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Title: Causes and importance of new particle formation in the present-day and preindustrial atmospheres

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 presentmore » day, although we caution that the ion-induced fraction of NPF involving BVOCs is poorly measured at present. In conclusion, 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.« less
ORCiD logo [1] ;  [2] ;  [3] ; ORCiD logo [4] ;  [5] ; ORCiD logo [6] ;  [7] ; ORCiD logo [3] ; ORCiD logo [8] ; ORCiD logo [9] ; ORCiD logo [10] ;  [11] ; ORCiD logo [12] ;  [3] ;  [3] ; ORCiD logo [13] ; ORCiD logo [14] ;  [4] ; ORCiD logo [6] ;  [15] more »;  [16] ;  [3] ; ORCiD logo [4] ;  [16] ; ORCiD logo [3] ;  [17] ; ORCiD logo [4] ;  [18] ;  [4] ;  [19] ;  [4] ; ORCiD logo [1] « less
  1. Univ. of Leeds, Leeds (United Kingdom)
  2. European Organization for Nuclear Research (CERN), Geneva (Switzerland); Goethe Univ. Frankfurt, Frankfurt (Germany)
  3. Paul Scherrer Inst. (PSI), Villigen (Switzerland)
  4. Univ. of Helsinki, Helsinki (Finland)
  5. Harvard Univ., Cambridge, MA (United States)
  6. Goethe Univ. Frankfurt, Frankfurt (Germany)
  7. European Organization for Nuclear Research (CERN), Geneva (Switzerland)
  8. Carnegie Mellon Univ., Pittsburgh, PA (United States)
  9. Finnish Meteorological Institute, Kuopio (Finland)
  10. Helsinki Institute of Physics, Helsinki (Finland)
  11. Goethe Univ. Frankfurt, Frankfurt (Germany); Max Planck Institute for Chemistry, Mainz (Germany)
  12. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  13. Univ. of Innsbruck, Innsbruck (Austria)
  14. Paul Scherrer Inst. (PSI), Villigen (Switzerland); SLFWSL Institute for Snow and Avalanche Research, Davos (Switzerland)
  15. Paul Scherrer Inst. (PSI), Villigen (Switzerland); Univ. of Helsinki, Helsinki (Finland)
  16. Lebedev Physical Institute, Moscow (Russia)
  17. Leibniz Institute for Tropospheric Research, Leipzig (Germany)
  18. Univ. of Colorado, Boulder, CO (United States); National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States)
  19. Univ. of Vienna, Vienna (Austria)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Geophysical Research: Atmospheres
Additional Journal Information:
Journal Volume: 122; Journal Issue: 16; Journal ID: ISSN 2169-897X
American Geophysical Union
Research Org:
Univ. of California, Irvine, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
54 ENVIRONMENTAL SCIENCES; nucleation; aerosol; atmosphere
OSTI Identifier: