Abstract View
Variation in Organic Aerosol Volatility Derived from Combined Thermal Desorption and Chemical Composition Measurements in Different Environments across the Globe
CLAUDIA MOHR, Wei Huang, Cheng Wu, Yvette Gramlich, Sophie Haslett, Joel A. Thornton, Felipe Lopez-Hilfiker, Ben H. Lee, Harald Saathoff, Xiaoli Shen, Ramakrishna Ramisetty, Linyu Gao, Junwei Song, Siegfried Schobesberger, Liine Heikkinen, Sara Blichner, Ilona Riipinen, Stockholm University
Abstract Number: 300
Working Group: Aerosol Chemistry
Abstract
The development of the filter inlet for gases and aerosols that can be coupled to a time-of-flight chemical ionization mass spectrometer (FIGAERO-CIMS) has enabled the combined analysis of molecular composition and volatility of organic aerosol particles and their precursor gases in real time (Thornton et al., 2020). With the FIGAERO, volatility of particulate compounds is assessed through the analysis of their signal evolution as a function of temperature (called thermograms) when being desorbed from the filter. In addition, the information on molecular composition of particulate and gaseous compounds from the chemical ionization mass spectrometer can be used in volatility parametrizations (Isaacman-VanWertz et al., 2020) to calculate the compounds’ saturation vapor pressure, and to establish volatility basis sets (VBS, Donahue et al., 2011) for the bulk aerosol. VBS are used in model frameworks from the process to the global scale (e.g. Mohr et al., 2019; Farina et al. 2010), as they allow for an efficient description of organic aerosol partitioning and chemical aging – albeit with large uncertainties, as volatility measurements and estimates are subject to these.
Here we present a comparison of organic aerosol volatility derived from molecular composition measurements and thermogram analysis for a number of ambient FIGAERO-CIMS datasets across the globe (Mt. Chacaltaya, Bolivia; Alabama, US; Hyytiälä, Finland; Stuttgart and Karlsruhe, Germany; Delhi, India). We will assess the variability of derived volatility, discuss the reasons for differences and similarities in the relationships between volatility and chemical composition for the different locations and environments, compare the FIGAERO-based results to other methods for particle volatility determination, and discuss the limitations of parametrizations. In addition, we will show implications of volatility variation in different model frameworks, such as e.g. the use of VBS in a cloud parcel model.
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[4] Mohr et al., Nat. Commun. 2019, 10, 4442.
[5] Farina et al., J. Geophys. Res. 2010, 115, D09202.