(385g) Understanding Droplet Growth Rates of Organic Mixtures

Aerosols have the ability to impact the earth's climate and hydrological cycle because of their potential to activate and become cloud droplets. Understanding the chemical and thermodynamic aerosol properties that control cloud droplet growth is necessary for constraining impacts on the hydrological cycle and uncertainties from the aerosol indirect effect. Quantifying anthropogenic effects are important for predicting CCN concentrations and understanding climate changes due to human influence. In our study, we investigate changes in droplet growth from of biogenic secondary organic aerosol (SOA) modified by the presence of two anthropogenic two types of primary organic aerosol (POA) that are emitted by anthropogenic sources; POA from a flash vaporized mixture of motor-oil and fuel and POA emitted by a diesel engine. The aerosol are sampled from a 12 meter-cubed chamber and an Aerodyne quadrapole aerosol mass spectrometer (Q-AMS) measures changes in aerosol chemical composition and a continuous flow thermal gradient CCN counter measures droplet growth rates. We present the droplet sizes of alpha-pinene SOA, motor-oil fuel and diesel exhaust POA and their subsequent mixtures.