Atmos. Chem. Phys. Discuss., 13, 9319-9354, 2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Dependence of particle nucleation and growth on high molecular weight gas phase products during ozonolysis of α-pinene
J. Zhao1,2, J. Ortega2, M. Chen1, P. H. McMurry1, and J. N. Smith2,3
1Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA
2Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, Colorado 80307, USA
3Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland

Abstract. We report the first time-dependent measurements of high molecular weight (up to 700 amu) gas-phase oxidation products from α-pinene ozonolysis in an aerosol chamber under dry and low NOx conditions. Measurements of products having mole fractions ranging from 10−14 to −11 were carried out with a chemical ionization mass spectrometer (the Cluster CIMS). Most products that were correlated with number concentrations of the smallest particles measured (10–20 nm) had molecular weights in the 430–560 amu range. Those products are proposed to be likely responsible for the initial nuclei formation and the early growth of the freshly-nucleated particles based on their high molecular weights and chemical identities, both of which suggest low volatility compounds. Another group of oxidation products in the lower mass range of 140–380 amu was well correlated with particles larger than 20 nm. We postulate that those products contributed to the later growth of particles (i.e. larger than 20 nm in diameter). Although particle nucleation in this study was primarily due to condensation of oxidation products from α-pinene ozonolysis, the involvement of residual sulfuric acid vapor in particle nucleation cannot be totally excluded.

Citation: Zhao, J., Ortega, J., Chen, M., McMurry, P. H., and Smith, J. N.: Dependence of particle nucleation and growth on high molecular weight gas phase products during ozonolysis of α-pinene, Atmos. Chem. Phys. Discuss., 13, 9319-9354, doi:10.5194/acpd-13-9319-2013, 2013.
Search ACPD
Discussion Paper
Final Revised Paper