Articles | Volume 15, issue 15
Atmos. Chem. Phys., 15, 8643–8656, 2015

Special issue: BEACHON Rocky Mountain Organic Carbon Study (ROCS) and Rocky...

Atmos. Chem. Phys., 15, 8643–8656, 2015

Research article 06 Aug 2015

Research article | 06 Aug 2015

Contribution from biogenic organic compounds to particle growth during the 2010 BEACHON-ROCS campaign in a Colorado temperate needleleaf forest

L. Zhou1,2, R. Gierens1, A. Sogachev3, D. Mogensen1, J. Ortega4, J. N. Smith4,5, P. C. Harley4, A. J. Prenni6, E. J. T. Levin7, A. Turnipseed4, A. Rusanen1, S. Smolander1,8, A. B. Guenther9, M. Kulmala1, T. Karl10, and M. Boy1 L. Zhou et al.
  • 1Department of Physics, P.O. Box 64, 00014 University of Helsinki, Helsinki, Finland
  • 2Helsinki University Centre of Environment, P.O. Box 65, 00014 University of Helsinki, Helsinki, Finland
  • 3Department of Wind Energy, Technical University of Denmark, Frederiksborgvej 399, P.O. Box 49, Building 118, 4000 Roskilde, Denmark
  • 4National Center for Atmospheric Research, Boulder, Colorado, USA
  • 5Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland
  • 6National Park Service, Air Resources Division, Lakewood, CO, USA
  • 7Department of Atmospheric Science, Colorado State University, Fort Collins, CO, USA
  • 8NOAA/Geophysical Fluid Dynamics Laboratory, Princeton University Cooperative Institute for Climate Science, Princeton, NJ, USA
  • 9Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington, USA
  • 10University of Innsbruck, Institute for Meteorology and Geophysics (IMGI), Innrain 52, 6020 Innsbruck, Austria

Abstract. New particle formation (NPF) is an important atmospheric phenomenon. During an NPF event, particles first form by nucleation and then grow further in size. The growth step is crucial because it controls the number of particles that can become cloud condensation nuclei. Among various physical and chemical processes contributing to particle growth, condensation by organic vapors has been suggested as important. In order to better understand the influence of biogenic emissions on particle growth, we carried out modeling studies of NPF events during the BEACHON-ROCS (Bio–hydro–atmosphere interactions of Energy, Aerosol, Carbon, H2O, Organics & Nitrogen – Rocky Mountain Organic Carbon Study) campaign at Manitou Experimental Forest Observatory in Colorado, USA. The site is representative of the semi-arid western USA. With the latest Criegee intermediate reaction rates implemented in the chemistry scheme, the model underestimates sulfuric acid concentration by 50 %, suggesting either missing sources of atmospheric sulfuric acid or an overestimated sink term. The results emphasize the contribution from biogenic volatile organic compound emissions to particle growth by demonstrating the effects of the oxidation products of monoterpenes and 2-Methyl-3-buten-2-ol (MBO). Monoterpene oxidation products are shown to influence the nighttime particle loadings significantly, while their concentrations are insufficient to grow the particles during the day. The growth of ultrafine particles in the daytime appears to be closely related to the OH oxidation products of MBO.

Final-revised paper