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Parameterization of Thermal Properties of Aging Secondary Organic Aerosol Produced by Photo-Oxidation of Selected Terpene Mixtures

Emanuelsson, Eva U.; Mentel, T. F.; Watne, Ågot; Spindler, C.; Bohn, B.; Brauers, T.; Dorn, H. P.; Hallquist, Åsa M.; Haseler, R. and Kiendler-Scharr, A., et al. (2014) In Environmental Science & Technology 48(11). p.6168-6176
Abstract
Formation and evolution of secondary organic aerosols (SOA) from biogenic VOCs influences the Earth's radiative balance. We have examined the photo-oxidation and aging of boreal terpene mixtures in the SAPHIR simulation chamber. Changes in thermal properties and chemical composition, deduced from mass spectrometric measurements, were providing information on the aging of biogenic SOA produced under ambient solar conditions. Effects of precursor mixture, concentration, and photochemical oxidation levels (OH exposure) were evaluated. OH exposure was found to be the major driver in the long term photochemical transformations, i.e., reaction times of several hours up to days, of SOA and its thermal properties, whereas the initial... (More)
Formation and evolution of secondary organic aerosols (SOA) from biogenic VOCs influences the Earth's radiative balance. We have examined the photo-oxidation and aging of boreal terpene mixtures in the SAPHIR simulation chamber. Changes in thermal properties and chemical composition, deduced from mass spectrometric measurements, were providing information on the aging of biogenic SOA produced under ambient solar conditions. Effects of precursor mixture, concentration, and photochemical oxidation levels (OH exposure) were evaluated. OH exposure was found to be the major driver in the long term photochemical transformations, i.e., reaction times of several hours up to days, of SOA and its thermal properties, whereas the initial concentrations and terpenoid mixtures had only minor influence. The volatility distributions were parametrized using a sigmoidal function to determine T-VFR0.5 (the temperature yielding a 50% particle volume fraction remaining) and the steepness of the volatility distribution. T-VFR0.5 increased by 0.3 +/- 0.1% (ca. 1 K), while the steepness increased by 0.9 +/- 0.3% per hour of 1 x 10(6) cm(-3) OH exposure. Thus, aging reduces volatility and increases homogeneity of the vapor pressure distribution, presumably because highly volatile fractions become increasingly susceptible to gas phase oxidation, while less volatile fractions are less reactive with gas phase OH. (Less)
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publication status
published
subject
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Environmental Science & Technology
volume
48
issue
11
pages
6168 - 6176
publisher
The American Chemical Society
external identifiers
  • Scopus:84901918325
ISSN
1520-5851
DOI
10.1021/es405412p
project
MERGE
language
English
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no
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dcd2a4f1-87d3-4ab8-800f-90b68b984e11 (old id 7515496)
date added to LUP
2015-07-08 14:48:52
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2017-01-29 04:18:00
@article{dcd2a4f1-87d3-4ab8-800f-90b68b984e11,
  abstract     = {Formation and evolution of secondary organic aerosols (SOA) from biogenic VOCs influences the Earth's radiative balance. We have examined the photo-oxidation and aging of boreal terpene mixtures in the SAPHIR simulation chamber. Changes in thermal properties and chemical composition, deduced from mass spectrometric measurements, were providing information on the aging of biogenic SOA produced under ambient solar conditions. Effects of precursor mixture, concentration, and photochemical oxidation levels (OH exposure) were evaluated. OH exposure was found to be the major driver in the long term photochemical transformations, i.e., reaction times of several hours up to days, of SOA and its thermal properties, whereas the initial concentrations and terpenoid mixtures had only minor influence. The volatility distributions were parametrized using a sigmoidal function to determine T-VFR0.5 (the temperature yielding a 50% particle volume fraction remaining) and the steepness of the volatility distribution. T-VFR0.5 increased by 0.3 +/- 0.1% (ca. 1 K), while the steepness increased by 0.9 +/- 0.3% per hour of 1 x 10(6) cm(-3) OH exposure. Thus, aging reduces volatility and increases homogeneity of the vapor pressure distribution, presumably because highly volatile fractions become increasingly susceptible to gas phase oxidation, while less volatile fractions are less reactive with gas phase OH.},
  author       = {Emanuelsson, Eva U. and Mentel, T. F. and Watne, Ågot and Spindler, C. and Bohn, B. and Brauers, T. and Dorn, H. P. and Hallquist, Åsa M. and Haseler, R. and Kiendler-Scharr, A. and Muller, K. P. and Pleijel, Håkan and Rohrer, F. and Rubach, F. and Schlosser, E. and Tillmann, R. and Hallquist, Mattias},
  issn         = {1520-5851},
  language     = {eng},
  number       = {11},
  pages        = {6168--6176},
  publisher    = {The American Chemical Society},
  series       = {Environmental Science & Technology},
  title        = {Parameterization of Thermal Properties of Aging Secondary Organic Aerosol Produced by Photo-Oxidation of Selected Terpene Mixtures},
  url          = {http://dx.doi.org/10.1021/es405412p},
  volume       = {48},
  year         = {2014},
}