Modeling Dermal Exposure—An Illustration for Spray Painting Applications

Abstract

This article presents a conceptual, mathematical model of dermal exposure resulting from aerosol deposition on human forearm hair. The model is applicable to exposure scenarios where dermal deposition is governed by aerosol impaction, interception, and diffusion mechanisms. The model employs filtration theory, single fiber efficiency equations, and a modified potential airflow approximation. The results are extended, using previously published results, for application to dermal deposition on the forearm during spray painting. The average (N = 8) predicted dermal deposition of 1,6-hexamethylene diisocyanate as collected on a 10-cm ² tape strip is 108.9 (± 70.3) pmol, whereas field measurements indicated an average of 168.6 (± 82.0) pmol per strip. The corresponding measured average dermal flux was 3.63 pg/cm ² s (± 1.34); the prediction was 2.24 pg/cm ² sec (± 1.25). The study calls attention to the importance of body hair both for modeling and measuring dermal exposures.

Keywords:

• aerosols
• dermal exposure
• impaction
• isocyanates
• mathematical modeling

ACKNOWLDEGMENTS

We thank the workers of the autobody shop for their willingness to participate in this study.

This work was supported by a grant (R01–OH07598) from the National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of NIOSH.