Real-Time Aerosol Density Determination Utilizing a Modified Scanning Mobility Particle Sizer-Aerosol Particle Mass Analyzer System

Real time secondary organic aerosol (SOA) density evolution for m-xylene photo-oxidation and α-pinene ozonolysis was obtained using an Aerosol Particle Mass Analyzer (APM)/Scanning Mobility Particle Spectrometer (SMPS) setup, which has been modified to achieve higher transmission of particles and improved sampling frequency. The aerosol density of SOA generated from α-pinene ozonolysis was found to be 1.24 ± 0.03 g/cm 3 while the aerosol generated from m-xylene photo-oxidation was determined to be 1.35 ± 0.03 g/cm 3 . These results confirm the measurement approach from a combined SMPS and Aerodyne Aerosol Mass Spectrometer (AMS) system and are found to be within good agreement with the effective density measurements.