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Approaches to Estimate Consumer Exposure under TSCA

On this page:

Introduction to estimating consumer exposure

Exposure to chemicals in consumer products and materials can be estimated by defining the exposure scenarios of interest. Exposure scenarios are typically organized around uses and contain information on product formulations and product-specific properties, use patterns, physical-chemical properties, human exposure factors, and indoor environmental conditions.

Chemicals in consumer products and materials can be a source of human exposure. They can be released into the environment as a result of their manufacturing, distribution, use, and disposal. Human exposure can occur through inhalation, dermal, or oral pathways either through direct use/contact or indirect proximity. Certain products may be disposed down the drain or otherwise migrate during use into environmental media.

EPA estimates exposure to consumer products and materials through use of available measured data and/or modeling approaches.  Some of these models are available as stand-alone downloadable executables.  

Other models are web-based and available on the Agency's Internet Geographical Exposure Modeling System.

Measured data

Using representative and reliable experimentally-derived data helps reduce uncertainty associated with exposure estimates. The EPA Guidelines for Exposure Assessment includes guidance on collecting and using data for exposure assessments. One of the goals in selecting the approach should include characterizing variability and uncertainty associated with central tendency and high-end exposure estimates. Quality assurance and quality control of measured data and models is an important component of EPA exposure assessments.

Read EPA's Guidelines for Exposure Assessment.

Indoor Exposure Product Testing Protocols, Version 2.0.

Modeling approaches

Consumer Exposure Model (CEM)

What Does CEM Do?

  • Estimates indoor air concentrations, indoor dust concentrations, dermal exposure, and mouthing exposure for a wide variety of consumer products and materials
  • Estimates inhalation, ingestion, and dermal exposures, calculated as single day doses and chronic average daily doses.
  • CEM (2.0) retains six existing models (CEM 1.2) within E-FAST V2.0 (.exe, 32MB) and adds nine additional models.
  • CEM (2.0) was peer reviewed and beta tested. 

Download and Install the CEM zip file which includes executable files CEM Draft version 2.0

CEM user's guide is available -- Consumer Exposure Model Version 2.0 User’s Guide and Appendices.

Additional information, including the hardware and software requirements is available in the CEM 2.0 Questions and Answers.

Multi-chamber Concentration and Exposure Model (MCCEM)

What Does MCCEM Do? 

  • Estimates indoor air concentrations of chemicals released from products or materials in houses, apartments, townhouses, or other residences over time. The data libraries contained in MCCEM are limited to residential settings. However, the model can be used to assess other indoor environments (e.g. schools, offices) if the user can supply the necessary inputs.
  • Estimates inhalation exposures to these chemicals, calculated as single day doses, chronic average daily doses, or lifetime average daily doses. All dose estimates are potential doses; they do not account for absorption into the body.

Download and install the MCCEM zip file which includes self-extracting executables


Additional information, including the hardware and software requirements is available in the MCCEM Questions and Answers.

IECCU- Simulation Program for Estimating Chemical Emissions from Sources and Related Changes to Indoor Environmental Concentrations in Buildings with Conditioned and Unconditioned Zones

What Does IECCU do?

  • Models sources such as emissions from building insulation, appliances, stored supplies located in unconditioned zones (e.g., attics, crawlspaces or basements),
  • Models sources such as emissions from application-phase such as Spray Polyurethane Foam insulation or painting interior walls and furniture with oil-based or latex paint,
  • Models emissions from Semi-Volatile Organic Chemical sources such as vinyl flooring, carpeting, and caulking material, in multiple zone buildings,
  • Models interactions of Semi-Volatile Organic Chemicals with airborne Particulate Matter and settled dust in multiple zone buildings,
  • Models short-term emissions that involve chemically reactive species, and
  • Allows for importing air movements and/or zone temperature data from other models.

IECCU User's Guide and Download


Product/material-specific exposure models:

Wall Paint Exposure Model (WPEM)

What Does WPEM Do?

  • Estimates indoor air concentrations of chemicals released from wall paint over time.
  • Estimates the potential inhalation exposure of consumers and workers to the chemicals emitted from wall paint which is applied using a roller or a brush. 

Download and Install the WPEM self-extracting executable file

Additional information, including the hardware and software requirements is available in the WPEM Questions and Answers. 

Get the Wall Paint Exposure Model (WPEM) Version 3.2 User's Guide

Formaldehyde Indoor Air Model- pressed wood products (FIAM-pwp)

What Does FIAM-pwp Do? 
Estimates indoor air concentrations of formaldehyde emitted from pressed wood products such as drywall in a variety of different indoor environments.
Estimates the potential inhalation exposure of residents who live or work in buildings where such pressed wood products are present.

The FIAM-pwp is available in the Internet Geographical Exposure Modeling System/Chemical Safety Mapper (IGEMS/CSM) IGEMS.

Get FIAM-pwp User’s Guide.


Other EPA applications


Source Ranking Database (SRD) to Evaluate Material Products under TSCA as Potential Sources of Indoor Air Pollution

What Does SRD Do? 

  • Prioritizes potential sources of indoor air based on combinations of hundreds of chemicals used in hundreds of product types (thousands of combinations)
  • Estimates risk-informed rankings by combining screening-level indoor air concentrations and hazard scores for each chemical in a given product or material and for each environment in which the product/material is used 

Download and Install the SRD self-extracting executable file
 

Additional information, including the hardware and software requirements is available in the SRD Questions and Answers

The user's guide, background document and appendices are available below as a PDF files: Source Ranking Database (SRD) User's Guide and Documentation, Vol. 1

Arthur D. Little ADL Polymer Migration Estimation Model (AMEM)

What Does AMEM do?

  • Estimates the fraction of a chemical additive that migrates from polymeric materials to air, water, and solids. There are "default" coefficients for six different polymers: silicone rubber, natural rubber, LDPE (Low Density Polyethylene), HDPE (High Density Polyethylene), polystyrene, and unplasiticized PVC (Polyvinylchloride).
  • The model assumes: the chemical is homogeneously distributed throughout the polymer and is not initially present in the phase external to the polymer, migration of the chemical is not affected by the migration of any other chemical or by the penetration into the polymer of any component of the external phase, migration is isothermal, and Fick's law of diffusion and convective mass transfer theory applies.

Download and install the AMEM zip file which contains self-extracting executables
 

Additional information, including the hardware and software requirements is available in AMEM Questions and Answers 

AMEM user's guide is available.

Terms and conditions of use

  • Permission is granted for individuals to download and use the software on their personal and business computers. Users may not alter, modify, merge, adapt, or prepare derivative works from the software.
  • Professional judgment is needed to determine adequacy and applicability of the models and methods provided in CEM, MCCEM, WPEM, FIAM-pwp, SRD, and AMEM. 

EPA Technical Contacts  

Charles B. Bevington
Office of Pollution Prevention and Toxics 
Risk Assessment Division 
E-mail: bevington.charles@epa.gov

David Tobias
Office of Pollution Prevention and Toxics 
Risk Assessment Division 
E-mail: tobias.david@epa.gov