| Literature DB >> 27225126 |
Jasmin Tröstl1, Wayne K Chuang2, Hamish Gordon3, Martin Heinritzi4, Chao Yan5, Ugo Molteni1, Lars Ahlm6, Carla Frege1, Federico Bianchi1,5,7, Robert Wagner5, Mario Simon4, Katrianne Lehtipalo1,5, Christina Williamson4,8, Jill S Craven9, Jonathan Duplissy5,10, Alexey Adamov5, Joao Almeida3, Anne-Kathrin Bernhammer11,12, Martin Breitenlechner11,12, Sophia Brilke4, Antònio Dias3, Sebastian Ehrhart3, Richard C Flagan9, Alessandro Franchin5, Claudia Fuchs1, Roberto Guida3, Martin Gysel1, Armin Hansel11,12, Christopher R Hoyle1,13, Tuija Jokinen5, Heikki Junninen5, Juha Kangasluoma5, Helmi Keskinen5,14, Jaeseok Kim14, Manuel Krapf1, Andreas Kürten4, Ari Laaksonen14,15, Michael Lawler14,16, Markus Leiminger4, Serge Mathot3, Ottmar Möhler17, Tuomo Nieminen5,10, Antti Onnela3, Tuukka Petäjä5, Felix M Piel4, Pasi Miettinen14, Matti P Rissanen5, Linda Rondo4, Nina Sarnela5, Siegfried Schobesberger5, Kamalika Sengupta18, Mikko Sipilä5, James N Smith14,19, Gerhard Steiner5,11,20, Antònio Tomè21, Annele Virtanen14, Andrea C Wagner4, Ernest Weingartner1, Daniela Wimmer4,5, Paul M Winkler20, Penglin Ye2, Kenneth S Carslaw18, Joachim Curtius4, Josef Dommen1, Jasper Kirkby3,4, Markku Kulmala5, Ilona Riipinen6, Douglas R Worsnop5,10,22, Neil M Donahue2,5, Urs Baltensperger1.
Abstract
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-Köhler 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.Entities:
Year: 2016 PMID： 27225126 DOI： 10.1038/nature18271
Source DB: PubMed Journal: Nature ISSN： 0028-0836 Impact factor: 49.962