We note that in the absence of the aerosol, the PAH vapor released by the asphalt is not detected by the aerosol mass spectrometer because if not deposited on a particle, very little of the species enters that region. Quantitative calibration of the data is in progress. Reaction of Oleic Acid Aerosols With Ozone. In this experiment oleic acid was introduced into the flow tube in the presence of ozone. Oleic acid decay curves for several ozone concentrations and particle sizes have been obtained.
Products diffuse from the reaction zone into the core of the particle.
Thus, rapid consumption of ozone depends on relatively fast transport of reactant within the particle, which is the case for liquid droplets. Increases in viscosity may also decrease the uptake rate. Stearic acid is a solid at room temperature, because it is more efficient at packing than the bent-chain oleic acid. We expect that it will increase the viscosity of the liquid particles and reduce the diffusion rate. This surprisingly strong effect is being investigated in detail.