Organic Nitrogen in Fresh and Aged Aerosols Produced by Biomass Burning

Jeffrey L. Collett, Jr. (1), Yury Desyaterik (1), Amy Sullivan (1), Chris Hennigan (2), Allen L. Robinson (2), Amanda S. Holden (1), Sonia M. Kreidenweis (1), Bret Schichtel (3)

(1) Colorado State University, Department of Atmospheric Science, Fort Collins (2) Center for Atmospheric Particle Studies,Carnegie Mellon University, Pittsburgh (3) National Park Service/CIRA, Colorado State University, Fort Collins

     Abstract Number: 686
     Last modified: May 14, 2010

Abstract
The atmospheric transport of fixed nitrogen (N) is a critical component of the global N cycle. It has been shown that organic N is an important contributor to atmospheric N, but its sources and composition are largely unknown. In an effort to better understand the sources of organic nitrogen we analyzed fresh and aged smokes from the combustion of wildland fuels that are burned annually in the western and southeastern US. The smoke aging was achieved by photooxidation in a smog chamber. In order to initiate photochemistry, the chamber was irradiated with UV light. Filter collected aerosol samples were extracted with DI water, and analyzed with Time-of-Flight Electrospray Ionization Mass Spectrometry. Analysis has shown that major organic nitrogen compounds in fresh smoke include imidazoles, pyridines, and diethylamine. A possible formation mechanism will be discussed. Fuel extract analysis did not find these species in the original material. UV-Vis spectra indicate that some of the organic nitrogen compounds contribute to the light-absorbing aerosols in the atmosphere. Mass spectra of secondary organic aerosol formed in the aging experiments include important contributions from organic nitrates (nitrophenol, nitrocresol, nitrocatechol, and nitroguaiacol) and aromatic acids (benzoic acid, mono and di-hydroxybenzoic acid). Both the nitrates and acids are most likely formed due to the oxidation of the lignin decomposition products (guaiacol and syringol derivatives) by reaction with OH and NO2.