AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
A Relaxed-Eddy Accumulation System for Measuring Microbial Emission Fluxes from the Vegetation
YVES BRUNET, Jean-Marc Bonnefond, Didier Garrigou, Frédéric Delmas, Christel Leyronas, Cindy E. Morris, INRA Bordeaux, France
Abstract Number: 349 Working Group: Bioaerosols: Characterization and Environmental Impact
Abstract Evidence has been gathered that a substantial proportion of atmospheric micro-organisms originates from plant canopies. However, only very few field measurements of surface fluxes have been performed so far, so that the emission and deposition rates of biological aerosol particles are still largely unknown. One major reason for the lack of experimental data is that such measurements are difficult: (i) fast-response sensors, as required by the reference eddy-covariance method, do not exist for biological particles, and (ii) the gradient method, where the flux is estimated from the concentration difference between two levels above the surface, is only applicable at “ideal” field sites. One potential alternative is the “relaxed-eddy accumulation” method (REA) that has been developed for scalar species for which no fast concentration measurements can be collected. Here we investigate the possibility of adapting the REA method to the measurement of microbial emission from vegetated surfaces. After a presentation of the underlying principles of REA and its conditions of use in the field, we describe a prototype that has been recently built. The system has been tested over four field campaigns, during which the performances of several particle-sampling sensors have been evaluated (impactors, virtual impactors, filters). The first results are given along with a list of recommendations and issues to be solved.