The beta distribution - a physically consistent model for human exposure to airborne contaminants

This brief note examines the beta distribution as a statistical model for airborne contaminant concentrations, and in particular as a tool to describe occupational exposures. The beta distribution is bounded on both tails and has the flexibility to accommodate skewed data. This is a requirement for any physically consistent model of concentration data. The method described here admits the maximum possible concentration as an upper bound to improve the statistical description. A comparison with the standard lognormal model is illustrated with a data set of naphthalene exposures.