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Published August 27, 2017 | Supplemental Material + Published
Journal Article Open

Causes and importance of new particle formation in the present-day and pre-industrial atmospheres

Abstract

New particle formation has been estimated to produce around half of cloud-forming particles in the present-day atmosphere, via gas-to-particle conversion. Here we assess the importance of new particle formation (NPF) for both the present-day and the preindustrial atmospheres. We use a global aerosol model with parametrizations of NPF from previously published CLOUD chamber experiments involving sulfuric acid, ammonia, organic molecules, and ions. We find that NPF produces around 67% of cloud condensation nuclei at 0.2% supersaturation (CCN0.2%) at the level of low clouds in the preindustrial atmosphere (estimated uncertainty range 45–84%) and 54% in the present day (estimated uncertainty range 38–66%). Concerning causes, we find that the importance of biogenic volatile organic compounds (BVOCs) in NPF and CCN formation is greater than previously thought. Removing BVOCs and hence all secondary organic aerosol from our model reduces low-cloud-level CCN concentrations at 0.2% supersaturation by 26% in the present-day atmosphere and 41% in the preindustrial. Around three quarters of this reduction is due to the tiny fraction of the oxidation products of BVOCs that have sufficiently low volatility to be involved in NPF and early growth. Furthermore, we estimate that 40% of preindustrial CCN0.2% are formed via ion-induced NPF, compared with 27% in the present day, although we caution that the ion-induced fraction of NPF involving BVOCs is poorly measured at present. Our model suggests that the effect of changes in cosmic ray intensity on CCN is small and unlikely to be comparable to the effect of large variations in natural primary aerosol emissions.

Additional Information

© 2017 The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Received 24 MAR 2017; Accepted 7 JUL 2017; Accepted article online 10 JUL 2017; Published online 24 AUG 2017. We would like to thank CERN for supporting CLOUD with important technical and financial resources and for providing a particle beam from the CERN Proton Synchrotron. We also thank P. Carrie, L.-P. De Menezes, J. Dumollard, K. Ivanova, F. Josa, I. Krasin, R. Kristic, A. Laassiri, O.S. Maksumov, B. Marichy, H. Martinati, S.V. Mizin, R. Sitals, H.U. Walther, A. Wasem, and M. Wilhelmsson for their important contributions to the experiment. The computer modeling simulations were performed on ARC1 and ARC2, part of the High Performance Computing facilities at the University of Leeds, UK. This work also made use of the POLARIS facility of the N8 HPC Centre of Excellence, provided and funded by the N8 consortium and EPSRC (grant No.EP/K000225/1). The Centre is coordinated by the Universities of Leeds and Manchester. This research has received funding from the EC Seventh Framework Programme (Marie Curie Initial Training Networks "CLOUD-ITN" (215072) and "CLOUD-TRAIN" (316662), the FP7 EU Bacchus project under grant 603445-BACCHUS, and the Horizon 2020 projects CRESCENDO under grant agreement 641816 and the Marie-Sklodowska-Curie project nano-CAVa 656994), ERC-Starting MOCAPAF grant 57360 and ERC Advanced "ATMNUCLE" grant 227463, the German Federal Ministry of Education and Research (projects 01LK0902A and 01LK1222A), the Swiss National Science Foundation (projects 200020_135307 and 206620_141278), the Academy of Finland (Center of Excellence project 1118615 and other projects 135054, 133872, 251427, 139656, 139995, 137749, 141217, 141451, 138951, and 299574), the Finnish Funding Agency for Technology and Innovation, the V.is.l. Foundation, the Nessling Foundation, ERC Consolidator grant "NANODYNAMITE," 616075, the Portuguese Foundation for Science and Technology (project CERN/FP/116387/2010), the Swedish Research Council, Vetenskapsrådet (grant 2011-5120), the Presidium of the Russian Academy of Sciences and Russian Foundation for Basic Research (grants 08-02-91006-CERN and 12-02-91522-CERN), the U.S. National Science Foundation (grants AGS1136479, AGS1447056, AGS1439551, and CHE1012293), the U.S. Department of Energy (grant DE-SC0014469), the Davidow Foundation, and the NERC GASSP project under grant NE/J024252/1. We acknowledge financial support from the Royal Society Wolfson Merit Award. The simulation data presented in this manuscript are available from Zenodo at DOI 10.5281/zenodo.821582. The full NPF parametrizations used, and summaries of the model results, are provided in the supporting information.

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Published - Gordon_et_al-2017-Journal_of_Geophysical_Research__Atmospheres.pdf

Supplemental Material - 2017JD026844-sup-0001-Text_20SI-S01_AA.pdf

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August 21, 2023
Modified:
October 26, 2023