Collection and analysis of inorganic and water soluble organic aerosols over Maryland and Virginia

Aerosols aloft have slower removal than those near the ground, in part, because dry and wet deposition rates result in longer lifetimes and greater range of influence. Knowledge of deposition rates and range of transport for different species are important for developing local and regional air quality policy. Currently, the vertical distribution of organic aerosols (OA's) and their polar, oxidized fraction is largely unknown. Comprehensive methods to analyze aerosol composition collected in the boundary layer and the lower free troposphere are lacking. During DISCOVER AQ 2011, both the NASA P3 and Cessna 402B collected aerosols, through shrouded aerosol inlets, onto Teflon and quartz fiber filters. Collection occurred in both the boundary layer and lower free troposphere over Maryland and Virginia, USA. After extraction with water and optimizing separation via ion chromatography, commonly identified secondary organic aerosols can be separated based on their functionality as mono-, di-, or polycarboxylic acids. Inorganic aerosol components can simultaneously be separated and identified with the same method. Individual organic acid compound analysis with detection limits in the low ppb range can be achieved when conductivity/ultraviolet/ and mass spectrometric detectors are placed in tandem. Additionally, thermo optical analysis can be used to determine the mass fraction of water soluble organic carbon versus the total collected mass. This research is designed to provide information on the vertical distribution of particulate organic carbon in the atmosphere, its optical properties, information on aerosol transport in the lower free troposphere, and to provide water soluble organic aerosol structural characterization.