AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Inhalation Exposure Characterization for Spray Products
KATHARINA SCHWARZ, Wolfgang Koch, Fraunhofer ITEM, Germany
Abstract Number: 434 Working Group: Aerosol Exposure
Abstract Risk assessment regarding inhalation exposure for spray products requires information on aerosol emission in health related size ranges. Recently, there is an increasing demand in methods for exposure characterization, which consider the aerosol release under conditions of the actual application process including droplet maturation and shrinkage related to the evaporation of the solvents.
Therefore, a method based on the mass balance analysis of the matured aerosols in the respirable, thoracic and inhalable fraction under intended product use, relevant for the inhalation exposure of the spray user, has been developed. The exposure potential is quantified in terms of release fractions, defined as mass of aerosol generated in the three health-related size classes (respirable, res; thoracic, thor and inhalable, inh), normalized to total mass of liquid spray product released (release fractions, Rres, Rthor, Rinh). The three size fractions determined correspond to the three health-related size classes of airborne particles according to international standards (European standard EN 481 and ACGIH standard). These release fractions can be directly used as input parameters for exposure modelling using well-established models such as ConsExpo.
This method has been successfully applied for various spray products and applications, including biocidal droplet and foam spray applications, personal care products and spray processes in building protection. It provides reliable data on inhalation exposure potential for the different applications with release fractions covering several orders of magnitude. For droplet spraying processes, a simple, rough estimation could be derived for the thoracic release fraction based on well available properties of the formulation and the spraying technology.
In conclusion, the mass balance method takes into account the aerosol release potential under realistic conditions of use, i.e. the conditions relevant for the spray applicant. Thus, this new method contributes to the implementation of recommendations concerning the safety assessment of spray products.