Optical Properties of Submicron and Coarse Mode Ambient Particulate Matter in Northern California

Abstract:

Measurements of particulate light absorption, light scattering and light extinction were made at visible wavelengths during the CARES 2010 field study in northern California. Measurements were made for PM1 and PM10 separately, and the difference between these were used to characterize the properties of the supermicron (coarse mode) particles. Additionally, measurements of PM2.5 were used to characterize the hygroscopicity and volatility of the particles and how this depended upon the distribution between submicron and coarse mode particles. Correlations between intensive particle properties, such as the mass scattering and absorption coefficient, and mean particle size are examined to establish the relationships between particle composition within the coarse mode and the resulting particle optical properties.