Duration: 2011-2013
Contact: Jay Slowik, jay.slowik@psi.ch
Scope of project
Quantification of aerosol climate and health effects requires a detailed knowledge of aerosol concentrations, chemical and physical properties, and atmospheric lifetimes. However, such quantification has proven extremely challenging, particularly for the organic fraction, because of spatial and temporal variability in the sources of aerosols and their precursor gaes, the complexity of particle composition, and uncertainties regarding the nature and timescales of atmospheric chemical processing of existing particles. Here we decouple source and processing effects through experiments on aerosol formation and aging using model compounds (e.g. glyoxal and alpha-pinene), selected sources (e.g. vehicle and cooking emissions), and ambient particles. Reactive conditions simulating atmospheric oxidation processes are controlled in parallel experiments using a stationary smogchamber, mobile smogchamber, and portable flow reactor. Characterization of the aging process is accomplished by mass spectral analysis, factor analysis-based descriptions such as positive matrix factorization, and optical properties. Combining real-world sources with controlled processing conditions leads to an increased process-level understanding of organic aerosol aging and enhanced interpretation of the results from existing source apportionment techniques.