X. Wang, C. L. Heald, D. A. Ridley, J. P. Schwarz, J. R. Spackman, A. E. Perring, H. Coe, D. Liu, and A. D. Clarke
Atmos. Chem. Phys., 14, 10989–11010,
A. P. Sullivan, A. A. May, T. Lee, G. R. McMeeking, S. M. Kreidenweis, S. K. Akagi, R. J. Yokelson, S. P. Urbanski, and J. L. Collett Jr.
Atmos. Chem. Phys., 14, 10535–10545,
C. E. Stockwell, R. J. Yokelson, S. M. Kreidenweis, A. L. Robinson, P. J. DeMott, R. C. Sullivan, J. Reardon, K. C. Ryan, D. W. T. Griffith, and L. Stevens
Atmos. Chem. Phys., 14, 9727–9754,
C. Knote, A. Hodzic, J. L. Jimenez, R. Volkamer, J. J. Orlando, S. Baidar, J. Brioude, J. Fast, D. R. Gentner, A. H. Goldstein, P. L. Hayes, W. B. Knighton, H. Oetjen, A. Setyan, H. Stark, R. Thalman, G. Tyndall, R. Washenfelder, E. Waxman, and Q. Zhang
Atmos. Chem. Phys., 14, 6213–6239,
C. J. Young, R. A. Washenfelder, P. M. Edwards, D. D. Parrish, J. B. Gilman, W. C. Kuster, L. H. Mielke, H. D. Osthoff, C. Tsai, O. Pikelnaya, J. Stutz, P. R. Veres, J. M. Roberts, S. Griffith, S. Dusanter, P. S. Stevens, J. Flynn, N. Grossberg, B. Lefer, J. S. Holloway, J. Peischl, T. B. Ryerson, E. L. Atlas, D. R. Blake, and S. S. Brown
Atmos. Chem. Phys., 14, 3427–3440,
S. K. Akagi, I. R. Burling, A. Mendoza, T. J. Johnson, M. Cameron, D. W. T. Griffith, C. Paton-Walsh, D. R. Weise, J. Reardon, and R. J. Yokelson
Atmos. Chem. Phys., 14, 199–215,
S. S. Brown, W. P. Dubé, R. Bahreini, A. M. Middlebrook, C. A. Brock, C. Warneke, J. A. de Gouw, R. A. Washenfelder, E. Atlas, J. Peischl, T. B. Ryerson, J. S. Holloway, J. P. Schwarz, R. Spackman, M. Trainer, D. D. Parrish, F. C. Fehshenfeld, and A. R. Ravishankara
Atmos. Chem. Phys., 13, 11317–11337,
R. J. Yokelson, M. O. Andreae, and S. K. Akagi
Atmos. Meas. Tech., 6, 2155–2158,
Z. Kipling, P. Stier, J. P. Schwarz, A. E. Perring, J. R. Spackman, G. W. Mann, C. E. Johnson, and P. J. Telford
Atmos. Chem. Phys., 13, 5969–5986,
R. A. Washenfelder, J. M. Flores, C. A. Brock, S. S. Brown, and Y. Rudich
Atmos. Meas. Tech., 6, 861–877,
S. K. Akagi, R. J. Yokelson, I. R. Burling, S. Meinardi, I. Simpson, D. R. Blake, G. R. McMeeking, A. Sullivan, T. Lee, S. Kreidenweis, S. Urbanski, J. Reardon, D. W. T. Griffith, T. J. Johnson, and D. R. Weise
Atmos. Chem. Phys., 13, 1141–1165,
R. J. Yokelson, I. R. Burling, J. B. Gilman, C. Warneke, C. E. Stockwell, J. de Gouw, S. K. Akagi, S. P. Urbanski, P. Veres, J. M. Roberts, W. C. Kuster, J. Reardon, D. W. T. Griffith, T. J. Johnson, S. Hosseini, J. W. Miller, D. R. Cocker III, H. Jung, and D. R. Weise
Atmos. Chem. Phys., 13, 89–116,
M. Laborde, M. Schnaiter, C. Linke, H. Saathoff, K.-H. Naumann, O. Möhler, S. Berlenz, U. Wagner, J. W. Taylor, D. Liu, M. Flynn, J. D. Allan, H. Coe, K. Heimerl, F. Dahlkötter, B. Weinzierl, A. G. Wollny, M. Zanatta, J. Cozic, P. Laj, R. Hitzenberger, J. P. Schwarz, and M. Gysel
Atmos. Meas. Tech., 5, 3077–3097,
Related subject area
Subject: Aerosols | Research Activity: Laboratory Studies | Altitude Range: Troposphere | Science Focus: Physics (physical properties and processes)Aerosol formation and growth rates from chamber experiments using Kalman smoothingPhase state of secondary organic aerosol in chamber photo-oxidation of mixed precursorsIce nucleation on surrogates of boreal forest SOA particles: effect of water content and oxidative ageViscosity and phase state of aerosol particles consisting of sucrose mixed with inorganic saltsObservations on hygroscopic growth and phase transitions of mixed 1, 2, 6-hexanetriol ∕ (NH4)2SO4 particles: investigation of the liquid–liquid phase separation (LLPS) dynamic process and mechanism and secondary LLPS during the dehumidificationBoundary layer structure characteristics under objective classification of persistent pollution weather types in the Beijing areaProperties and emission factors of cloud condensation nuclei from biomass cookstoves – observations of a strong dependency on potassium content in the fuelMeasurement report: Effects of NOx and seed aerosol on highly oxygenated organic molecules (HOMs) from cyclohexene ozonolysisInteractions of organosulfates with water vapor under sub- and supersaturated conditionsLaboratory study of the collection efficiency of submicron aerosol particles by cloud droplets – Part I: Influence of relative humidityHeterogeneous ice nucleation ability of aerosol particles generated from Arctic sea surface microlayer and surface seawater samples at cirrus temperaturesThe effect of (NH4)2SO4 on the freezing properties of non-mineral dust ice nucleating substances of atmospheric relevanceSize-resolved atmospheric ice-nucleating particles during East Asian dust eventsAqueous-phase behavior of glyoxal and methylglyoxal observed with carbon and oxygen K-edge X-ray absorption spectroscopyBrown carbon's emission factors and optical characteristics in household biomass burning: developing a novel algorithm for estimating the contribution of brown carbonEffect of mixing structure on the water uptake of mixtures of ammonium sulfate and phthalic acid particlesToward closure between predicted and observed particle viscosity over a wide range of temperatures and relative humidityThe effects of morphology, mobility size, and secondary organic aerosol (SOA) material coating on the ice nucleation activity of black carbon in the cirrus regimeThe ice-nucleating activity of Arctic sea surface microlayer samples and marine algal culturesComparing secondary organic aerosol (SOA) volatility distributions derived from isothermal SOA particle evaporation data and FIGAERO–CIMS measurementsLaboratory studies of fresh and aged biomass burning aerosol emitted from east African biomass fuels – Part 1: Optical propertiesEnhanced growth rate of atmospheric particles from sulfuric acidComposition and volatility of secondary organic aerosol (SOA) formed from oxidation of real tree emissions compared to simplified volatile organic compound (VOC) systemsEffects of SO2 on optical properties of secondary organic aerosol generated from photooxidation of toluene under different relative humidity conditionsInfluence of the dry aerosol particle size distribution and morphology on the cloud condensation nuclei activation. An experimental and theoretical investigationExperimental investigation into the volatilities of highly oxygenated organic molecules (HOMs)Detection of tar brown carbon with a single particle soot photometer (SP2)Complex refractive indices and single-scattering albedo of global dust aerosols in the shortwave spectrum and relationship to size and iron contentTechnical note: Frenkel, Halsey and Hill analysis of water on clay minerals: toward closure between cloud condensation nuclei activity and water adsorptionLiquid–liquid phase separation and viscosity within secondary organic aerosol generated from diesel fuel vaporsLaboratory study of the heterogeneous ice nucleation on black-carbon-containing aerosolSpecifying the light-absorbing properties of aerosol particles in fresh snow samples, collected at the Environmental Research Station Schneefernerhaus (UFS), ZugspitzeOptimization of process models for determining volatility distribution and viscosity of organic aerosols from isothermal particle evaporation dataInversely modeling homogeneous H2SO4 − H2O nucleation rate in exhaust-related conditionsThe importance of crystalline phases in ice nucleation by volcanic ashHeterogeneous ice nucleation properties of natural desert dust particles coated with a surrogate of secondary organic aerosolCloud condensation nuclei activity of six pollenkitts and the influence of their surface activityLinks of climate variability in Arctic sea ice, Eurasian teleconnection pattern and summer surface ozone pollution in North ChinaThe effect of hydrophobic glassy organic material on the cloud condensation nuclei activity of particles with different morphologiesTechnical note: The role of evolving surface tension in the formation of cloud dropletsPhysical properties of secondary photochemical aerosol from OH oxidation of a cyclic siloxaneCloud droplet activation of secondary organic aerosol is mainly controlled by molecular weight, not water solubilityProduction of particulate brown carbon during atmospheric aging of residential wood-burning emissionsEvaluating the performance of two surface layer schemes for the momentum and heat exchange processes during severe haze pollution in Jing-Jin-Ji in eastern ChinaMeasured particle water uptake enhanced by co-condensing vapoursCloud droplet activation of black carbon particles coated with organic compounds of varying solubilityMeasurement and modeling of the multiwavelength optical properties of uncoated flame-generated sootLiquid–liquid phase separation in organic particles containing one and two organic species: importance of the average O : CEstablishing the impact of model surfactants on cloud condensation nuclei activity of sea spray aerosol mimicsMorphological transformation of soot: investigation of microphysical processes during the condensation of sulfuric acid and limonene ozonolysis product vapors
Matthew Ozon, Dominik Stolzenburg, Lubna Dada, Aku Seppänen, and Kari E. J. Lehtinen
Atmos. Chem. Phys., 21, 12595–12611,Short summary
Measuring the rate at which aerosol particles are formed is of importance for understanding climate change. We present an analysis method based on Kalman smoothing, which retrieves new particle formation and growth rates from size-distribution measurements. We apply it to atmospheric simulation chamber experiments and show that it agrees well with traditional methods. In addition, it provides reliable uncertainty estimates, and we suggest instrument design optimisation for signal processing.
Yu Wang, Aristeidis Voliotis, Yunqi Shao, Taomou Zong, Xiangxinyue Meng, Mao Du, Dawei Hu, Ying Chen, Zhijun Wu, M. Rami Alfarra, and Gordon McFiggans
Atmos. Chem. Phys., 21, 11303–11316,Short summary
Aerosol phase behaviour plays a profound role in atmospheric physicochemical processes. We designed dedicated chamber experiments to study the phase state of secondary organic aerosol from biogenic and anthropogenic mixed precursors. Our results highlight the key role of the organic–inorganic ratio and relative humidity in phase state, but the sources and organic composition are less important. The result provides solid laboratory evidence for understanding aerosol phase in a complex atmosphere.
Ana A. Piedehierro, André Welti, Angela Buchholz, Kimmo Korhonen, Iida Pullinen, Ilkka Summanen, Annele Virtanen, and Ari Laaksonen
Atmos. Chem. Phys., 21, 11069–11078,Short summary
Ice crystals in cirrus clouds contain particles that start ice formation. We study whether particles forming above boreal forests can help in the making of cirrus clouds and if the water content in the particles affects this property. In the laboratory, we made boreal-forest-like particles and cooled and humidified them to measure whether an ice crystal develops. We found that only when dry can these particles form an ice crystal but no better than solution droplets.
Young-Chul Song, Joseph Lilek, Jae Bong Lee, Man Nin Chan, Zhijun Wu, Andreas Zuend, and Mijung Song
Atmos. Chem. Phys., 21, 10215–10228,Short summary
We report viscosity of binary mixtures of organic material / H2O and inorganic salts / H2O, as well as ternary mixtures of organic material / inorganic salts/ H2O, over the atmospheric relative humidity (RH) range. The viscosity measurements indicate that the studied mixed organic–inorganic particles range in phase state from liquid to semi-solid or even solid across the atmospheric RH range at a temperature of 293 K.
Shuaishuai Ma, Zhe Chen, Shufeng Pang, and Yunhong Zhang
Atmos. Chem. Phys., 21, 9705–9717,Short summary
LLPS, efflorescence and deliquescence of aerosol particles can be observed visually and determined quantitatively. Different LLPS mechanisms may dominate successively in mixed organic–inorganic particles. The formation of more concentrated inorganic inclusions may cause secondary LLPS. Furthermore, high inorganic factions may result in an inorganic salt crust enclosing the separated organic phases.
Zhaobin Sun, Xiujuan Zhao, Ziming Li, Guiqian Tang, and Shiguang Miao
Atmos. Chem. Phys., 21, 8863–8882,Short summary
Different weather types will shape significantly different structures of the pollution boundary layer. The findings of this study allow us to understand the inherent difference among heavy pollution boundary layers; in addition, they reveal the formation mechanism of haze pollution from an integrated synoptic-scale and boundary layer structure perspective.
Thomas Bjerring Kristensen, John Falk, Robert Lindgren, Christina Andersen, Vilhelm B. Malmborg, Axel C. Eriksson, Kimmo Korhonen, Ricardo Luis Carvalho, Christoffer Boman, Joakim Pagels, and Birgitta Svenningsson
Atmos. Chem. Phys., 21, 8023–8044,Short summary
Residential biomass combustion is a major anthropogenic source of aerosol particles on regional and global scales. Nevertheless, little is known about those aerosol particles' ability to act as cloud condensation nuclei (CCN) and thus influence cloud properties and climate. Our study shows a strong link between the potassium content in the fuel and emissions of CCN for different stove technologies. Previous studies may have underestimated the anthropogenic climate impact of these emissions.
Meri Räty, Otso Peräkylä, Matthieu Riva, Lauriane Quéléver, Olga Garmash, Matti Rissanen, and Mikael Ehn
Atmos. Chem. Phys., 21, 7357–7372,Short summary
Cyclohexene resembles certain relatively complex compounds in the atmosphere that through oxidation produce vapours that take part in aerosol formation. We studied the highly oxygenated organic molecules (HOMs) formed in cyclohexene ozonolysis, the relationship between their chemical composition and their tendency to condense onto seed aerosol, as well as the effect of NOx pollutants on their signals. Two existing models were also tested for their ability to predict the volatility of the HOMs.
Chao Peng, Patricia N. Razafindrambinina, Kotiba A. Malek, Lanxiadi Chen, Weigang Wang, Ru-Jin Huang, Yuqing Zhang, Xiang Ding, Maofa Ge, Xinming Wang, Akua A. Asa-Awuku, and Mingjin Tang
Atmos. Chem. Phys., 21, 7135–7148,Short summary
Organosulfates are important constituents in tropospheric aerosol particles, but their hygroscopic properties and cloud condensation nuclei activities are not well understood. In our work, three complementary techniques were employed to investigate the interactions of 11 organosulfates with water vapor under sub- and supersaturated conditions.
Alexis Dépée, Pascal Lemaitre, Thomas Gelain, Marie Monier, and Andrea Flossmann
Atmos. Chem. Phys., 21, 6945–6962,Short summary
Present article describe a new In-Cloud Aerosol Scavenging Experiment (In-CASE) that has been conceived to measure the collection efficiency of submicron aerosol particles by cloud droplets. The present article focuses on the influence of phoretic effects on the collection efficiency.
Robert Wagner, Luisa Ickes, Allan K. Bertram, Nora Els, Elena Gorokhova, Ottmar Möhler, Benjamin J. Murray, Nsikanabasi Silas Umo, and Matthew E. Salter
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
Sea spray aerosol particles are a mixture of inorganic salts and organic matter from phytoplankton organisms. At low temperatures in the upper troposphere, both inorganic and organic constituents can induce the formation of ice crystals and thereby impact cloud properties and climate. In this study, we performed experiments in a cloud simulation chamber with particles produced from Arctic seawater samples to quantify the relative contribution of inorganic and organic species in ice formation.
Soleil E. Worthy, Anand Kumar, Yu Xi, Jingwei Yun, Jessie Chen, Cuishan Xu, Victoria E. Irish, Pierre Amato, and Allan K. Bertram
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
We studied the effect of (NH4)2SO4 on the immersion freezing of non-mineral dust ice nucleating substances (INSs) and mineral dusts. (NH4)2SO4 had no effect on the median freezing temperature of nine of the ten tested non-mineral dust INSs, slightly decreased that of the other, and increased that of all the mineral dusts. The difference in the response of mineral dust and non-mineral dust INSs to (NH4)2SO4 suggests that they nucleate ice and/or interact with (NH4)2SO4 via different mechanisms.
Jingchuan Chen, Zhijun Wu, Jie Chen, Naama Reicher, Xin Fang, Yinon Rudich, and Min Hu
Atmos. Chem. Phys., 21, 3491–3506,Short summary
Asian mineral dust is a crucial contributor to global ice-nucleating particles (INPs), while its size-resolved information on freezing activity is extremely rare. Here we conducted the first known INP measurements of size-resolved airborne East Asian dust particles. An explicit size dependence of both INP concentration and surface ice-active-site density was observed. The new parameterizations can be widely applied in models to better characterize and predict ice nucleation activities of dust.
Georgia Michailoudi, Jack J. Lin, Hayato Yuzawa, Masanari Nagasaka, Marko Huttula, Nobuhiro Kosugi, Theo Kurtén, Minna Patanen, and Nønne L. Prisle
Atmos. Chem. Phys., 21, 2881–2894,Short summary
This study provides insight into hydration of two significant atmospheric compounds, glyoxal and methylglyoxal. Using synchrotron radiation excited X-ray absorption spectroscopy, we confirm that glyoxal is fully hydrated in water, and for the first time, we experimentally detect enol structures in aqueous methylglyoxal. Our results support the contribution of these compounds to secondary organic aerosol formation, known to have a large uncertainty in atmospheric models and climate predictions.
Jianzhong Sun, Yuzhe Zhang, Guorui Zhi, Regina Hitzenberger, Wenjing Jin, Yingjun Chen, Lei Wang, Chongguo Tian, Zhengying Li, Rong Chen, Wen Xiao, Yuan Cheng, Wei Yang, Liying Yao, Yang Cao, Duo Huang, Yueyuan Qiu, Jiali Xu, Xiaofei Xia, Xin Yang, Xi Zhang, Zheng Zong, Yuchun Song, and Changdong Wu
Atmos. Chem. Phys., 21, 2329–2341,Short summary
Brown carbon (BrC) emission factors from household biomass fuels were measured with an integrating sphere optics approach supported by iterative calculations. A novel algorithm to directly estimate the absorption contribution of BrC relative to that of BrC + black carbon (FBrC) was proposed based purely on the absorption exponent (AAE) (FBrC = 0.5519 lnAAE + 0.0067). The FBrC for household biomass fuels was as high as 50.8 % across the strongest solar spectral range of 350−850 nm.
Weigang Wang, Ting Lei, Andreas Zuend, Hang Su, Yafang Cheng, Yajun Shi, Maofa Ge, and Mingyuan Liu
Atmos. Chem. Phys., 21, 2179–2190,Short summary
Aerosol mixing state regulates the interactions between water molecules and particles and thus controls aerosol activation and hygroscopic growth, which thereby influences visibility degradation, cloud formation, and its radiative forcing. However, there are few studies attempting to investigate their interactions with water molecules. Here, we investigated the effect of organic coatings on the hygroscopic behavior of the inorganic core.
Sabin Kasparoglu, Ying Li, Manabu Shiraiwa, and Markus D. Petters
Atmos. Chem. Phys., 21, 1127–1141,Short summary
Viscosity is important because it determines the lifetime, impact, and fate of particulate matter. We collected new data to rigorously test a framework that is used to constrain the phase state in global simulations. We find that the framework is accurate as long as appropriate compound specific inputs are available.
Cuiqi Zhang, Yue Zhang, Martin J. Wolf, Leonid Nichman, Chuanyang Shen, Timothy B. Onasch, Longfei Chen, and Daniel J. Cziczo
Atmos. Chem. Phys., 20, 13957–13984,Short summary
Black carbon (BC) is considered the second most important global warming agent. However, the role of BC aerosol–cloud–climate interactions in the cirrus formation remains uncertain. Our study of selected BC types and sizes suggests that increases in diameter, compactness, and/or surface oxidation of BC particles lead to more efficient ice nucleation (IN) via pore condensation freezing (PCF) pathways，and that coatings of common secondary organic aerosol (SOA) materials can inhibit ice formation.
Luisa Ickes, Grace C. E. Porter, Robert Wagner, Michael P. Adams, Sascha Bierbauer, Allan K. Bertram, Merete Bilde, Sigurd Christiansen, Annica M. L. Ekman, Elena Gorokhova, Kristina Höhler, Alexei A. Kiselev, Caroline Leck, Ottmar Möhler, Benjamin J. Murray, Thea Schiebel, Romy Ullrich, and Matthew E. Salter
Atmos. Chem. Phys., 20, 11089–11117,Short summary
The Arctic is a region where aerosols are scarce. Sea spray might be a potential source of aerosols acting as ice-nucleating particles. We investigate two common phytoplankton species (Melosira arctica and Skeletonema marinoi) and present their ice nucleation activity in comparison with Arctic seawater microlayer samples from different field campaigns. We also aim to understand the aerosolization process of marine biological samples and the potential effect on the ice nucleation activity.
Olli-Pekka Tikkanen, Angela Buchholz, Arttu Ylisirniö, Siegfried Schobesberger, Annele Virtanen, and Taina Yli-Juuti
Atmos. Chem. Phys., 20, 10441–10458,Short summary
We compared the volatility distributions of secondary organic aerosol (SOA) constituents estimated from isothermal evaporation experiments from either particle size change data, by process modelling and global optimization, or from mass spectrometer data with positive matrix factorization analysis. Our results show that, despite the two very different estimation methods, the volatility distributions are comparable if uncertainties are taken into account.
Damon M. Smith, Marc N. Fiddler, Rudra P. Pokhrel, and Solomon Bililign
Atmos. Chem. Phys., 20, 10149–10168,Short summary
Biomass burning aerosol can scatter and absorb light, contributing to the cooling or warming of the planet. The scattering and absorption properties (optical properties) change as aerosol ages and interacts with atmospheric gases. Optical properties also depend on burning conditions, fuel type, and morphology. Africa is a major source of biomass burning aerosols, but there are very few laboratory studies. This study focuses on the optical properties of aerosols from east African biomass fuels.
Dominik Stolzenburg, Mario Simon, Ananth Ranjithkumar, Andreas Kürten, Katrianne Lehtipalo, Hamish Gordon, Sebastian Ehrhart, Henning Finkenzeller, Lukas Pichelstorfer, Tuomo Nieminen, Xu-Cheng He, Sophia Brilke, Mao Xiao, António Amorim, Rima Baalbaki, Andrea Baccarini, Lisa Beck, Steffen Bräkling, Lucía Caudillo Murillo, Dexian Chen, Biwu Chu, Lubna Dada, António Dias, Josef Dommen, Jonathan Duplissy, Imad El Haddad, Lukas Fischer, Loic Gonzalez Carracedo, Martin Heinritzi, Changhyuk Kim, Theodore K. Koenig, Weimeng Kong, Houssni Lamkaddam, Chuan Ping Lee, Markus Leiminger, Zijun Li, Vladimir Makhmutov, Hanna E. Manninen, Guillaume Marie, Ruby Marten, Tatjana Müller, Wei Nie, Eva Partoll, Tuukka Petäjä, Joschka Pfeifer, Maxim Philippov, Matti P. Rissanen, Birte Rörup, Siegfried Schobesberger, Simone Schuchmann, Jiali Shen, Mikko Sipilä, Gerhard Steiner, Yuri Stozhkov, Christian Tauber, Yee Jun Tham, António Tomé, Miguel Vazquez-Pufleau, Andrea C. Wagner, Mingyi Wang, Yonghong Wang, Stefan K. Weber, Daniela Wimmer, Peter J. Wlasits, Yusheng Wu, Qing Ye, Marcel Zauner-Wieczorek, Urs Baltensperger, Kenneth S. Carslaw, Joachim Curtius, Neil M. Donahue, Richard C. Flagan, Armin Hansel, Markku Kulmala, Jos Lelieveld, Rainer Volkamer, Jasper Kirkby, and Paul M. Winkler
Atmos. Chem. Phys., 20, 7359–7372,Short summary
Sulfuric acid is a major atmospheric vapour for aerosol formation. If new particles grow fast enough, they can act as cloud droplet seeds or affect air quality. In a controlled laboratory set-up, we demonstrate that van der Waals forces enhance growth from sulfuric acid. We disentangle the effects of ammonia, ions and particle hydration, presenting a complete picture of sulfuric acid growth from molecular clusters onwards. In a climate model, we show its influence on the global aerosol budget.
Arttu Ylisirniö, Angela Buchholz, Claudia Mohr, Zijun Li, Luis Barreira, Andrew Lambe, Celia Faiola, Eetu Kari, Taina Yli-Juuti, Sergey A. Nizkorodov, Douglas R. Worsnop, Annele Virtanen, and Siegfried Schobesberger
Atmos. Chem. Phys., 20, 5629–5644,Short summary
We studied the chemical composition and volatility of secondary organic aerosol (SOA) particles formed from emissions of Scots pines and compared those results to SOA formed from α-pinene and from a sesquiterpene mixture. We found that SOA formed from single precursors cannot capture the properties of SOA formed from real plant emissions.
Wenyu Zhang, Weigang Wang, Junling Li, Chao Peng, Kun Li, Li Zhou, Bo Shi, Yan Chen, Mingyuan Liu, and Maofa Ge
Atmos. Chem. Phys., 20, 4477–4492,Short summary
We investigated the effect of SO2 under different humidities on optical properties of toluene-derived SOA under four conditions with CRDs and PAX at 532 and 375 nm, respectively. Our results showed that SO2 under different humidities can change the refractive complex index of toluene SOA by influencing the multiphase processes and altering the aerosol chemical compositions. Different atmospheric conditions could affect the properties of toluene SOA, as well as the global radiative balance.
Junteng Wu, Alessandro Faccinetto, Symphorien Grimonprez, Sébastien Batut, Jérôme Yon, Pascale Desgroux, and Denis Petitprez
Atmos. Chem. Phys., 20, 4209–4225,Short summary
Soot particles released during anthropogenic activities may lead to positive direct or negative indirect climate forcing depending on their aging in the atmosphere. The latter occurs whenever soot particles act as cloud condensation nuclei (CCN) and trigger the formation of persistent clouds. Herein, we investigate the impact of the size distribution and morphology of freshly emitted soot particles on their aging process and propose a model to quantitatively predict their efficiency as CCN.
Otso Peräkylä, Matthieu Riva, Liine Heikkinen, Lauriane Quéléver, Pontus Roldin, and Mikael Ehn
Atmos. Chem. Phys., 20, 649–669,Short summary
Highly oxygenated organic molecules have been suggested to form a large part of secondary organic aerosol. However, with their exotic structures, their volatilities are not well known, making their exact role in particle formation hard to assess. In laboratory experiments, we found the volatility of HOMs formed in the ozonolysis of the monoterpene alpha-pinene to be in the middle of earlier estimates. The volatilities of HOMs could be well explained in terms of their molecular formulae.
Joel C. Corbin and Martin Gysel-Beer
Atmos. Chem. Phys., 19, 15673–15690,Short summary
We review the literature to refine the definition of "tar balls" (or tar particles). Then, using a marine-engine data set, we show that a standard SP2 can identify tar particles in two ways, as evaporating and non-incandescing (30 % of tar particles by number) or incandescing particles which scatter more light than soot at incandescence (70 % of tar particles by number). To our knowledge, no other technique can provide in situ, real-time evidence for the presence of tar particles in an aerosol.
Claudia Di Biagio, Paola Formenti, Yves Balkanski, Lorenzo Caponi, Mathieu Cazaunau, Edouard Pangui, Emilie Journet, Sophie Nowak, Meinrat O. Andreae, Konrad Kandler, Thuraya Saeed, Stuart Piketh, David Seibert, Earle Williams, and Jean-François Doussin
Atmos. Chem. Phys., 19, 15503–15531,Short summary
This paper presents a new dataset of laboratory measurements of the shortwave (SW) spectral complex refractive index and single-scattering albedo (SSA) for global mineral dust aerosols of varying origin and composition. Our results show that the dust refractive index and SSA vary strongly from source to source, mostly due to particle iron content changes. We recommend that source-dependent values of the SW spectral refractive index and SSA be used in models and remote sensing applications.
Courtney D. Hatch, Paul R. Tumminello, Megan A. Cassingham, Ann L. Greenaway, Rebecca Meredith, and Matthew J. Christie
Atmos. Chem. Phys., 19, 13581–13589,Short summary
Atmospheric mineral dust has been identified as an important contributor to cloud formation and cloud properties that influence the Earth's climate, yet experimental measurements of climate model parameters currently disagree. This study demonstrates current best practices for analyzing water adsorption measurements, resulting in significantly improved agreement among experimental practices. As such, more accurate parameters can be used to improve simulations of aerosol climate effects.
Mijung Song, Adrian M. Maclean, Yuanzhou Huang, Natalie R. Smith, Sandra L. Blair, Julia Laskin, Alexander Laskin, Wing-Sy Wong DeRieux, Ying Li, Manabu Shiraiwa, Sergey A. Nizkorodov, and Allan K. Bertram
Atmos. Chem. Phys., 19, 12515–12529,
Leonid Nichman, Martin Wolf, Paul Davidovits, Timothy B. Onasch, Yue Zhang, Doug R. Worsnop, Janarjan Bhandari, Claudio Mazzoleni, and Daniel J. Cziczo
Atmos. Chem. Phys., 19, 12175–12194,Short summary
Previous studies showed widespread ice nucleation activity of soot. In this systematic study we investigated the factors that affect the heterogeneous ice nucleation activity of soot surrogates in the cirrus cloud regime. Our observations are consistent with an ice nucleation mechanism of pore condensation followed by freezing. The results show significant variations in ice nucleation activity as a function of size, morphology, and surface chemistry of the black-carbon-containing particles.
Martin Schnaiter, Claudia Linke, Inas Ibrahim, Alexei Kiselev, Fritz Waitz, Thomas Leisner, Stefan Norra, and Till Rehm
Atmos. Chem. Phys., 19, 10829–10844,Short summary
When combustion particles are deposited to the ground, they darken Earth's snow and ice surfaces by even tiny quantities. This darkening reduces the back reflection of sunlight and induces an additional climate warming. Particles from fresh snow samples were investigated according to their light absorption strength. Enhanced absorption was found in the snow that cannot fully be attributed to combustion particles. Dust and biogenic matter are likely the cause of this additional snow darkening.
Olli-Pekka Tikkanen, Väinö Hämäläinen, Grazia Rovelli, Antti Lipponen, Manabu Shiraiwa, Jonathan P. Reid, Kari E. J. Lehtinen, and Taina Yli-Juuti
Atmos. Chem. Phys., 19, 9333–9350,Short summary
We assessed how well the organic aerosol particle composition and viscosity can be captured by optimizing process models to match particle evaporation data. We performed the analysis for both artificial and real evaporation data and tested two optimization algorithms. Our findings show that the optimization method yields a good estimate for the studied properties. The timescale of the evaporation data and particle size was found to be important in identifying the volatility of organic compounds.
Miska Olin, Jenni Alanen, Marja R. T. Palmroth, Topi Rönkkö, and Miikka Dal Maso
Atmos. Chem. Phys., 19, 6367–6388,Short summary
The mechanism for new particle formation (NPF) in vehicle exhaust is currently unknown. This study focuses on determining the NPF rate in vehicle exhaust caused by sulfuric acid, which is the most promising candidate involved in the NPF process. The NPF rate function obtained in this study helps in examining the NPF mechanism in exhaust plumes, and it can also be used to improve air quality models. The results also imply that the NPF process cannot be fully explained by sulfuric acid only.
Elena C. Maters, Donald B. Dingwell, Corrado Cimarelli, Dirk Müller, Thomas F. Whale, and Benjamin J. Murray
Atmos. Chem. Phys., 19, 5451–5465,Short summary
This experimental study investigates the influence of volcanic ash chemical composition, crystallinity, and mineralogy on its ability to promote freezing of supercooled water. The results indicate that crystals in ash play a key role in this process and suggest that feldspars and perhaps pyroxenes in ash may be highly ice-active. These findings contribute to improving understanding of the potential of ash emissions from different explosive eruptions to impact ice formation in the atmosphere.
Zamin A. Kanji, Ryan C. Sullivan, Monika Niemand, Paul J. DeMott, Anthony J. Prenni, Cédric Chou, Harald Saathoff, and Ottmar Möhler
Atmos. Chem. Phys., 19, 5091–5110,Short summary
The ice nucleation ability of two natural desert dusts coated with a proxy of secondary organic aerosol is presented for temperatures and relative humidity conditions relevant for mixed-phase clouds. We find that at the tested conditions, there is no effect on the ice nucleation ability of the particles due to the organic coating. Furthermore, the two dust samples do not show variability within measurement uncertainty. Particle size and surface area may play a role in any difference observed.
Nønne L. Prisle, Jack J. Lin, Sara Purdue, Haisheng Lin, J. Carson Meredith, and Athanasios Nenes
Atmos. Chem. Phys., 19, 4741–4761,Short summary
We measure surface activity and cloud-forming potential of pollenkitt, an organic mixture coating pollen grains. Cloud droplet formation is affected through both surface tension and bulk depletion, with a consistent particle size-dependent signature. We observe nonideal solution effects in pollenkitt mixtures with ammonium sulfate salt. Our results suggest sensitivity of general water interactions, including cloud formation by pollen and their fragments, to both atmospheric humidity and aging.
Zhicong Yin, Huijun Wang, Yuyan Li, Xiaohui Ma, and Xinyu Zhang
Atmos. Chem. Phys., 19, 3857–3871,Short summary
Summer surface ozone pollution has rapidly intensified recently, damaging human and ecosystem health. This study aims to examine the large-scale atmospheric circulations associated with the interannual variation in summer surface O3 pollution in North China based on long-term meteorological observations. The impacts of Arctic sea ice were also revealed. The outcomes may provide a basis for understanding the interannual variation of 03 pollution and its seasonal to interannual prediction.
Ankit Tandon, Nicholas E. Rothfuss, and Markus D. Petters
Atmos. Chem. Phys., 19, 3325–3339,Short summary
Organic compounds may form a barrier to condensation. Such barriers have been hypothesized to prevent water and other substances from mixing with salt cores. This will hinder the particles' ability to aid cloud formation of < 100 nm particles. Here we perform experiments encasing particles in plastic shells akin to water bottles. Against expectations, the plastic shell did not alter the droplet activation behavior of the encased particles. Water appears to readily permeate the plastic shell.
James F. Davies, Andreas Zuend, and Kevin R. Wilson
Atmos. Chem. Phys., 19, 2933–2946,Short summary
The formation of cloud droplets involves the condensation of water onto preexisting particles in the atmosphere. The efficiency of this process depends on the nature of the particles, and recent work has shown that organic-rich particles may exhibit a suppressed surface tension that promotes the formation of cloud droplets. In this technical note, we discuss the mechanism for this and highlight the evolution of surface tension as the key factor in the extent of surface effects.
Nathan J. Janechek, Rachel F. Marek, Nathan Bryngelson, Ashish Singh, Robert L. Bullard, William H. Brune, and Charles O. Stanier
Atmos. Chem. Phys., 19, 1649–1664,Short summary
Cyclic volatile methyl siloxanes (cVMSs) are widely used chemicals in personal care products which can undergo oxidation to generate secondary organic aerosol. In this work, cVMS oxidation aerosols were generated using a photochemical chamber and the physical properties characterized. The aerosol yield, volatility, hygroscopicity, morphology, elemental composition, and proposed parameters for treatment as secondary organic aerosol in atmospheric models are provided.
Jian Wang, John E. Shilling, Jiumeng Liu, Alla Zelenyuk, David M. Bell, Markus D. Petters, Ryan Thalman, Fan Mei, Rahul A. Zaveri, and Guangjie Zheng
Atmos. Chem. Phys., 19, 941–954,Short summary
Earlier studies showed organic hygroscopicity increases with oxidation level. Such increases have been attributed to higher water solubility for more oxidized organics. By systematically varying the water content of activating droplets, we show that for secondary organic aerosols, essentially all organics are dissolved at the point of droplet activation. Therefore, the organic hygroscopicity is not limited by solubility but is dictated mainly by the molecular weight of organic species.
Nivedita K. Kumar, Joel C. Corbin, Emily A. Bruns, Dario Massabó, Jay G. Slowik, Luka Drinovec, Griša Močnik, Paolo Prati, Athanasia Vlachou, Urs Baltensperger, Martin Gysel, Imad El-Haddad, and André S. H. Prévôt
Atmos. Chem. Phys., 18, 17843–17861,Short summary
It is clear that considerable uncertainties still exist in understanding the magnitude of aerosol absorption on a global scale and its contribution to global warming. This manuscript provides a comprehensive assessment of the optical absorption by organic aerosols (brown carbon) from residential wood combustion as a function of atmospheric aging.
Yue Peng, Hong Wang, Yubin Li, Changwei Liu, Tianliang Zhao, Xiaoye Zhang, Zhiqiu Gao, Tong Jiang, Huizheng Che, and Meng Zhang
Atmos. Chem. Phys., 18, 17421–17435,Short summary
Two surface layer schemes are evaluated in eastern China based on observational flux data. The results indicate that the Li scheme better describes regional atmosphere stratification compared with the MM5 scheme, especially for the transition stage from unstable to stable atmosphere conditions, corresponding to PM2.5 accumulation. Our research suggests the potential improved possibilities for severe haze prediction in eastern China by coupling Li online into atmosphere chemical models.
Dawei Hu, David Topping, and Gordon McFiggans
Atmos. Chem. Phys., 18, 14925–14937,Short summary
Co-condensation of inorganic or organic vapours on growing droplets could significantly enhance both CCN and cloud droplet number concentration, thereby influencing climate. Until now, there has been very few direct observational evidence of this process. We exposed involatile inorganic particles to a moist atmosphere containing a controlled amount of an organic semi-volatile vapour. We measured a much greater growth of the particles than if they had only been exposed to water vapour.
Maryam Dalirian, Arttu Ylisirniö, Angela Buchholz, Daniel Schlesinger, Johan Ström, Annele Virtanen, and Ilona Riipinen
Atmos. Chem. Phys., 18, 12477–12489,Short summary
Atmospheric black carbon (BC) particles are a concern due to their impact on air quality and climate. Their net climate effect is, however, still uncertain. In this study, laboratory measurements were performed to investigate cloud condensation nuclei (CCN) activity of BC particles, in pure state or coated by various organic species. Our results show that existing theories have potential in describing the CCN activation of atmospheric BC mixed with soluble pollutants.
Sara D. Forestieri, Taylor M. Helgestad, Andrew T. Lambe, Lindsay Renbaum-Wolff, Daniel A. Lack, Paola Massoli, Eben S. Cross, Manvendra K. Dubey, Claudio Mazzoleni, Jason S. Olfert, Arthur J. Sedlacek III, Andrew Freedman, Paul Davidovits, Timothy B. Onasch, and Christopher D. Cappa
Atmos. Chem. Phys., 18, 12141–12159,Short summary
We characterized optical properties of flame-derived black carbon particles and interpret our observations through the use of Mie theory and Rayleigh–Debye–Gans theory. We determined that the mass absorption coefficient is independent of particle collapse and use this to derive theory- and wavelength-specific refractive indices for black carbon (BC). We demonstrate the inadequacy of Mie theory and suggest an alternative approach for atmospheric models to better represent light absorption by BC.
Mijung Song, Suhan Ham, Ryan J. Andrews, Yuan You, and Allan K. Bertram
Atmos. Chem. Phys., 18, 12075–12084,
Sara D. Forestieri, Sean M. Staudt, Thomas M. Kuborn, Katharine Faber, Christopher R. Ruehl, Timothy H. Bertram, and Christopher D. Cappa
Atmos. Chem. Phys., 18, 10985–11005,Short summary
Our work establishes how surface tension reduction influences droplet growth and activation of simple sea spray mimics (NaCl coated with fatty acids). Fatty acids can substantially reduce droplet surface tension near activation but have limited impact on activation. Coating of NaCl by palmitic acid (a wax) impedes water uptake, but this impedance is removed if oleic acid (a liquid) is mixed in. The properties that surface-active compounds need to impact activation are theoretically examined.
Xiangyu Pei, Mattias Hallquist, Axel C. Eriksson, Joakim Pagels, Neil M. Donahue, Thomas Mentel, Birgitta Svenningsson, William Brune, and Ravi Kant Pathak
Atmos. Chem. Phys., 18, 9845–9860,Short summary
The findings in this study show that morphological transformation of soot occurs via two key complementary and sequential processes, i.e., void filling in the particle and its diameter growth. To quantify the state of morphological transformation, i.e., the utilization of material for filling and growth during the condensation processes, a framework was developed which can further be utilized to quantify the effect of condensed material on the optical and hygroscopic properties of soot.
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In this study, we use a new laser imaging nephelometer to measure the bulk aerosol scattering phase function for biomass burning aerosol from controlled fires. By comparing measurements to models for spherical and fractal particles, we demonstrate that the dominant morphology varies by fuel type. This instrument has unique capabilities to directly measure how morphology affects optical properties, and can be used in the future for important validations of remote sensing retrievals.
In this study, we use a new laser imaging nephelometer to measure the bulk aerosol scattering...