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Aerosol Formation from Biogenic VOCs

Aerosol Formation from Biogenic VOCs. Paul J. Ziemann Air Pollution Research Center and Department of Environmental Sciences University of California, Riverside. Secondary Aerosol Formation. Concentration. 0.01 0.3 2 10. Particle Diameter ( m m).

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Aerosol Formation from Biogenic VOCs

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  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 Concentration 0.01 0.3 2 10 Particle Diameter (mm)

  3. Thermal Desorption Particle Beam Mass Spectrometer (TDPBMS) and Associated Experimental Apparatus Diffusion Drier Energy Analyzer

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

  5. Mechanism of 1-Tetradecene + O3 Reaction in the Presence of Alcohol, Carboxylic Acid, or Water . . [CHOO]* + CH3(CH2)11CHO O O O • CH3(CH2)11CH=CH2 • + O3 CH3(CH2)11CH-CH2 . . [CH3(CH2)11CHOO]*+HCHO • N2,O2 • . . • CH3(CH2)11CHOO CH3(CH2)11CHOOCH2 I I OG OH • H-OG HCHO • CH3(CH2)11CHOOH I CH3(CH2)11CHOOCH(CH2)11CH3 I I OG OH Hydroperoxides • OG CH3(CH2)11CHO Peroxyhemiacetals

  6. TPTD Mass Thermograms from the Reaction of 1-Tetradecene + O3 in the Presence of Methanol 40 0.5 hours 30 20 m/z 213 10 0 0 20 40 60 80 16 4 hours 12 8 m/z Signal (cps x 104) m/z 213 4 0 0 20 40 60 80 3 4 hours 2 m/z 215 1 0 0 20 40 60 80 o Temperature ( C)

  7. TPTD: Environmental Chamber Aerosol Mass Spectra

  8. Aerosol Component Mass Spectra from the Reaction of 1-Tetradecene + O3 in the Presence of Methanol

  9. TDPBMS: Vapor Pressure Calibration Curve

  10. Real-time Mass Spectra of Aerosol from Cyclohexene + O3 (+ Cyclohexane + H20) Reaction

  11. TPTD Thermograms of Cyclohexene + O3 Aerosol

  12. TPTD Mass Spectral Identification of Compounds in Cyclohexene + O3 Aerosol HO(O)C(CH2)3C(O)OH

  13. TPTD Mass Spectral Identification of Compounds in Cyclohexene + O3 Aerosol HO(O)C(CH2)4C(O)OH

  14. Mass Spectra of Low-Volatility Aerosol from Cyclohexene + O3 Reaction

  15. Summary • Chamber studies of cyclohexene + O3 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. Acknowledgements FACULTY STUDENTS • Professor Roger Atkinson • Professor Janet Arey • Professor Kimberly Prather • Dr. Herbert Tobias • Ken Docherty (ETOX) • Derek Beving (ETOX) • Sulekha Chattopadhyay (ES) • Peter Kooiman (Chemistry) FUNDING • US Environmental Protection Agency • National Science Foundation • US Department of Energy • California Air Resources Board • UC TSR&TP

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