IIOAC is a tool based on EPA’s AERMOD for use in assessing releases to air and exposure potential for new and existing chemicals. A key feature of the tool is the grouping of inputs to define emission scenarios. An emission scenario is a collection of releases featuring one or multiple source types, each with different temporal patterns and emission rates. For each emission scenario, the tool provides outputs such as air concentrations, particle deposition, and human exposure doses for receptors at different distances for each source type.
IIOAC allows the user to choose different source types (point/stack, fugitive, area), meteorological stations and local land cover, release durations, particle/vapor scenarios, and urban or rural settings. Modeling defaults are described in the IIOAC User Guide. For example, there are 14 meteorological stations with pre-processed meteorology data. Releases may occur through facility (stack, incinerator, and fugitive), area soil, and area water sources. Daily-averaged and annual-averaged air concentrations are used to estimate chemical exposure doses. IIOAC was developed to process multiple scenarios from multiple sources at once; the tool allows for intermittent releases and variation in meteorological conditions to account for potential variability in exposure conditions.
OPPT designed the Integrated Indoor-Outdoor Air Calculator (IIOAC) as a user-friendly Excel-based tool to estimate indoor and outdoor air concentrations and particle deposition at different distances from sources that release chemical substances to the air. IIOAC allows OPPT to quickly estimate air concentrations from multiple sources and multiple air releases. The tool uses pre-run results from a suite of AERMOD dispersion scenarios run in a variety of meteorological and land-use settings.