Theoretical analyses of aerosol aging on a substrate without wall-effects by a cross-flow
Long time ({approx}1 day) aging or reactions of aerosol is typically studied using either large aerosol chambers (> 10 m3) or particles supported on a substrate to minimize wall effects. To avoid wall effects in the latter, it is often essential that the wall reactivity be extremely small (<< 10-5 reactions per encounter) and that the particle loadings be very small (< 1 pg/cm2) to eliminate transport-limited trace gas depletion near the particles and substrate. We evaluate here a cross-flow approach, which greatly reduces these constraints. Particles are to be supported on a micromesh ({approx}50% or more open area) through which the reactive gas is drawn at around a few hundred cm/s. The analysis shows how the competitions between flow and diffusion establishes a 'zone of isolation' several microns wide around each reactive particle, outside of which the reactivity of other particles or the substrate are irrelevant to the local reactions. This cross-flow approach reduces the effects of substrate and collective particle reactivity typically orders of magnitude, and will facilitate aging studies of supported aerosols.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1033454
- Report Number(s):
- PNNL-SA-76494; 17807; 17806; KC0301020; KP1205030; TRN: US201202%%765
- Journal Information:
- Open Atmospheric Science Journal, Vol. 5
- Country of Publication:
- United States
- Language:
- English
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