Estimation of Inhalation Exposure on the Basis of Airborne Nanomaterial Release Data and Propagation Modeling

The lack of data for inhalation exposure concerning the handling of nanostructured materials is limiting the current nanomaterial risk assessment. However, there are numerous studies dealing with the origin of exposure, i.e., the release. The link between release and exposure are transport and transformation phenomena. Thus, propagation modeling was used to simulate transport from source to breathing zone in order to estimate quantitative exposure levels from measured release data for selected scenarios. On the basis of three ventilation and five release scenarios, exposure levels were calculated with and without human thermal plumes for both the nearfield and the farfield. Results show that the often neglected human-induced convective airflow can have a strong impact on the level of exposure, especially for natural ventilation or non-well-designed technical ventilation systems as typical for nonindustrial consumers or handicraft businesses.