Tuesday, September 23, 2014
Molecular characterization of atmospheric organic matter in biogenic secondary organic aerosol, ambient aerosol and clouds
Ms Yunzhu Zhao
(Advisor: Dr. Lynn Mazzoleni)
Department of Chemistry
Michigan Technological University
Atmospheric aerosol affects the Earth’s energy budget, reduces visibility and influences human health. The organic composition of aerosol is quite complex and continuously evolves through various atmospheric processes. To gain a deeper understanding of the molecular composition of atmospheric organic matter (AOM), chamber-generated biogenic secondary organic aerosol (SOA), ambient aerosol and cloud water samples were studied. Ultrahigh resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry was used to provide detailed molecular characterization of the atmospheric samples. Due to the extremely high mass resolution and mass accuracy, thousands of individual molecular formulas were identified in all of the samples studied. Multivariate statistical analysis methods were evaluated to compare the similarities and differences of the sample compositions. The molecular characterization of biogenic SOA, ambient aerosol and clouds will be discussed. This study of the three types of atmospheric samples helps to understand the composition of AOM with respect to atmospheric processes.