MENTOR-based OPERAS (particle exposure and risk analysis systems): An overview
P.G. Georgopoulos, P.J. Lioy (EOHSI, UMDNJ - R.W. Johnson Medical School and Rutgers University)
Objective of the MENTOR (Modeling Environment for Total Risk studies) Project is to develop, apply, and evaluate state-of-the-art computational tools that support multiscale source-to-dose studies and exposure assessments for a wide range of environmental contaminants. These tools include both (I) environmental and biological process models, and (II) techniques that facilitate the diagnostic analysis and evaluation of both process models and related data. MENTOR is not a single model; it is a framework that includes models, databases, and numerical and analytic tools for probabilistically assessing exposures (and doses) to individuals, populations, and susceptible subpopulations as well as for diagnosing the complex relationships between sources and dose.
MENTOR-based OPERAS (Ozone and Particle Exposure and Risk Analysis Systems) are implementations of complementary mechanistic (emissions-based) AQSMs (Air Quality Simulation Models) and phenomenological AOBMs (Aerometric Observation-Based Models), linked with novel microenvironmental and exposure/dose models, that aim to enhance understanding of exposures and health risk from fine airborne particulate matter (PM) and photochemical pollution. An essential element of the modeling approach in MENTOR-OPERAS is the explicit requirement of maintaining mechanistic compatibility across different spatial and temporal scales (corresponding to regional, urban, local, microenvironmental and physiological processes) by treating the underlying physics and chemistry in a consistent manner (in terms of constitutive relations, dimensionality, lumping approximations, transition matching, etc.). So, in the case of PM, the same fundamental mechanical and chemical/thermodynamic attributes that characterize particle mass and number concentration distributions (e.g. lumped species in particle size-dependent chemical composition, etc.) are maintained (appropriately modified to reflect dominance of relevant processes) in the entire sequence of modeling steps that lead from source (atmospheric and indoor emissions of primary particles and gaseous precursors) to dose (generation-dependent lung deposition). The architecture and alternative component options in MENTOR-OPERAS are presented here, as well as results from selected case studies (Los Angeles and Philadelphia OPERAS).