AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Secondary Organic Aerosol Formation from Acylperoxynitrates (APNs) of Biogenic Aldehydes
TRAN NGUYEN, Kelvin Bates, Matthew Coggon, Xuan Zhang, Zhenfa Zhang, Avram Gold, Jason Surratt, John Crounse, Paul Wennberg, John Seinfeld, California Institute of Technology
Abstract Number: 411 Working Group: Aerosol Chemistry
Abstract Biogenic aldehydes, such as methacrolein and pinonaldehyde, are first generation compounds produced in high yields from the tropospheric oxidation of unsaturated hydrocarbons. Their OH-oxidation under typical ambient conditions generates acylperoxynitrates (APNs). These APNs are efficient precursors to secondary organic aerosol (SOA), although the SOA production mechanism is still unclear. We present new results from chamber studies on the photooxidation of methacrolein, pinonaldehyde, and other structurally-specific aldehydes. Chemical species and SOA are monitored with online techniques such as chemical ionization mass spectrometry, gas-chromatography with flame-ionization detection, and aerosol mass spectrometry. The importance of each previously-proposed mechanism (e.g., via the lactone, dioxoketone, or epoxide intermediates) for SOA formation from APNs will be explored. Mechanistic differences in the OH abstraction vs. addition channels in APN chemistry, and their influence toward the production of SOA intermediates, will be discussed.