Incorporating inter- and intra-individual variability of physiological parameters used in inhalation dosimetry modeling
P. Shade, Y.C. Yang, P.G. Georgopoulos
Environmental and Occupational Health Sciences Institute, UMDNJ - R.W. Johnson Medical School and Rutgers University
Inhalation dosimetry plays a key role in determining the link between environmental exposure to airborne contaminants and observed human health effects. An essential step in the modeling of particle deposition along the human respiratory tract is the incorporation of appropriate physiological and anatomical parameters. However, there is uncertainty and significant inter- and intra-individual variability associated with these parameters, posing a considerable challenge in the evaluation of exposure/response associations. Traditional approaches have two important limitations; distributions of these parameters are often not utilized, and point estimates and empirical expressions are often used beyond their range of applicability.
This effort focuses on the utilization of existing databases of physiological and anatomical parameters, that account for variation due to age and gender differences, in the calculation of both inhalation rates and corresponding lung depositions and doses. Several sources of data have been incorporated in the Modeling Environment for Total Risk (MENTOR) system and various case studies have been performed with the objective of examining the impact of physiological parameter uncertainty and variability on model outcomes, for different exposure scenarios. The model results generated using this approach are also compared to available standard dosimetry modeling calculations.
This work had been funded in part by the US Environmental Protection Agency under Cooperative Agreement # EPAR-827033 to the Environmental and Occupational Health Sciences Institute (EOHSI). The viewpoints expressed here are the responsibility of the authors and do not necessarily reflect the views of the USEPA or its contractors.