Size-resolved eddy covariance measurements of fine particle vertical fluxes

A method is described for field measurements of size-resolved aerosol vertical fluxes over rural areas. The method is based on a direct eddy covariance method and using an Electrical Low-Pressure Impactor (Outdoor ELPI). The main advantage of this method is to measure simultaneously the aerosol vertical fluxes at several submicron sizes. Due to the low response time of the experimental setup (about 1 s) compared to the turbulent time scales of the particle concentrations, a flux correction was applied and it is based on spectral analysis. As an example of results, the particles fluxes normalized by the concentration were measured over a maize field for atmospheric aerosols that ranged in size from 0.007 to 1.6 μm.