U
Urmas Hõrrak
Researcher at University of Tartu
Publications - 52
Citations - 3355
Urmas Hõrrak is an academic researcher from University of Tartu. The author has contributed to research in topics: Aerosol & Ion. The author has an hindex of 24, co-authored 51 publications receiving 3015 citations.
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Journal ArticleDOI
General overview: European Integrated project on Aerosol Cloud Climate and Air Quality interactions (EUCAARI) - integrating aerosol research from nano to global scales
Markku Kulmala,Ari Asmi,Hanna Lappalainen,Hanna Lappalainen,Urs Baltensperger,J. L. Brenguier,Maria Cristina Facchini,Hans-Christen Hansson,Øystein Hov,Colin D. O'Dowd,Ulrich Pöschl,Alfred Wiedensohler,R. Boers,Olivier Boucher,Olivier Boucher,G. de Leeuw,G. de Leeuw,H. A. C. Denier van der Gon,Johann Feichter,Radovan Krejci,Paolo Laj,Heikki Lihavainen,Ulrike Lohmann,Gordon McFiggans,Thomas F. Mentel,Christodoulos Pilinis,Ilona Riipinen,Ilona Riipinen,Michael Schulz,Andreas Stohl,Erik Swietlicki,Elisabetta Vignati,Célia Alves,Markus Amann,Markus Ammann,Sylwester Arabas,Paulo Artaxo,Holger Baars,David C. S. Beddows,Robert Bergström,Johan P. Beukes,Merete Bilde,John F. Burkhart,Francesco Canonaco,Simon L. Clegg,Hugh Coe,Suzanne Crumeyrolle,Barbara D'Anna,Stefano Decesari,Stefania Gilardoni,Marc Fischer,A. M. Fjaeraa,Christos Fountoukis,Christian George,L. Gomes,Paul R. Halloran,Thomas Hamburger,Roy M. Harrison,Hartmut Herrmann,Thorsten Hoffmann,Corinna Hoose,Min Hu,Antti-Pekka Hyvärinen,Urmas Hõrrak,Yoshiteru Iinuma,Trond Iversen,Miroslav Josipovic,Maria Kanakidou,Astrid Kiendler-Scharr,Alf Kirkevåg,Gyula Kiss,Zbigniew Klimont,Pekka Kolmonen,Mika Komppula,Jón Egill Kristjánsson,Lauri Laakso,Lauri Laakso,Lauri Laakso,Ari Laaksonen,Ari Laaksonen,Laurent C.-Labonnote,V. A. Lanz,Kari E. J. Lehtinen,Kari E. J. Lehtinen,Luciana V. Rizzo,Risto Makkonen,Hanna E. Manninen,Gavin R. McMeeking,Joonas Merikanto,Andreas Minikin,Sander Mirme,William T. Morgan,Eiko Nemitz,D. O'Donnell,T. S. Panwar,Hanna Pawlowska,Andreas Petzold,Jacobus J. Pienaar,Casimiro Pio,C. Plass-Duelmer,André S. H. Prévôt,Sara C. Pryor,Carly Reddington,G. Roberts,Daniel Rosenfeld,Joshua P. Schwarz,Øyvind Seland,Karine Sellegri,X. J. Shen,Manabu Shiraiwa,Holger Siebert,B. Sierau,David Simpson,David Simpson,J. Y. Sun,David Topping,Peter Tunved,Petri Vaattovaara,Ville Vakkari,J. P. Veefkind,Antoon Visschedijk,Henri Vuollekoski,R. Vuolo,Birgit Wehner,J. Wildt,Simon Woodward,D. R. Worsnop,D. R. Worsnop,G.-J. van Zadelhoff,A. A. Zardini,Kai Zhang,P. G. van Zyl,Veli-Matti Kerminen,Kenneth S. Carslaw,Spyros N. Pandis +134 more
TL;DR: The European Aerosol Cloud Climate and Air Quality Interactions project (EUCAARI) as mentioned in this paper was the first project to study aerosol processes fron nano to global scale and their effects on climate and air quality.
Journal ArticleDOI
EUCAARI ion spectrometer measurements at 12 European sites – analysis of new particle formation events
Hanna E. Manninen,Tuomo Nieminen,Eija Asmi,Stephanie Gagne,S. A. K. Hakkinen,Katrianne Lehtipalo,Pasi Aalto,Marko Vana,Marko Vana,Aadu Mirme,Sander Mirme,Urmas Hõrrak,C. Plass-Dülmer,G. Stange,G. Kiss,András Hoffer,N. Törő,Marcel M. Moerman,Bas Henzing,G. de Leeuw,G. de Leeuw,G. de Leeuw,M. Brinkenberg,Giorgos Kouvarakis,Aikaterini Bougiatioti,Nikos Mihalopoulos,Colin D. O'Dowd,Darius Ceburnis,Almut Arneth,Birgitta Svenningsson,Erik Swietlicki,L. Tarozzi,Stefano Decesari,Maria Cristina Facchini,Wolfram Birmili,A. Sonntag,Alfred Wiedensohler,J. Boulon,Karine Sellegri,Paolo Laj,Martin Gysel,Nicolas Bukowiecki,Ernest Weingartner,G. Wehrle,Ari Laaksonen,Ari Laaksonen,A. Hamed,Jorma Joutsensaari,Tuukka Petäjä,Veli-Matti Kerminen,Veli-Matti Kerminen,Markku Kulmala,Markku Kulmala,Markku Kulmala +53 more
TL;DR: In this paper, the authors present comprehensive results on continuous atmospheric cluster and particle measurements in the size range ∼1-42 nm within the European Integrated project on Aerosol Cloud Climate and Air Quality interactions (EUCAARI) project.
Journal ArticleDOI
Atmospheric ions and nucleation: a review of observations
Anne Hirsikko,Tuomo Nieminen,Stephanie Gagne,Katrianne Lehtipalo,Hanna E. Manninen,Mikael Ehn,Urmas Hõrrak,Veli-Matti Kerminen,Veli-Matti Kerminen,Lauri Laakso,Lauri Laakso,Lauri Laakso,Peter H. McMurry,Aadu Mirme,Sander Mirme,Tuukka Petäjä,Hannes Tammet,Ville Vakkari,Marko Vana,Marko Vana,Markku Kulmala +20 more
TL;DR: In this article, a review of 260 publications on the formation of 2-nm intermediate ions, growth rates of sub-3 nm ions, and information on the chemical composition of the ions is presented.
Journal ArticleDOI
On the roles of sulphuric acid and low-volatility organic vapours in the initial steps of atmospheric new particle formation
Pauli Paasonen,Tuomo Nieminen,Eija Asmi,Hanna E. Manninen,Tuukka Petäjä,C. Plass-Dülmer,H. Flentje,Wolfram Birmili,A. Wiedensohler,Urmas Hõrrak,A. Metzger,A. Hamed,Ari Laaksonen,Maria Cristina Facchini,V.-M. Kerminen,Markku Kulmala,Markku Kulmala +16 more
TL;DR: In this article, the authors analyzed 36 new particle formation events observed at four European measurement sites during EUCAARI campaigns in 2007-2009 and determined the related nucleation coefficients connecting the neutral nucleation rate J with the vapour concentrations in each mechanism.
Journal Article
Annual and size dependent variation of growth rates and ion concentrations in boreal forest
TL;DR: The results indicate that in addition to sulphuric acid, compounds related to photosynthesis participate in the particle growth, especially in the size class 7-20 nm.