Sign up & Download
Sign in

Internal mixing of the organic aerosol by gas phase diffusion of semivolatile organic compounds

by C Marcolli, B Luo, T Peter, F Wienhold
Atmospheric Chemistry and Physics ()

Abstract

This paper shows that most of the so far identified constituents of the tropospheric organic particulate matter belong to a semivolatile fraction for which gas phase diffusion in the lower troposphere is sufficiently fast to establish thermodynamic equilibrium between aerosol particles. For the first time analytical expressions for this process are derived. Inspection of vapor pressure data of a series of organic substances allows a rough estimate for which substances this mixing process must be considered. As general benchmarks we conclude that for typical aerosol radii between 0.1 and 1 mum this mixing process is efficient at 25 degreesC for polar species with molecular weights up to 200 and for non-polar species up to 320. At - 10 degreesC, these values are shifted to 150 for polar and to 270 for non-polar substances. The extent of mixing of this semivolatile fraction is governed by equilibrium thermodynamics, leading to a selectively, though not completely, internally mixed aerosol. The internal mixing leads to a systematic depression of melting and deliquescence points of organic and mixed organic/inorganic aerosols, thus leading to an aerosol population in the lower troposphere which is predominantly liquid.

Cite this document (BETA)

Readership Statistics

1 Reader on Mendeley
by Discipline
 
by Academic Status
 
100% Associate Professor

Tags

Sign up today - FREE

Mendeley saves you time finding and organizing research. Learn more

  • All your research in one place
  • Add and import papers easily
  • Access it anywhere, anytime

Start using Mendeley in seconds!

Already have an account? Sign in