A modular modeling system for characterizing impacts of emergency events involving releases of biological agents
S. Isukapalli, P.J. Lioy, S. Tong, W. Li, P.G. Georgopoulos
Environmental and Occupational Health Sciences Institute, UMDNJ - R.W. Johnson Medical School and Rutgers University, Piscataway, NJ
A modular modeling system for source-to-dose-to-effect modeling analysis has been developed and applied to study the impacts of inhalation exposures due to hypothetical atmospheric releases of non-infectious biological agents (with specific focus on releases of anthrax). This approach is based on the MENTOR system (Modeling ENvironment for TOtal Risk), and provides a mechanistically consistent analysis of inhalation exposures for various release scenarios, while allowing to examine specific subpopulations (such as the children and elderly) at the resolution of individual census tracts. The case studies presented here include different hypothetical releases of anthrax (e.g. long duration releases, short duration releases, releases from multiple points, etc., and assess the exposures and doses over a period of several days. A set of hierarchical approaches are used for comparative evaluation of the MENTOR system results. These include differences in (a) the estimation of outdoor concentrations from simple dispersion formulations (uniform versus varying windfields) using CALPUFF, (b) the characterization of demographics, by comparing spatially uniform population distributions versus distributions utilizing census data, (c) constant activitires versus representative activity patterns from the Comprehensive Human Activity Database (CHAD). Results indicate that the estimates of potential impacts are very sensitive with respect to assumptions used; the simplifying assumptions result in substantially higher estimates of exposures and doses compared to estimates from detailed human activity patterns and variable microenvironmental factors. The approach presented here has been implemented in a modular fashion so that improvements in individual modules can be readily made without impacting the other modules. The role of this system in realizing an planning tool for emergency response management as well as the issues associated with facilitating real-time application of this modeling system are discussed.
This work is 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.