Towards direct measurement of turbulent vertical fluxes of compounds in atmospheric aerosol particles

Abstract

Vertical fluxes of gaseous and particulate compounds in the planetary boundary layer are mainly established through turbulence. To date, it is a challenge to measure vertical fluxes of particles and, even more, the fluxes of compounds in particulates. The combination of disjunct eddy sampling and time-of-flight MS single particle analysis bears the potential to directly measure the turbulent particle flux together with the chemical particle composition. Several obstacles must be overcome before this goal may be achieved. In this paper, we present a statistical procedure, using Monte-Carlo-type simulations, to obtain the flux direction of particulate compounds such as nitrate. A first experimental application of this method yielded emission of particulate NO-3 - from a forest ecosystem on a summer day with a statistical confidence of 89%.