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

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 narro

SUBMITTER: Davies JF 

PROVIDER: S-EPMC5947524 | biostudies-literature | 2015 Dec

REPOSITORIES: biostudies-literature