1. 1 Huff Hartz Research Group What are aerosol yields from a precursor mixture that reflects the complexity of atmospheric emissions? Do the aerosol yields in smog chamber experiments mimic those found in the atmosphere? What are the oxidation products of biogenic precursor mixtures? Our approach: essential oils

2. 2 SIUC Environmental Chamber 5 m 3 Teflon Chamber Air Filtration System Ozone Monitor Scanning Mobility Particle Sizer Injection Port Ozone Generator Filter Samples Ion trap GCMS Solid-Phase Microextraction Headspace SPME  -pinene SOA extract blank IS

3. 3 SOA from Siberian Fir Needle Oil M o,  g/m 3 bornyl acetate780 camphene523  -pinene 280 3-carene210 limonene105 terpinolene26  -terpineol 6  -pinene 18 borneol20 sesquiterpenes<20 Total M o,  g/m 3 665 SOA Mass,  g/m 3 282 If we apply the two- component model of Presto et al.: Yield = 0.32 Yield = 0.42 bornyl acetatecamphene 3-carene  -pinene limoneneterpinolene  -terpineol  -pinene borneol Time, min. Total Ion Count  -pinene camphene  -pinene 3-carene limonene terpinolene borneol  -terpineol bornyl acetate  -caryophyllene humulene C 15 H 24 borneol