EUROTRAC-BIATEX. An European program for the investigation of biosphere atmosphere exchange of pollutants

The biosphere (i.e. vegetation, soil and microorganisms) acts both, as a sink and source of tropospheric trace constituents. The biosphere has a significant influence on the chemical composition of the atmosphere on a regional and global scale, and thus on several important areas of environmental problems, e.g. acidity of rain and fog, climate, and troposheric ozone formation. Despite of this importance, our knowledge on exchance rates of the individual trace constituents at the biosphere/atmosphere interface is poor. The same applies for the mechanisms involved, which have to be known in order to understand satisfactorily the fate and effects of these trace constituents. However, for modelling tropospheric chemistry processes and for studying emission-effect relaaltions, a better knowledge of biosphere/atmosphere interactions is essential. To attack these problems 27 European research institutions have joint forces to establish the subproject "Biosphere-Atmosphere Exchange of Pollutan ts (BIATEX) "within the frame of EUROTRAC an environmental project of the EUREKA initiative. The aim of the BIATEX-subproject is the quantification of pollutants fluxes between atmosphere and biosphere; the study of the mechanisms within soils and plants which are responsible for the observed exchange, and the provision of regional fluxes on seasonal and annual scales for Europe. In this paper a brief overview of the state of the art regarding Biosphere-Atmosphere exchange of pollutants will be given, followed by the objectives and the planned activities of the BIATEX-program.