ALBERT

Description: We report comprehensive, demonstrably contaminant-free measurements of binary particle formation rates by sulfuric acid and water for neutral and ion-induced pathways conducted in the CERN CLOUD chamber. The recently developed Atmospheric Pressure interface-Time Of Flight-Mass Spectrometer was used to detect contaminants in charged clusters and to identify runs free of any contaminants. Four parameters were varied to cover ambient conditions: sulfuric acid concentration (10 5 to 10 9 molecules cm −3 ), relative humidity (11% to 58%), temperature (207K to 299K), and total ion concentration (0 to 6800 ions cm −3 ). Formation rates were directly measured with novel instruments at sizes close to the critical cluster size (mobility size of 1.3 nm to 3.2 nm). We compare our results with predictions from Classical Nucleation Theory normalized by Quantum Chemical calculation (QC-normalized CNT), which is described in a companion paper. The formation rates predicted by the QC-normalized CNT were extended from critical cluster sizes to measured sizes using the UHMA2 sectional particle microphysics model. Our results show, for the first time, good agreement between predicted and measured particle formation rates for the binary (neutral and ion-induced) sulfuric acid- water system. Formation rates increase with RH, sulfuric acid and ion concentrations and decrease with temperature at fixed RH and sulfuric acid concentration. Under atmospheric conditions neutral particle formation dominates at low temperatures, while ion-induced particle formation dominates at higher temperatures. The good agreement between the theory and our comprehensive data set gives confidence in using the QC-normalized CNT as a powerful tool to study neutral and ion-induced binary particle formation in atmospheric modeling.

Description: Sulfuric acid is widely recognized as a very important substance driving atmospheric aerosol nucleation. Based on quantum chemical calculations it has been suggested that the quantitative detection of gas phase sulfuric acid (H 2 SO 4 ) by use of Chemical Ionization Mass Spectrometry (CIMS) could be biased in the presence of gas phase amines such as dimethylamine (DMA). An experiment (CLOUD7 campaign) was set up at the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber to investigate the quantitative detection of H 2 SO 4 in the presence of dimethylamine by CIMS at atmospherically relevant concentrations. For the first time in the CLOUD experiment, the monomer sulfuric acid concentration was measured by a CIMS and by two CI-APi-TOF (Chemical Ionization-Atmospheric Pressure interface-Time Of Flight) mass spectrometers. In addition, neutral sulfuric acid clusters were measured with the CI-APi-TOFs. The CLOUD7 measurements show that in the presence of dimethylamine (〈5 to 70 pptv) the sulfuric acid monomer measured by the CIMS represents only a fraction of the total H 2 SO 4 , contained in the monomer and the clusters, that is available for particle growth. Although it was found that the addition of dimethylamine dramatically changes the H 2 SO 4 cluster distribution compared to binary (H 2 SO 4 -H 2 O) conditions, the CIMS detection efficiency does not seem to depend substantially on whether an individual H 2 SO 4 monomer is clustered with a DMA molecule. The experimental observations are supported by numerical simulations based on A Self-contained Atmospheric chemistry coDe (ASAD) coupled with a molecular process model (Sulfuric Acid Water NUCleation, SAWNUC) operated in the kinetic limit.

Description: Organic aerosol (OA) particles affect climate forcing and human health, but their sources and evolution remain poorly characterized. We present a unifying model framework describing the atmospheric evolution of OA that is constrained by high-time-resolution measurements of its composition, volatility, and oxidation state. OA and OA precursor gases evolve by becoming increasingly oxidized, less volatile, and more hygroscopic, leading to the formation of oxygenated organic aerosol (OOA), with concentrations comparable to those of sulfate aerosol throughout the Northern Hemisphere. Our model framework captures the dynamic aging behavior observed in both the atmosphere and laboratory: It can serve as a basis for improving parameterizations in regional and global models.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jimenez, J L -- Canagaratna, M R -- Donahue, N M -- Prevot, A S H -- Zhang, Q -- Kroll, J H -- DeCarlo, P F -- Allan, J D -- Coe, H -- Ng, N L -- Aiken, A C -- Docherty, K S -- Ulbrich, I M -- Grieshop, A P -- Robinson, A L -- Duplissy, J -- Smith, J D -- Wilson, K R -- Lanz, V A -- Hueglin, C -- Sun, Y L -- Tian, J -- Laaksonen, A -- Raatikainen, T -- Rautiainen, J -- Vaattovaara, P -- Ehn, M -- Kulmala, M -- Tomlinson, J M -- Collins, D R -- Cubison, M J -- Dunlea, E J -- Huffman, J A -- Onasch, T B -- Alfarra, M R -- Williams, P I -- Bower, K -- Kondo, Y -- Schneider, J -- Drewnick, F -- Borrmann, S -- Weimer, S -- Demerjian, K -- Salcedo, D -- Cottrell, L -- Griffin, R -- Takami, A -- Miyoshi, T -- Hatakeyama, S -- Shimono, A -- Sun, J Y -- Zhang, Y M -- Dzepina, K -- Kimmel, J R -- Sueper, D -- Jayne, J T -- Herndon, S C -- Trimborn, A M -- Williams, L R -- Wood, E C -- Middlebrook, A M -- Kolb, C E -- Baltensperger, U -- Worsnop, D R -- New York, N.Y. -- Science. 2009 Dec 11;326(5959):1525-9. doi: 10.1126/science.1180353.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Cooperative Institute for Research in the Environmental Sciences and Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA. jose.jimenez@colorado.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20007897" target="_blank"〉PubMed〈/a〉

Description: Atmospheric nucleation is the dominant source of aerosol particles in the global atmosphere and an important player in aerosol climatic effects. The key steps of this process occur in the sub-2-nanometer (nm) size range, in which direct size-segregated observations have not been possible until very recently. Here, we present detailed observations of atmospheric nanoparticles and clusters down to 1-nm mobility diameter. We identified three separate size regimes below 2-nm diameter that build up a physically, chemically, and dynamically consistent framework on atmospheric nucleation--more specifically, aerosol formation via neutral pathways. Our findings emphasize the important role of organic compounds in atmospheric aerosol formation, subsequent aerosol growth, radiative forcing and associated feedbacks between biogenic emissions, clouds, and climate.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kulmala, Markku -- Kontkanen, Jenni -- Junninen, Heikki -- Lehtipalo, Katrianne -- Manninen, Hanna E -- Nieminen, Tuomo -- Petaja, Tuukka -- Sipila, Mikko -- Schobesberger, Siegfried -- Rantala, Pekka -- Franchin, Alessandro -- Jokinen, Tuija -- Jarvinen, Emma -- Aijala, Mikko -- Kangasluoma, Juha -- Hakala, Jani -- Aalto, Pasi P -- Paasonen, Pauli -- Mikkila, Jyri -- Vanhanen, Joonas -- Aalto, Juho -- Hakola, Hannele -- Makkonen, Ulla -- Ruuskanen, Taina -- Mauldin, Roy L 3rd -- Duplissy, Jonathan -- Vehkamaki, Hanna -- Back, Jaana -- Kortelainen, Aki -- Riipinen, Ilona -- Kurten, Theo -- Johnston, Murray V -- Smith, James N -- Ehn, Mikael -- Mentel, Thomas F -- Lehtinen, Kari E J -- Laaksonen, Ari -- Kerminen, Veli-Matti -- Worsnop, Douglas R -- New York, N.Y. -- Science. 2013 Feb 22;339(6122):943-6. doi: 10.1126/science.1227385.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, University of Helsinki, Finland. markku.kulmala@helsinki.fi〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23430652" target="_blank"〉PubMed〈/a〉

Description: Atmospheric aerosols exert an important influence on climate through their effects on stratiform cloud albedo and lifetime and the invigoration of convective storms. Model calculations suggest that almost half of the global cloud condensation nuclei in the atmospheric boundary layer may originate from the nucleation of aerosols from trace condensable vapours, although the sensitivity of the number of cloud condensation nuclei to changes of nucleation rate may be small. Despite extensive research, fundamental questions remain about the nucleation rate of sulphuric acid particles and the mechanisms responsible, including the roles of galactic cosmic rays and other chemical species such as ammonia. Here we present the first results from the CLOUD experiment at CERN. We find that atmospherically relevant ammonia mixing ratios of 100 parts per trillion by volume, or less, increase the nucleation rate of sulphuric acid particles more than 100-1,000-fold. Time-resolved molecular measurements reveal that nucleation proceeds by a base-stabilization mechanism involving the stepwise accretion of ammonia molecules. Ions increase the nucleation rate by an additional factor of between two and more than ten at ground-level galactic-cosmic-ray intensities, provided that the nucleation rate lies below the limiting ion-pair production rate. We find that ion-induced binary nucleation of H(2)SO(4)-H(2)O can occur in the mid-troposphere but is negligible in the boundary layer. However, even with the large enhancements in rate due to ammonia and ions, atmospheric concentrations of ammonia and sulphuric acid are insufficient to account for observed boundary-layer nucleation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kirkby, Jasper -- Curtius, Joachim -- Almeida, Joao -- Dunne, Eimear -- Duplissy, Jonathan -- Ehrhart, Sebastian -- Franchin, Alessandro -- Gagne, Stephanie -- Ickes, Luisa -- Kurten, Andreas -- Kupc, Agnieszka -- Metzger, Axel -- Riccobono, Francesco -- Rondo, Linda -- Schobesberger, Siegfried -- Tsagkogeorgas, Georgios -- Wimmer, Daniela -- Amorim, Antonio -- Bianchi, Federico -- Breitenlechner, Martin -- David, Andre -- Dommen, Josef -- Downard, Andrew -- Ehn, Mikael -- Flagan, Richard C -- Haider, Stefan -- Hansel, Armin -- Hauser, Daniel -- Jud, Werner -- Junninen, Heikki -- Kreissl, Fabian -- Kvashin, Alexander -- Laaksonen, Ari -- Lehtipalo, Katrianne -- Lima, Jorge -- Lovejoy, Edward R -- Makhmutov, Vladimir -- Mathot, Serge -- Mikkila, Jyri -- Minginette, Pierre -- Mogo, Sandra -- Nieminen, Tuomo -- Onnela, Antti -- Pereira, Paulo -- Petaja, Tuukka -- Schnitzhofer, Ralf -- Seinfeld, John H -- Sipila, Mikko -- Stozhkov, Yuri -- Stratmann, Frank -- Tome, Antonio -- Vanhanen, Joonas -- Viisanen, Yrjo -- Vrtala, Aron -- Wagner, Paul E -- Walther, Hansueli -- Weingartner, Ernest -- Wex, Heike -- Winkler, Paul M -- Carslaw, Kenneth S -- Worsnop, Douglas R -- Baltensperger, Urs -- Kulmala, Markku -- 227463/European Research Council/International -- England -- Nature. 2011 Aug 24;476(7361):429-33. doi: 10.1038/nature10343.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉CERN, CH-1211 Geneva, Switzerland. jasper.kirkby@cern.ch〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21866156" target="_blank"〉PubMed〈/a〉

Description: Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up to half of global cloud condensation nuclei. Aerosols can cause a net cooling of climate by scattering sunlight and by leading to smaller but more numerous cloud droplets, which makes clouds brighter and extends their lifetimes. Atmospheric aerosols derived from human activities are thought to have compensated for a large fraction of the warming caused by greenhouse gases. However, despite its importance for climate, atmospheric nucleation is poorly understood. Recently, it has been shown that sulphuric acid and ammonia cannot explain particle formation rates observed in the lower atmosphere. It is thought that amines may enhance nucleation, but until now there has been no direct evidence for amine ternary nucleation under atmospheric conditions. Here we use the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN and find that dimethylamine above three parts per trillion by volume can enhance particle formation rates more than 1,000-fold compared with ammonia, sufficient to account for the particle formation rates observed in the atmosphere. Molecular analysis of the clusters reveals that the faster nucleation is explained by a base-stabilization mechanism involving acid-amine pairs, which strongly decrease evaporation. The ion-induced contribution is generally small, reflecting the high stability of sulphuric acid-dimethylamine clusters and indicating that galactic cosmic rays exert only a small influence on their formation, except at low overall formation rates. Our experimental measurements are well reproduced by a dynamical model based on quantum chemical calculations of binding energies of molecular clusters, without any fitted parameters. These results show that, in regions of the atmosphere near amine sources, both amines and sulphur dioxide should be considered when assessing the impact of anthropogenic activities on particle formation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Almeida, Joao -- Schobesberger, Siegfried -- Kurten, Andreas -- Ortega, Ismael K -- Kupiainen-Maatta, Oona -- Praplan, Arnaud P -- Adamov, Alexey -- Amorim, Antonio -- Bianchi, Federico -- Breitenlechner, Martin -- David, Andre -- Dommen, Josef -- Donahue, Neil M -- Downard, Andrew -- Dunne, Eimear -- Duplissy, Jonathan -- Ehrhart, Sebastian -- Flagan, Richard C -- Franchin, Alessandro -- Guida, Roberto -- Hakala, Jani -- Hansel, Armin -- Heinritzi, Martin -- Henschel, Henning -- Jokinen, Tuija -- Junninen, Heikki -- Kajos, Maija -- Kangasluoma, Juha -- Keskinen, Helmi -- Kupc, Agnieszka -- Kurten, Theo -- Kvashin, Alexander N -- Laaksonen, Ari -- Lehtipalo, Katrianne -- Leiminger, Markus -- Leppa, Johannes -- Loukonen, Ville -- Makhmutov, Vladimir -- Mathot, Serge -- McGrath, Matthew J -- Nieminen, Tuomo -- Olenius, Tinja -- Onnela, Antti -- Petaja, Tuukka -- Riccobono, Francesco -- Riipinen, Ilona -- Rissanen, Matti -- Rondo, Linda -- Ruuskanen, Taina -- Santos, Filipe D -- Sarnela, Nina -- Schallhart, Simon -- Schnitzhofer, Ralf -- Seinfeld, John H -- Simon, Mario -- Sipila, Mikko -- Stozhkov, Yuri -- Stratmann, Frank -- Tome, Antonio -- Trostl, Jasmin -- Tsagkogeorgas, Georgios -- Vaattovaara, Petri -- Viisanen, Yrjo -- Virtanen, Annele -- Vrtala, Aron -- Wagner, Paul E -- Weingartner, Ernest -- Wex, Heike -- Williamson, Christina -- Wimmer, Daniela -- Ye, Penglin -- Yli-Juuti, Taina -- Carslaw, Kenneth S -- Kulmala, Markku -- Curtius, Joachim -- Baltensperger, Urs -- Worsnop, Douglas R -- Vehkamaki, Hanna -- Kirkby, Jasper -- England -- Nature. 2013 Oct 17;502(7471):359-63. doi: 10.1038/nature12663. Epub 2013 Oct 6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Goethe-University of Frankfurt, Institute for Atmospheric and Environmental Sciences, 60438 Frankfurt am Main, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24097350" target="_blank"〉PubMed〈/a〉

Description: Atmospheric new-particle formation affects climate and is one of the least understood atmospheric aerosol processes. The complexity and variability of the atmosphere has hindered elucidation of the fundamental mechanism of new-particle formation from gaseous precursors. We show, in experiments performed with the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN, that sulfuric acid and oxidized organic vapors at atmospheric concentrations reproduce particle nucleation rates observed in the lower atmosphere. The experiments reveal a nucleation mechanism involving the formation of clusters containing sulfuric acid and oxidized organic molecules from the very first step. Inclusion of this mechanism in a global aerosol model yields a photochemically and biologically driven seasonal cycle of particle concentrations in the continental boundary layer, in good agreement with observations.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Riccobono, Francesco -- Schobesberger, Siegfried -- Scott, Catherine E -- Dommen, Josef -- Ortega, Ismael K -- Rondo, Linda -- Almeida, Joao -- Amorim, Antonio -- Bianchi, Federico -- Breitenlechner, Martin -- David, Andre -- Downard, Andrew -- Dunne, Eimear M -- Duplissy, Jonathan -- Ehrhart, Sebastian -- Flagan, Richard C -- Franchin, Alessandro -- Hansel, Armin -- Junninen, Heikki -- Kajos, Maija -- Keskinen, Helmi -- Kupc, Agnieszka -- Kurten, Andreas -- Kvashin, Alexander N -- Laaksonen, Ari -- Lehtipalo, Katrianne -- Makhmutov, Vladimir -- Mathot, Serge -- Nieminen, Tuomo -- Onnela, Antti -- Petaja, Tuukka -- Praplan, Arnaud P -- Santos, Filipe D -- Schallhart, Simon -- Seinfeld, John H -- Sipila, Mikko -- Spracklen, Dominick V -- Stozhkov, Yuri -- Stratmann, Frank -- Tome, Antonio -- Tsagkogeorgas, Georgios -- Vaattovaara, Petri -- Viisanen, Yrjo -- Vrtala, Aron -- Wagner, Paul E -- Weingartner, Ernest -- Wex, Heike -- Wimmer, Daniela -- Carslaw, Kenneth S -- Curtius, Joachim -- Donahue, Neil M -- Kirkby, Jasper -- Kulmala, Markku -- Worsnop, Douglas R -- Baltensperger, Urs -- New York, N.Y. -- Science. 2014 May 16;344(6185):717-21. doi: 10.1126/science.1243527.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland. ; Department of Physics, University of Helsinki, Helsinki, Finland. ; School of Earth and Environment, University of Leeds, Leeds, UK. ; Institute for Atmospheric and Environmental Sciences, Goethe University of Frankfurt, Frankfurt am Main, Germany. ; Laboratory for Systems, Instrumentation, and Modeling in Science and Technology for Space and the Environment (SIM), University of Lisbon and University of Beira Interior, Lisbon, Portugal. ; Ionicon Analytik GmbH and University of Innsbruck, Institute for Ion and Applied Physics, Innsbruck, Austria. ; CERN (European Organization for Nuclear Research), Geneva, Switzerland. ; Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA. ; Department of Physics, University of Helsinki, Helsinki, Finland. Helsinki Institute of Physics, University of Helsinki, Helsinki, Finland. ; University of Eastern Finland, Kuopio, Finland. ; Faculty of Physics, University of Vienna, Vienna, Austria. ; Solar and Cosmic Ray Research Laboratory, Lebedev Physical Institute, Moscow, Russia. ; Leibniz Institute for Tropospheric Research, Leipzig, Germany. ; Finnish Meteorological Institute, Helsinki, Finland. ; Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA 15213, USA. ; Institute for Atmospheric and Environmental Sciences, Goethe University of Frankfurt, Frankfurt am Main, Germany. CERN (European Organization for Nuclear Research), Geneva, Switzerland. ; Department of Physics, University of Helsinki, Helsinki, Finland. Aerodyne Research Incorporated, Billerica, MA 01821, USA. ; Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland. urs.baltensperger@psi.ch.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24833386" target="_blank"〉PubMed〈/a〉

Description: New particle formation (NPF) is the source of over half of the atmosphere's cloud condensation nuclei, thus influencing cloud properties and Earth's energy balance. Unlike in the planetary boundary layer, few observations of NPF in the free troposphere exist. We provide observational evidence that at high altitudes, NPF occurs mainly through condensation of highly oxygenated molecules (HOMs), in addition to taking place through sulfuric acid-ammonia nucleation. Neutral nucleation is more than 10 times faster than ion-induced nucleation, and growth rates are size-dependent. NPF is restricted to a time window of 1 to 2 days after contact of the air masses with the planetary boundary layer; this is related to the time needed for oxidation of organic compounds to form HOMs. These findings require improved NPF parameterization in atmospheric models.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bianchi, F -- Trostl, J -- Junninen, H -- Frege, C -- Henne, S -- Hoyle, C R -- Molteni, U -- Herrmann, E -- Adamov, A -- Bukowiecki, N -- Chen, X -- Duplissy, J -- Gysel, M -- Hutterli, M -- Kangasluoma, J -- Kontkanen, J -- Kurten, A -- Manninen, H E -- Munch, S -- Perakyla, O -- Petaja, T -- Rondo, L -- Williamson, C -- Weingartner, E -- Curtius, J -- Worsnop, D R -- Kulmala, M -- Dommen, J -- Baltensperger, U -- New York, N.Y. -- Science. 2016 May 25. pii: aad5456.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland. Institute for Atmospheric and Climate Science, ETH Zurich, 8092 Zurich, Switzerland. Department of Physics, University of Helsinki, 00014 Helsinki, Finland. ; Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland. ; Department of Physics, University of Helsinki, 00014 Helsinki, Finland. ; Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dubendorf, Switzerland. ; Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland. WSL (Swiss Federal Institute for Forest, Snow and Landscape Research) Institute for Snow and Avalanche Research SLF, 7260 Davos, Switzerland. ; Department of Physics, University of Helsinki, 00014 Helsinki, Finland. Helsinki Institute of Physics, University of Helsinki, 00014 Helsinki, Finland. ; Tofwerk, 3600 Thun, Switzerland. ; Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany. ; Department of Physics, University of Helsinki, 00014 Helsinki, Finland. Aerodyne Research, Billerica, MA 01821, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27226488" target="_blank"〉PubMed〈/a〉

Description: About half of present-day cloud condensation nuclei originate from atmospheric nucleation, frequently appearing as a burst of new particles near midday. Atmospheric observations show that the growth rate of new particles often accelerates when the diameter of the particles is between one and ten nanometres. In this critical size range, new particles are most likely to be lost by coagulation with pre-existing particles, thereby failing to form new cloud condensation nuclei that are typically 50 to 100 nanometres across. Sulfuric acid vapour is often involved in nucleation but is too scarce to explain most subsequent growth, leaving organic vapours as the most plausible alternative, at least in the planetary boundary layer. Although recent studies predict that low-volatility organic vapours contribute during initial growth, direct evidence has been lacking. The accelerating growth may result from increased photolytic production of condensable organic species in the afternoon, and the presence of a possible Kelvin (curvature) effect, which inhibits organic vapour condensation on the smallest particles (the nano-Kohler theory), has so far remained ambiguous. Here we present experiments performed in a large chamber under atmospheric conditions that investigate the role of organic vapours in the initial growth of nucleated organic particles in the absence of inorganic acids and bases such as sulfuric acid or ammonia and amines, respectively. Using data from the same set of experiments, it has been shown that organic vapours alone can drive nucleation. We focus on the growth of nucleated particles and find that the organic vapours that drive initial growth have extremely low volatilities (saturation concentration less than 10(-4.5) micrograms per cubic metre). As the particles increase in size and the Kelvin barrier falls, subsequent growth is primarily due to more abundant organic vapours of slightly higher volatility (saturation concentrations of 10(-4.5) to 10(-0.5) micrograms per cubic metre). We present a particle growth model that quantitatively reproduces our measurements. Furthermore, we implement a parameterization of the first steps of growth in a global aerosol model and find that concentrations of atmospheric cloud concentration nuclei can change substantially in response, that is, by up to 50 per cent in comparison with previously assumed growth rate parameterizations.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Trostl, Jasmin -- Chuang, Wayne K -- Gordon, Hamish -- Heinritzi, Martin -- Yan, Chao -- Molteni, Ugo -- Ahlm, Lars -- Frege, Carla -- Bianchi, Federico -- Wagner, Robert -- Simon, Mario -- Lehtipalo, Katrianne -- Williamson, Christina -- Craven, Jill S -- Duplissy, Jonathan -- Adamov, Alexey -- Almeida, Joao -- Bernhammer, Anne-Kathrin -- Breitenlechner, Martin -- Brilke, Sophia -- Dias, Antonio -- Ehrhart, Sebastian -- Flagan, Richard C -- Franchin, Alessandro -- Fuchs, Claudia -- Guida, Roberto -- Gysel, Martin -- Hansel, Armin -- Hoyle, Christopher R -- Jokinen, Tuija -- Junninen, Heikki -- Kangasluoma, Juha -- Keskinen, Helmi -- Kim, Jaeseok -- Krapf, Manuel -- Kurten, Andreas -- Laaksonen, Ari -- Lawler, Michael -- Leiminger, Markus -- Mathot, Serge -- Mohler, Ottmar -- Nieminen, Tuomo -- Onnela, Antti -- Petaja, Tuukka -- Piel, Felix M -- Miettinen, Pasi -- Rissanen, Matti P -- Rondo, Linda -- Sarnela, Nina -- Schobesberger, Siegfried -- Sengupta, Kamalika -- Sipila, Mikko -- Smith, James N -- Steiner, Gerhard -- Tome, Antonio -- Virtanen, Annele -- Wagner, Andrea C -- Weingartner, Ernest -- Wimmer, Daniela -- Winkler, Paul M -- Ye, Penglin -- Carslaw, Kenneth S -- Curtius, Joachim -- Dommen, Josef -- Kirkby, Jasper -- Kulmala, Markku -- Riipinen, Ilona -- Worsnop, Douglas R -- Donahue, Neil M -- Baltensperger, Urs -- England -- Nature. 2016 May 25;533(7604):527-31. doi: 10.1038/nature18271.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, CH-5232 Villigen, Switzerland. ; Carnegie Mellon University, Center for Atmospheric Particle Studies, Pittsburgh, Pennsylvania 15213, USA. ; CERN, CH-1211 Geneva, Switzerland. ; Goethe University Frankfurt, Institute for Atmospheric and Environmental Sciences, 60438 Frankfurt am Main, Germany. ; Department of Physics, University of Helsinki, PO Box 64, FI-00014 Helsinki, Finland. ; Department of Applied Environmental Science, University of Stockholm, SE-10961 Stockholm, Sweden. ; Institute for Atmospheric and Climate Science, ETH Zurich, 8092 Zurich, Switzerland. ; Chemical Sciences Division, Earth System Research Laboratory, NOAA, Boulder, Colorado, USA. ; Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA. ; Helsinki Institute of Physics, University of Helsinki, PO Box 64, FI-00014 Helsinki, Finland. ; Institute for Ion and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria. ; Ionicon Analytik GmbH, 6020 Innsbruck, Austria. ; WSL Institute for Snow and Avalanche Research SLF, 7260 Davos, Switzerland. ; University of Eastern Finland, 70211 Kuopio, Finland. ; Finnish Meteorological Institute, 00101 Helsinki, Finland. ; National Center for Atmospheric Research, Atmospheric Chemistry Observations and Modeling Laboratory, Boulder, Colorado 80301, USA. ; Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany. ; School of Earth and Environment, University of Leeds, LS2 9JT Leeds, UK. ; Department of Chemistry, University of California, Irvine, California 92697, USA. ; Faculty of Physics, University of Vienna, 1090 Vienna, Austria. ; SIM, University of Lisbon and University of Beira Interior, 1849-016 Lisbon, Portugal. ; Aerodyne Research, Inc., Billerica, Massachusetts 01821, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27225126" target="_blank"〉PubMed〈/a〉

Description: Atmospheric aerosols and their effect on clouds are thought to be important for anthropogenic radiative forcing of the climate, yet remain poorly understood. Globally, around half of cloud condensation nuclei originate from nucleation of atmospheric vapours. It is thought that sulfuric acid is essential to initiate most particle formation in the atmosphere, and that ions have a relatively minor role. Some laboratory studies, however, have reported organic particle formation without the intentional addition of sulfuric acid, although contamination could not be excluded. Here we present evidence for the formation of aerosol particles from highly oxidized biogenic vapours in the absence of sulfuric acid in a large chamber under atmospheric conditions. The highly oxygenated molecules (HOMs) are produced by ozonolysis of alpha-pinene. We find that ions from Galactic cosmic rays increase the nucleation rate by one to two orders of magnitude compared with neutral nucleation. Our experimental findings are supported by quantum chemical calculations of the cluster binding energies of representative HOMs. Ion-induced nucleation of pure organic particles constitutes a potentially widespread source of aerosol particles in terrestrial environments with low sulfuric acid pollution.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kirkby, Jasper -- Duplissy, Jonathan -- Sengupta, Kamalika -- Frege, Carla -- Gordon, Hamish -- Williamson, Christina -- Heinritzi, Martin -- Simon, Mario -- Yan, Chao -- Almeida, Joao -- Trostl, Jasmin -- Nieminen, Tuomo -- Ortega, Ismael K -- Wagner, Robert -- Adamov, Alexey -- Amorim, Antonio -- Bernhammer, Anne-Kathrin -- Bianchi, Federico -- Breitenlechner, Martin -- Brilke, Sophia -- Chen, Xuemeng -- Craven, Jill -- Dias, Antonio -- Ehrhart, Sebastian -- Flagan, Richard C -- Franchin, Alessandro -- Fuchs, Claudia -- Guida, Roberto -- Hakala, Jani -- Hoyle, Christopher R -- Jokinen, Tuija -- Junninen, Heikki -- Kangasluoma, Juha -- Kim, Jaeseok -- Krapf, Manuel -- Kurten, Andreas -- Laaksonen, Ari -- Lehtipalo, Katrianne -- Makhmutov, Vladimir -- Mathot, Serge -- Molteni, Ugo -- Onnela, Antti -- Perakyla, Otso -- Piel, Felix -- Petaja, Tuukka -- Praplan, Arnaud P -- Pringle, Kirsty -- Rap, Alexandru -- Richards, Nigel A D -- Riipinen, Ilona -- Rissanen, Matti P -- Rondo, Linda -- Sarnela, Nina -- Schobesberger, Siegfried -- Scott, Catherine E -- Seinfeld, John H -- Sipila, Mikko -- Steiner, Gerhard -- Stozhkov, Yuri -- Stratmann, Frank -- Tome, Antonio -- Virtanen, Annele -- Vogel, Alexander L -- Wagner, Andrea C -- Wagner, Paul E -- Weingartner, Ernest -- Wimmer, Daniela -- Winkler, Paul M -- Ye, Penglin -- Zhang, Xuan -- Hansel, Armin -- Dommen, Josef -- Donahue, Neil M -- Worsnop, Douglas R -- Baltensperger, Urs -- Kulmala, Markku -- Carslaw, Kenneth S -- Curtius, Joachim -- England -- Nature. 2016 May 25;533(7604):521-6. doi: 10.1038/nature17953.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Goethe University Frankfurt, Institute for Atmospheric and Environmental Sciences, 60438 Frankfurt am Main, Germany. ; CERN, CH-1211 Geneva, Switzerland. ; Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland. ; Helsinki Institute of Physics, University of Helsinki, FI-00014 Helsinki, Finland. ; School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK. ; Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, CH-5232 Villigen, Switzerland. ; Institute for Ion and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria. ; Onera-The French Aerospace Lab, F-91123 Palaiseau, France. ; SIM, University of Lisbon, 1849-016 Lisbon, Portugal. ; Ionicon Analytik GmbH, 6020 Innsbruck, Austria. ; Institute for Atmospheric and Climate Science, ETH Zurich, CH-8092 Zurich, Switzerland. ; Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA. ; WSL Institute for Snow and Avalanche Research SLF, CH-7260 Davos, Switzerland. ; University of Eastern Finland, FI-70211 Kuopio, Finland. ; Finnish Meteorological Institute, FI-00101 Helsinki, Finland. ; Solar and Cosmic Ray Research Laboratory, Lebedev Physical Institute, 119991 Moscow, Russia. ; University of Leeds, National Centre for Earth Observation, Leeds LS2 9JT, UK. ; Department of Applied Environmental Science, University of Stockholm, SE-10961 Stockholm, Sweden. ; Faculty of Physics, University of Vienna, 1090 Vienna, Austria. ; Leibniz Institute for Tropospheric Research, 04318 Leipzig, Germany. ; University of Beira Interior, 6201-001 Covilha, Portugal. ; Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA. ; Aerodyne Research Inc., Billerica, Massachusetts 01821, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27225125" target="_blank"〉PubMed〈/a〉