Professor, Analytical spectroscopy & environmental analyses, Chemistry department, U de M
Atmospheric Aerosol Composition and Sources in Los Angeles Studied by In-Situ Mass Spectrometry
Atmospheric aerosols have a well-known impact on human health and climate as highlighted in the most recent Intergovernmental Panel on Climate Change report published in 2013. However, atmospheric aerosols remain poorly characterized because, in part, of their chemical complexity. Specifically, the organic fraction of aerosols is composed of thousands of compounds that have a wide range of sources in the environment (e.g. diesel combustion and cooking emissions). This seminar will describe mass spectrometry measurements of organic aerosols carried out near Los Angeles as part of the CalNex field campaign. Five distinct chemical classes of organic aerosol are identified, and using the measured elemental compositions, mass spectra, and correlations with tracers each class can be associated with specific sources. Important findings include the observation that the total organic aerosol mass concentration is dominated by “secondary” organic aerosols, which are composed of the low volatility oxidation products of gaseous emissions.
Patrick Hayes received his B.A. at Oberlin College in Ohio, and subsequently earned his Ph.D. in chemistry at Northwestern University under the guidance of Professor Franz Geiger. Dr. Hayes’ doctoral research investigated the interactions of adsorbates with geochemical solid/liquid interfaces using nonlinear optics. After completing his doctoral work, Dr. Hayes was a CIRES Postdoctoral Fellow at the University of Colorado with Prof. Jose-Luis Jimenez, and performed field measurements and modeling studies of aerosols in the Los Angeles metropolitan region. Dr. Hayes started as an assistant professor of analytical/environmental chemistry at Université de Montréal in August 2013.