Objectives for the Study • Find tracer compounds representative of the major SOA precursors from laboratory studies. • Identify tracer compounds found both in the laboratory and field. • Estimate the mass fraction of tracers to the formed SOA • Focus on isoprene, α-pinene, β-caryophyllene, toluene • Determine major sources of SOA in PM 2.5 in RTP, NC, Detroit, MI, and other locations using the tracer compounds. • What fraction of the OC represented by SOC. • Compare biogenic vs. anthropogenic contribution. • Examine seasonal dependencies. • Compare differences in location using the same analysis.
Experimental System for Laboratory Studies Ozone, SO 2 and NO/NO x Analyzers Gas Chromatography - Flame Ionization Detector (GC-FID) Other Sampling Hygrometer SOC Msmt Inlet Manifold Semicontinuous Organic Carbon Measurement NERL Dynamic Photochemical Reaction Simulator Volume = 14.5 m 3 40 L min -1 (τ = 6 h) Scanning Mobility Particle Sizer (SMPS) Filter Sampling Devices for Chamber Aerosol Gas Phase Carbonyl Product Measurements Chemical Composition Mass Measurement Inorganic IC GC-MS Gravimetric Mass Organic SOA Msmt MALDI LC-ESI ESI • Experiments conducted in a dynamic mode to operate at relatively low reactant concentrations and to collect sufficient aerosol for analysis. • Analyze tracer compounds by GC/ITMS and OA and OC by standard methods.