Laser Aerosol Mass Spectrometry for the Study of Poly(nuclear) Aromatic Compounds Associated With Ultrafine Atmospheric ParticlesEPA Grant Number: U916153
Title: Laser Aerosol Mass Spectrometry for the Study of Poly(nuclear) Aromatic Compounds Associated With Ultrafine Atmospheric Particles
Investigators: LaFranchi, Brian W.
Institution: University of Vermont
EPA Project Officer: Lee, Sonja
Project Period: January 1, 2003 through January 1, 2006
Project Amount: $77,793
RFA: STAR Graduate Fellowships (2003) Recipients Lists
Research Category: Academic Fellowships , Air Quality and Air Toxics , Fellowship - Atmospheric Sciences
The objective of this research project is to develop an analytical methodology that will allow the direct analysis of organic molecules associated with atmospheric particles. The importance of aerosols in air pollution (global warming, human health) and combustion (soot and soot precursors) has increased dramatically in the past years. The direct impact of fine particles on human health has been underscored by the adoption of the stricter National Ambient Air Quality Standards for Particulate Matter (PM2.5), which address the issue that not all particles are alike and that they might not all have the same health effects. Particle-bound toxins, such as polyaromatic hydrocarbons (PAHs), may exhibit toxicological behavior that is dependent on the particle size and/or core composition and that is fundamentally different from the gaseous fraction of these toxins. Methods that can analyze the organic content of the ultrafine fraction of atmospheric particulates are desperately needed to advance our understanding of, among other things, the mechanisms contributing to the pathogenic activity of these particles.
Aerosol mass spectrometry (AMS) is a new method for the online, real time chemical and physical characterization of individual particles. With very few exceptions, AMS has been used only for inorganic particle analysis. Common ionization mechanisms used in AMS include multiphoton and electron impact ionization. None of these, however, is wholly adequate for the analysis of organic compounds associated with ultrafine particles. The laser-based AMS instrument in our laboratory will use resonant desorption and excitation of the analyte or infrared radiation resonance-enhanced multiphoton ionization to study the fundamental processes of molecular desorption and subsequent optical excitation and ionization produced by laser(s) interaction with the surface of individual ultrafine particles.