• DOI:10.1038/nature10343
• Corpus ID: 4326159

Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation

@article{Kirkby2011RoleOS,
  title={Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation},
  author={Jasper Kirkby and Joachim Curtius and Jo{\~a}o Almeida and Eimear M. Dunne and Jonathan Duplissy and Sebastian Ehrhart and Alessandro Franchin and St{\'e}phanie Gagn{\'e} and Luisa Ickes and Andreas K{\"u}rten and Agnieszka Kupc and Axel Metzger and Francesco Riccobono and Linda Rondo and Siegfried Schobesberger and Georgios Tsagkogeorgas and Daniela Wimmer and Ant{\'o}nio Amorim and Federico Bianchi and Martin Breitenlechner and Andr{\'e} David and Josef Dommen and Andrew J. Downard and Mikael Ehn and Richard C. Flagan and Stefan Haider and Armin Hansel and Daniel Hauser and Werner Jud and Heikki Junninen and Fabian Kreissl and Alexander N. Kvashin and Ari Laaksonen and Katrianne Lehtipalo and Jorge Lima and Edward R. Lovejoy and Vladimir Makhmutov and Serge Mathot and Jyri Mikkil{\"a} and Pierre Minginette and Sandra Mogo and Tuomo Nieminen and Antti Onnela and P. Pereira and Tuukka Pet{\"a}j{\"a} and Ralf Schnitzhofer and John H. Seinfeld and Mikko Sipil{\"a} and Y. I. Stozhkov and Frank Stratmann and Ant{\'o}nio Tom{\'e} and Joonas Vanhanen and Yrj{\"o} Viisanen and Aron Vrtala and Paul E. Wagner and H. Walther and Ernest Weingartner and Heike Wex and Paul M. Winkler and Kenneth S. Carslaw and Douglas R. Worsnop and Urs Baltensperger and Markku Kulmala},
  journal={Nature},
  year={2011},
  volume={476},
  pages={429-433}
}

• J. Kirkby, J. Curtius, +60 authors M. Kulmala
• Published 25 August 2011
• Physics, Environmental Science
• Nature

Atmospheric aerosols exert an important influence on climate through their effects on stratiform cloud albedo and lifetime and the invigoration of convective storms. Model calculations suggest that almost half of the global cloud condensation nuclei in the atmospheric boundary layer may originate from the nucleation of aerosols from trace condensable vapours, although the sensitivity of the number of cloud condensation nuclei to changes of nucleation rate may be small. Despite extensive research, fundamental questions remain about the nucleation rate of sulphuric acid particles and the mechanisms responsible, including the roles of galactic cosmic rays and other chemical species such as ammonia. Here we present the first results from the CLOUD experiment at CERN. We find that atmospherically relevant ammonia mixing ratios of 100 parts per trillion by volume, or less, increase the nucleation rate of sulphuric acid particles more than 100–1,000-fold. Time-resolved molecular measurements reveal that nucleation proceeds by a base-stabilization mechanism involving the stepwise accretion of ammonia molecules. Ions increase the nucleation rate by an additional factor of between two and more than ten at ground-level galactic-cosmic-ray intensities, provided that the nucleation rate lies below the limiting ion-pair production rate. We find that ion-induced binary nucleation of H2SO4–H2O can occur in the mid-troposphere but is negligible in the boundary layer. However, even with the large enhancements in rate due to ammonia and ions, atmospheric concentrations of ammonia and sulphuric acid are insufficient to account for observed boundary-layer nucleation.