Abstract

Within the framework of the development of a risk assessment system for new chemical substances, estimation methods concerning exposure of man and environment through air have been investigated. The pathways through which exposure through air takes place in this risk assessment system are exposure of human beings by inhalation and exposure of soils by deposition. Previous research (Noordijk & De Leeuw, 1991) has shown that for new chemical substances the existing Operational Priority Substances (OPS) atmospheric transport model (Van Jaarsveld, 1990) is an appropriate tool for the estimation of atmospheric concentrations and deposition fluxes, if some additional parameter estimation procedures are added. This concerns the estimation of the partitioning between gas phase and aerosol, the wash-out ratio, the dry deposition velocity and the atmospheric reaction rate. This report focusses on the implementation of the reported estimation methods within the risk assessment system, using the OPS-model. For this purpose, a simple table has been constructed reflecting simulated concentrations and deposition fluxes as a function of substance characteristics. In order to obtain information on variance in the results, a sensitivity analysis has been carried out for the main parameters and some source characteristics. Ranges of uncertainty are obtained through this analysis.