Validation of an EDP-supported model for assessing inhalation exposure during indoor spraying processes

A deterministic indoor air model (SprayExpo) calculating inhalation exposure to aerosols released during professional liquid spraying processes and containing nonevaporable active components has been validated. The model calculates the concentrations in various healthrelevant particle size fractions. It takes into account turbulent diffusion, droplet evaporation, and gravitational settling. Comparisons were carried out at real workplaces in the fields of antifouling treatment and storedproduct protection. For validation, the exposure concentrations of the active substances used were determined by particle sizesegregated personal sampling with the Respicon and subsequent chemical analysis. SprayExpo was found to be an appropriate model for assessing exposures during indoor spraying processes and currently the best model for large room volumes. The sensitivity analysis confirmed the assumption that besides the substance release rate, the droplet spectrum of the spraying device is the process parameter which decisively influences the exposure.