1. Aerosol Formation from Biogenic VOCs Paul J. Ziemann Air Pollution Research Center and Department of Environmental Sciences University of California, Riverside

2. Secondary Aerosol Formation Particle Diameter (  m) 0.01 0.3 2 10 Concentration

3. T hermal D esorption P article B eam M ass S pectrometer ( TDPBMS ) and Associated Experimental Apparatus Diffusion Drier Energy Analyzer

4. Numerical Simulation of the Formation of Particle Beams with Aerodynamic Lenses

5. Mechanism of 1-Tetradecene + O 3 Reaction in the Presence of Alcohol, Carboxylic Acid, or Water CH 3 (CH 2 ) 11 CH=CH 2  + O 3  CH 3 (CH 2 ) 11 CH-CH 2.. CH 3 (CH 2 ) 11 CHOO H-OG CH 3 (CH 2 ) 11 CHOOH N 2,O 2 OG OG.. [CHOO]* + CH 3 (CH 2 ) 11 CHO.. [CH 3 (CH 2 ) 11 CHOO]*+ HCHO HCHO CH 3 (CH 2 ) 11 CHO CH 3 (CH 2 ) 11 CHOOCH 2 I I OG OH CH 3 (CH 2 ) 11 CHOOCH(CH 2 ) 11 CH 3 I I OG OH Peroxyhemiacetals Hydroperoxides O OO I

6. TPTD Mass Thermograms from the Reaction of 1-Tetradecene + O 3 in the Presence of Methanol 020406080 0 10 20 30 40 m/z 213 020406080 0 4 8 12 16 m/z 213 0.5 hours 4 hours Temperature ( o C) 020406080 0 1 2 3 m/z 215 4 hours m/z Signal (cps x 10 4 )

7. TPTD: Environmental Chamber Aerosol Mass Spectra

8. Aerosol Component Mass Spectra from the Reaction of 1-Tetradecene + O 3 in the Presence of Methanol

9. TDPBMS: Vapor Pressure Calibration Curve

10. Real-time Mass Spectra of Aerosol from Cyclohexene + O 3 (+ Cyclohexane + H 2 0) Reaction

11. TPTD Thermograms of Cyclohexene + O 3 Aerosol

12. TPTD Mass Spectral Identification of Compounds in Cyclohexene + O 3 Aerosol HO(O)C(CH 2 ) 3 C(O)OH

13. TPTD Mass Spectral Identification of Compounds in Cyclohexene + O 3 Aerosol HO(O)C(CH 2 ) 4 C(O)OH

14. Mass Spectra of Low-Volatility Aerosol from Cyclohexene + O 3 Reaction

15. Summary Chamber studies of cyclohexene + O 3 with TDPBMS analysis identify glutaric acid as the most volatile major aerosol component Dicarboxylic acids (glutaric and adipic) may be formed by intermolecular or intramolecular peroxyacid + aldehyde reaction, followed by decomposition Peroxyhemiacetals formed from peroxyacid + aldehyde reaction may be major low-volatility aerosol components involved in nucleation and/or initial particle growth Future studies need to: Confirm presence of peroxyhemiacetals Determine extent of gas vs. particle reaction Investigate other cyclic alkenes

16. l Dr. Herbert Tobias l Ken Docherty (ETOX) l Derek Beving (ETOX) l Sulekha Chattopadhyay (ES) l Peter Kooiman (Chemistry) l US Environmental Protection Agency l National Science Foundation l US Department of Energy l California Air Resources Board l UC TSR&TP Acknowledgements FUNDING STUDENTS l Professor Roger Atkinson l Professor Janet Arey l Professor Kimberly Prather FACULTY