ARB Research Seminar

This page updated June 19, 2013

The California Population Indoor Exposure Model, Version 2 (CPIEM 2.0): a User Friendly Assessment Tool for Population Exposure to Air Pollutants

Arlene Rosenbaum, Director, Air Toxics Program, ICF Consulting, San Francisco, California

November 20, 2002
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA

Research Project


This presentation will report on and demonstrate a new version of the California Population Indoor Exposure Model (CPIEM version 2.0). CPIEM2.0 has new calculation capabilities, including uncertainty analysis, as well as greatly improved ease of use through a Windows interface, superior graphic outputs, and an updated database. The CPIEM is a software tool that combines air pollutant concentration distributions for several microenvironments, including outdoors, and population activity patterns that specify time spent in each microenvironment in a Monte Carlo framework to predict distributions of exposure concentrations for the California population. The default databases of microenvironment concentration distributions and activity patterns are specific to California, but the model allows the user to easily add his or her own data as well.

For many air pollutants, the indoor concentration data are either sparse or nonexistent. To address this limitation and to provide a means of evaluating hypothetical exposure reduction activities, the CPIEM also includes a mass-balance algorithm so that the user can estimate indoor concentration distributions based on distributional information for parameters such as indoor source emission rates, building volumes, and air exchange rates.

A new supplementary software program, designed to be used in conjunction with the new CPIEM, facilitates the estimation of the uncertainty of these exposure distributions. The uncertainty supplement creates alternative distributions for the CPIEM input variables with Monte Carlo sampling to reflect our uncertainty about the parameters of the input distributions. The default databases have been updated with more recent data on indoor and outdoor pollutant concentrations, mass-balance parameters, and the demographic composition of California's population.

Other enhancements to the CPIEM capabilities include refinement of the pollutant removal process calculation in the mass-balance algorithm, and additional output metrics.

Speaker Biography

Arlene S. Rosenbaum, Vice-President and Director of the Air Toxics Program at Systems Applications International Division of ICF Consulting, has more than 20 years of experience in environmental analysis. Her fields of expertise are population exposure to air pollutants, air toxics database development, and technical assessment in support of environmental justice evaluations. She has managed projects to develop air dispersion modeling and population exposure assessment methods for air toxics, ozone, and sulfur dioxide, to formulate simulation models that incorporate those methods, and to apply those methods at urban and national levels.

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