Jump to main content
Jump to site search

Issue 12, 2015
Previous Article Next Article

Nanoscale interfacial gradients formed by the reactive uptake of OH radicals onto viscous aerosol surfaces

Author affiliations

Abstract

A key but poorly understood chemical process is how gas phase uptake is governed by the relative mobility of molecules at an interface of an atmospheric aerosol. Citric acid (CA), a model system for oxygenated organic aerosol, is used to examine how changes in viscosity, due to changing water content, govern the reactive uptake of gas phase hydroxyl radicals (OH). By comparing the reaction kinetics measured when probing the outer aerosol surface layers with measurements of the bulk particle composition, the effective OH reaction probability is observed to be a complex and non-linear function of the relative humidity (RH). At RH < 50%, the reactive decay of CA is controlled by the viscosity of the particle, where the depletion of CA and the formation of reaction products occurs over a narrow region near the aerosol interface, on the order of 8 nm at 20% RH. At RH = 50% the reaction zone increases to the particle dimensions (i.e. ∼50 nm) and at RH > 50%, the aerosol becomes aqueous and well-mixed on the timescale of the heterogeneous reaction. These results imply that in the atmosphere, the formation and dissipation of interfacial chemical gradients could be significant in viscous and semisolid aerosol and play important roles altering gas-particle partitioning and aging mechanisms (i.e. bulk vs. interface).

Graphical abstract: Nanoscale interfacial gradients formed by the reactive uptake of OH radicals onto viscous aerosol surfaces

Back to tab navigation

Supplementary files

Publication details

The article was received on 26 Jun 2015, accepted on 05 Sep 2015 and first published on 08 Sep 2015


Article type: Edge Article
DOI: 10.1039/C5SC02326B
Author version
available:
Download author version (PDF)
Citation: Chem. Sci., 2015,6, 7020-7027
  • Open access: Creative Commons BY license
  •   Request permissions

    Nanoscale interfacial gradients formed by the reactive uptake of OH radicals onto viscous aerosol surfaces

    J. F. Davies and K. R. Wilson, Chem. Sci., 2015, 6, 7020
    DOI: 10.1039/C5SC02326B

    This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements