Volatility Distribution of Organic Aerosols using ChemSpot Instrument

PURUSHOTTAM KUMAR, James Hurley, Braden Stump, Athena Xu, Nathan Kreisberg, Nga Lee Ng, Pat Keady, Susanne Hering, Gabriel Isaacman-VanWertz, Virginia Tech

     Abstract Number: 437
     Working Group: Instrumentation and Methods

Abstract
A larger portion (>50%) of atmospheric particulate matter consists of organic aerosols but due to their complex and diverse chemical composition their properties and impacts remain poorly understood. The volatility distribution of these organic aerosols provides information on their chemical composition and transformation pathways in the atmosphere, which is crucial for understanding their sources, transport, and impacts on air quality and climate. Traditional techniques for the volatility-resolved composition of organic aerosol involve measurement using a thermal denuder in conjunction with high-resolution mass spectrometry or a filter-based approach connected to a mass spectrometer. Although these techniques provide detailed valuable volatility-resolved organic aerosol composition data, they are still limited by their complexity and cost. Here we present volatility distributions and chemical composition of organic aerosol using the newly developed “ChemSpot” instrument, in which collected particles are thermally desorbed from an inert surface in controlled steps for chemical analysis using a flame ionization detector coupled with a CO₂ monitor and sulfur detector. Samples were collected under ambient conditions in Blacksburg, VA, and during laboratory biomass burning experiments of forest floor material during the Georgia Wildland-fire Simulation Experiment (G-WISE). We examine here the volatility distributions and oxygen content (i.e., 2D volatility basis) in fresh and aged particles, and compare these results to data from collocated particle mass spectrometers.