ALBERT

Description: The magnitude of aerosol radiative forcing caused by anthropogenic emissions depends on the baseline state of the atmosphere under pristine preindustrial conditions. Measurements show that particle formation in atmospheric conditions can occur solely from biogenic vapors. Here, we evaluate the potential effect of this source of particles on preindustrial cloud...

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: 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〉

Description: For atmospheric sulfuric acid (SA) concentrations the presence of dimethylamine (DMA) at mixing ratios of several parts per trillion by volume can explain observed boundary layer new particle formation rates. However, the concentration and molecular composition of the neutral (uncharged) clusters have not been reported so far due to the...

Description: Fundamental questions remain about the origin of newly formed atmospheric aerosol particles because data from laboratory measurements have been insufficient to build global models. In contrast, gas-phase chemistry models have been based on laboratory kinetics measurements for decades. Here we build a global model of aerosol formation using extensive laboratory-measured nucleation rates involving sulfuric acid, ammonia, ions and organic compounds. The simulations and a comparison with atmospheric observations show that nearly all nucleation throughout the present-day atmosphere involves ammonia or biogenic organic compounds in addition to sulfuric acid. A significant fraction of nucleation involves ions, but the relatively weak dependence on ion concentrations indicates that for the processes studied variations in cosmic ray intensity do not significantly affect climate via nucleation in the present-day atmosphere. © 2016 American Association for the Advancement of Science.