Presentations and Publications

Pathak, Ravi K., Stanier, C.O., Donahue, N.M., and Pandis, S.N.  “Ozonolysis of α-pinene at atmospherically relevant concentrations: Temperature dependence of aerosol mass fractions (yields)”, 2007, J. Geophys. Res., 112, D03201, doi:10.1029/2006JD007436.

Despite a number of smog chamber studies of the a-pinene/O3 system, the effect of temperature on a-pinene secondary organic aerosol (SOA) mass fractions (or yields) remains poorly understood. In this study, the temperature dependence of secondary organic aerosol mass fractions (AMF) during ozonolysis of a-pinene is investigated in a temperature controlled smog chamber. Experiments were performed with and without ammonium sulfate aerosol seeds at RH<10% and at 0 C, 15 C, 20 C, 30 C and 40 C. The initial α -pinene concentration varied from 3.5 to 50 ppb and an excess of ozone was used. High time resolution secondary organic AMFs were obtained combining continuous gas-phase concentration measurements (using Proton Transfer Reaction Mass Spectrometry, PTR-MS) with continuous aerosol concentration measurements (using a Scanning Mobility Particle Sizer, SMPS) . The presence of inert aerosol seeds is often necessary to minimize experimental errors due to loss of semivolatile vapors to the wall of the chamber. The a-pinene secondary organic AMFs show a weak dependence on temperature in the 15 C to 40 C range and stronger temperature dependence in the 0 C and 15 C range.