A SEMIEMPIRICAL MODEL FOR PARTICLE DEPOSITION ONTO FACIAL SKIN AND EYES - ROLE OF AIR CURRENTS AND ELECTRIC-FIELDS

A semiempirical model has been developed for deposition velocity of particles on the forehead and eyes. It is based on published results of wind tunnel studies of deposition of 2-32 mum airborne particles onto the forehead and realistically-shaped eyes of a manikin. The effects of electric fields and particle charges were included in the model on a purely theoretical basis. The model was used to calculate the combined effects of air currents and electric fields, and it was found that electric fields and particle charges are major determinants for deposition of particles approximately 1 mum in diameter, and air turbulence likely to occur in ventilated rooms is a major determinant for particles larger than 10 mum. The model predicts that deposition of particles from typical indoor environments will be enhanced for persons exposed to electric fields, irrespective of the direction of the field. For a complete characterization, particle concentration, size distribution, mean air velocity, direction and turbulence intensity, electric fields and particle charge distribution should be known. For investigators of exposure to airborne particles and its relation to the office eye syndrome, the model can be used for identifying those parameters which are key for given conditions, thus simplifying the description of exposure.