Obtaining Ambient Organic Aerosol Volatility Using the Filter Inlet for Gas and Aerosol Phase (FIGAERO)

Aerosols are a suspension of solid or liquid particles in a gas. They can influence the climate directly through scattering or absorption of solar radiation, or indirectly through their ability to act as cloud condensation nuclei. Tropospheric aerosols are comprised from an organic as well as inorganic phase with the organic phase being a major constituent. Organic aerosol composition is affected by both chemical and physical atmospheric processes in the gas and particle phase. Gas to particle partitioning is dependent on species volatility. Laboratory chamber studies are not able to provide the full range of experimental conditions necessary to reflect these atmospheric processes. Additionally, previous measurements in both the gas and particle phase have required the use of multiple instruments. The filter inlet for gas and aerosol phase (FIGAERO) is an inlet that allows for the collection and measurement of species in the gas and particle phase. The FIGAERO is coupled to a time-of-flight chemical ionization mass spectrometer (ToF-CIMS), which is optimized for sampling in both lab and field works. The FIGAERO allows for volatility measurements of individual compounds in the particle phase through stepwise thermal desorption. Volatility information from these measurements can be extracted using (1) thermogram analysis (2) volatility basis sets and (3) gas to particle phase partitioning. These three methods using the FIGAERO-CIMS allows for greater accuracy and optimization of volatility measurements of ambient aerosols.