H
Helmi Keskinen
Researcher at University of Helsinki
Publications - 48
Citations - 3189
Helmi Keskinen is an academic researcher from University of Helsinki. The author has contributed to research in topics: Particle & Nanoparticle. The author has an hindex of 20, co-authored 46 publications receiving 2643 citations. Previous affiliations of Helmi Keskinen include Finnish Institute of Occupational Health & University of Eastern Finland.
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Journal ArticleDOI
Molecular understanding of sulphuric acid-amine particle nucleation in the atmosphere
Joao Almeida,Joao Almeida,Siegfried Schobesberger,Andreas Kürten,Ismael K. Ortega,Oona Kupiainen-Määttä,Arnaud P. Praplan,Alexey Adamov,António Amorim,F. Bianchi,Martin Breitenlechner,A. David,Josef Dommen,Neil M. Donahue,Andrew J. Downard,Eimear M. Dunne,Jonathan Duplissy,Sebastian Ehrhart,Richard C. Flagan,Alessandro Franchin,Roberto Guida,Jani Hakala,Armin Hansel,Martin Heinritzi,Henning Henschel,Tuija Jokinen,Heikki Junninen,Maija Kajos,Juha Kangasluoma,Helmi Keskinen,Agnieszka Kupc,Theo Kurtén,Alexander N. Kvashin,Ari Laaksonen,Ari Laaksonen,Katrianne Lehtipalo,Markus Leiminger,Johannes Leppä,Ville Loukonen,Vladimir Makhmutov,Serge Mathot,Matthew J. McGrath,Tuomo Nieminen,Tuomo Nieminen,Tinja Olenius,Antti Onnela,Tuukka Petäjä,Francesco Riccobono,Ilona Riipinen,Matti P. Rissanen,Linda Rondo,Taina Ruuskanen,Filipe Duarte Santos,Nina Sarnela,Simon Schallhart,R. Schnitzhofer,John H. Seinfeld,Mario Simon,Mikko Sipilä,Mikko Sipilä,Yuri Stozhkov,Frank Stratmann,António Tomé,Jasmin Tröstl,Georgios Tsagkogeorgas,Petri Vaattovaara,Yrjö Viisanen,Annele Virtanen,Aron Vrtala,Paul E. Wagner,Ernest Weingartner,Heike Wex,Christina Williamson,Daniela Wimmer,Daniela Wimmer,Penglin Ye,Taina Yli-Juuti,Kenneth S. Carslaw,Markku Kulmala,Markku Kulmala,Joachim Curtius,Urs Baltensperger,Douglas R. Worsnop,Hanna Vehkamäki,Jasper Kirkby,Jasper Kirkby +85 more
TL;DR: The 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.
Journal ArticleDOI
The role of low-volatility organic compounds in initial particle growth in the atmosphere
Jasmin Tröstl,Wayne Chuang,Hamish Gordon,Martin Heinritzi,Chao Yan,Ugo Molteni,Lars Ahlm,Carla Frege,F. Bianchi,F. Bianchi,F. Bianchi,Robert Wagner,Mario Simon,Katrianne Lehtipalo,Katrianne Lehtipalo,Christina Williamson,Christina Williamson,Christina Williamson,J. S. Craven,Jonathan Duplissy,Jonathan Duplissy,Alexey Adamov,Joao Almeida,Anne-Kathrin Bernhammer,Martin Breitenlechner,Sophia Brilke,Antonio Dias,Sebastian Ehrhart,Richard C. Flagan,Alessandro Franchin,Claudia Fuchs,Roberto Guida,Martin Gysel,Armin Hansel,Christopher R. Hoyle,Tuija Jokinen,Heikki Junninen,Juha Kangasluoma,Helmi Keskinen,Helmi Keskinen,Helmi Keskinen,Jaeseok Kim,Jaeseok Kim,Manuel Krapf,Andreas Kürten,Ari Laaksonen,Ari Laaksonen,Michael J. Lawler,Michael J. Lawler,Markus Leiminger,Serge Mathot,Ottmar Möhler,Tuomo Nieminen,Tuomo Nieminen,Antti Onnela,Tuukka Petäjä,Felix Piel,Pasi Miettinen,Matti P. Rissanen,Linda Rondo,Nina Sarnela,Siegfried Schobesberger,Siegfried Schobesberger,Kamalika Sengupta,Mikko Sipilä,James N. Smith,James N. Smith,Gerhard Steiner,Gerhard Steiner,Gerhard Steiner,António Tomé,Annele Virtanen,Andrea Christine Wagner,Ernest Weingartner,Ernest Weingartner,Daniela Wimmer,Daniela Wimmer,Paul M. Winkler,Penglin Ye,Kenneth S. Carslaw,Joachim Curtius,Josef Dommen,Jasper Kirkby,Jasper Kirkby,Markku Kulmala,Ilona Riipinen,Douglas R. Worsnop,Douglas R. Worsnop,Neil M. Donahue,Neil M. Donahue,Urs Baltensperger +90 more
TL;DR: It is shown that organic vapours alone can drive nucleation, and a particle growth model is presented that quantitatively reproduces the measurements and implements a parameterization of the first steps of growth in a global aerosol model that can change substantially in response to concentrations of atmospheric cloud concentration nuclei.
Journal ArticleDOI
Oxidation products of biogenic emissions contribute to nucleation of atmospheric particles.
Francesco Riccobono,Siegfried Schobesberger,Catherine E. Scott,Josef Dommen,Ismael K. Ortega,Linda Rondo,Joao Almeida,António Amorim,F. Bianchi,Martin Breitenlechner,A. David,Andrew J. Downard,Eimear M. Dunne,Jonathan Duplissy,Jonathan Duplissy,Sebastian Ehrhart,Richard C. Flagan,Alessandro Franchin,Armin Hansel,Heikki Junninen,Maija Kajos,Helmi Keskinen,Agnieszka Kupc,Andreas Kürten,Alexander N. Kvashin,Ari Laaksonen,Katrianne Lehtipalo,Vladimir Makhmutov,Serge Mathot,Tuomo Nieminen,Tuomo Nieminen,Antti Onnela,Tuukka Petäjä,Arnaud P. Praplan,Filipe Duarte Santos,Simon Schallhart,John H. Seinfeld,Mikko Sipilä,Mikko Sipilä,Dominick V. Spracklen,Yuri Stozhkov,Frank Stratmann,António Tomé,Georgios Tsagkogeorgas,Petri Vaattovaara,Yrjö Viisanen,Aron Vrtala,Paul E. Wagner,Ernest Weingartner,Heike Wex,Daniela Wimmer,Kenneth S. Carslaw,Joachim Curtius,Neil M. Donahue,Jasper Kirkby,Jasper Kirkby,Markku Kulmala,Markku Kulmala,Douglas R. Worsnop,Urs Baltensperger +59 more
TL;DR: It is shown, 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.
Journal ArticleDOI
Molecular understanding of atmospheric particle formation from sulfuric acid and large oxidized organic molecules
Siegfried Schobesberger,Heikki Junninen,F. Bianchi,Gustaf Lönn,Mikael Ehn,Katrianne Lehtipalo,Josef Dommen,Sebastian Ehrhart,Ismael K. Ortega,Alessandro Franchin,Tuomo Nieminen,Francesco Riccobono,Manuel Hutterli,Jonathan Duplissy,Joao Almeida,António Amorim,Martin Breitenlechner,Andrew J. Downard,Eimear M. Dunne,Eimear M. Dunne,Richard C. Flagan,Maija Kajos,Helmi Keskinen,Jasper Kirkby,Agnieszka Kupc,Andreas Kürten,Theo Kurtén,Ari Laaksonen,Ari Laaksonen,Serge Mathot,Antti Onnela,Arnaud P. Praplan,Linda Rondo,Filipe Duarte Santos,Simon Schallhart,R. Schnitzhofer,Mikko Sipilä,António Tomé,Georgios Tsagkogeorgas,Hanna Vehkamäki,Daniela Wimmer,Daniela Wimmer,Urs Baltensperger,Kenneth S. Carslaw,Joachim Curtius,Armin Hansel,Tuukka Petäjä,Markku Kulmala,Neil M. Donahue,Douglas R. Worsnop +49 more
TL;DR: High-resolution mass spectra of ion clusters observed during new particle formation experiments performed at the Cosmics Leaving Outdoor Droplets chamber at the European Organization for Nuclear Research confirm that oxidized organics are involved in both the formation and growth of particles under ambient conditions.
Journal ArticleDOI
The effect of acid-base clustering and ions on the growth of atmospheric nano-particles
Katrianne Lehtipalo,Linda Rondo,Jenni Kontkanen,Siegfried Schobesberger,Tuija Jokinen,Nina Sarnela,Andreas Kürten,Sebastian Ehrhart,Sebastian Ehrhart,Alessandro Franchin,Tuomo Nieminen,Tuomo Nieminen,Francesco Riccobono,Mikko Sipilä,Mikko Sipilä,Taina Yli-Juuti,Taina Yli-Juuti,Jonathan Duplissy,Jonathan Duplissy,Jonathan Duplissy,Alexey Adamov,Lars Ahlm,Joao Almeida,António Amorim,F. Bianchi,F. Bianchi,Martin Breitenlechner,Josef Dommen,Andrew J. Downard,Eimear M. Dunne,Richard C. Flagan,Roberto Guida,Jani Hakala,Armin Hansel,Werner Jud,Juha Kangasluoma,Veli-Matti Kerminen,Helmi Keskinen,Helmi Keskinen,Jaeseok Kim,Jasper Kirkby,Agnieszka Kupc,Oona Kupiainen-Määttä,Ari Laaksonen,Ari Laaksonen,Michael J. Lawler,Michael J. Lawler,Markus Leiminger,Serge Mathot,Tinja Olenius,Ismael K. Ortega,Antti Onnela,Tuukka Petäjä,Arnaud P. Praplan,Arnaud P. Praplan,Matti P. Rissanen,Taina Ruuskanen,Filipe Duarte Santos,Simon Schallhart,R. Schnitzhofer,Mario Simon,James N. Smith,James N. Smith,Jasmin Tröstl,Georgios Tsagkogeorgas,António Tomé,Petri Vaattovaara,Hanna Vehkamäki,Aron Vrtala,Paul E. Wagner,Christina Williamson,Daniela Wimmer,Daniela Wimmer,Paul M. Winkler,Annele Virtanen,Neil M. Donahue,Kenneth S. Carslaw,Urs Baltensperger,Ilona Riipinen,Joachim Curtius,Douglas R. Worsnop,Markku Kulmala,Markku Kulmala +82 more
TL;DR: In this paper, the authors studied nano-particle growth in the Clouds Leaving OUtdoors Droplets (CLOUD) chamber, starting from the formation of molecular clusters and found that atmospheric ions and small acid-base clusters, which are not generally accounted for in the measurement of sulphuric acid vapour, can participate in the growth process.