Isoprene oxidation by nitrate radical: alkyl nitrate and secondary organic aerosol yields

Rollins, A. W.; Mensah, A.; Mentel, T. F.; Fuchs, H.; Cohen, R.C.; Brauers, T.; Wegener, R.; Tillmann, R.; Kiendler-Scharr, A.; Wooldridge, P. J.; Brown, S. S.; Dubé, W. P.; Rohrer, F.; Fry, J. L.; Dorn, H.-P.

Journal Article

Isoprene oxidation by nitrate radical: alkyl nitrate and secondary organic aerosol yields

Rollins, A. W. ; Kiendler-Scharr, A.FZJ* ; Fry, J. L. ; Brauers, T.FZJ* ; Brown, S. S. ; Dorn, H.-P.FZJ* ; Dubé, W. P. ; Fuchs, H.FZJ* ; Mensah, A.FZJ* ; Mentel, T. F.FZJ* ; Rohrer, F.FZJ* ; Tillmann, R.FZJ* ; Wegener, R.FZJ* ; Wooldridge, P. J. ; Cohen, R. C.

2009
EGU Katlenburg-Lindau

Atmospheric chemistry and physics 9, 6685 - 6703 (2009)

This record in other databases:

Please use a persistent id in citations: http://hdl.handle.net/2128/10132

Abstract: Alkyl nitrates and secondary organic aerosol (SOA) produced during the oxidation of isoprene by nitrate radicals has been observed in the SAPHIR ( Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) chamber. A 16 h dark experiment was conducted with temperatures at 289-301 K, and maximum concentrations of 11 ppb isoprene, 62.4 ppb O-3 and 31.1 ppb NOX. We find the yield of nitrates is 70 +/- 8% from the isoprene + NO3 reaction, and the yield for secondary dinitrates produced in the reaction of primary isoprene nitrates with NO3 is 40 +/- 20%. We find an effective rate constant for reaction of NO3 with the group of first generation oxidation products to be 7 x 10(-14) molecule(-1) cm(3) s(-1). At the low total organic aerosol concentration in the chamber (max=0.52 mu g m(-3)) we observed a mass yield (Delta SOA mass/Delta isoprene mass) of 2% for the entire 16 h experiment. However a comparison of the timing of the observed SOA production to a box model simulation of first and second generation oxidation products shows that the yield from the first generation products was <0.7% while the further oxidation of the initial products leads to a yield of 14% ( defined as Delta SOA/Delta isoprene(2X) where Delta isoprene(2X) is the mass of isoprene which reacted twice with NO3). The SOA yield of 14% is consistent with equilibrium partitioning of highly functionalized C-5 products of isoprene oxidation.

Keyword(s): J

Classification:

Meteorology & Atmospheric Sciences

Note: The Berkeley authors were supported by NSF ATM-0639847 and NSF ATM-0511829. The authors would like to thank the SAPHIR NO<INF>3</INF> intercomparison campaign team for organizing and administering the experiments in June 2007 at Forschungszentrum Julich. This work was a joint activity of the European Community Network of Excellence ACCENT, grant no. GOCE CT-2004-505337 and the EUROCHAMP project.

Research Program(s):