Aerosol formation and growth in atmospheric organic/NO_x systems—I. Outdoor smog chamber studies of C_7- and C_8-hydrocarbons
Abstract
Outdoor smog chamber experiments have been performed to determine the aerosol-forming potential of selected C_7- and C_8-hydrocarbons in sunlight-irradiated hydrocarbon-NO_x mixtures. Measured aerosol size distributions were used to determine the rates of gas-to-particle conversion and to study the effects of the addition of SO_2 and/or NH_3 on aerosol formation and growth. The average aerosol yields by mass for the hydrocarbons studied were (the range of measured values for methylcyclohexane and 1-octene are in parentheses): • methylcyclohexane 9.2% (0.12–18.8); • 1-octene 4.2% (0.17–6.9); • toluene 18.6%; • n-octane <0.001%. The average yields are accompanied by large standard deviations (see Table 3) and depended strongly on the conditions, particularly the hydrocarbon to NO_x initial concentration ratio. Addition of SO_2 to the organic/NO_x systems led to an early nucleation burst and subsequent rapid growth of the newly formed aerosol. In the presence of NH_3, the gas-to-particle conversion rate of the organic/NO_x system was enhanced perhaps due to the formation of NH_4NO_3 or the reaction of NH_3 with carboxylic acids. Sustained particle formation was observed when both SO_2 and NH_3 were present, presumably as a result of (NH_4)_2SO_4 formation. We have estimated the complexity of the 1-octene aerosol and identified 5-propyl furanone as a component of the aerosol.
Additional Information
© 1991 Elsevier. (First received 6 December 1990 and in final form 9 May 1991). This work was supported by the Coordinating Research Council, project AP-6. Assistance in conducting the smog chamber experiments by Fangdong Yin is appreciated. The authors also wish to acknowledge Rudi Karch and Wolfgang Winklmayr from the University of Vienna for their contributions to the aerosol measurements. The authors also wish to thank Christoph Schaffner and Walter Giger of Swiss Federal Institute of Water Resources and Water Pollution Control (EAWAG) in Diibendorf, Switzerland, for carrying out the GC-MS analysis of the aerosol samples.Additional details
- Eprint ID
- 65070
- DOI
- 10.1016/0960-1686(92)90326-G
- Resolver ID
- CaltechAUTHORS:20160303-162819560
- Coordinating Research Council
- AP-6
- Created
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2016-03-04Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field