On this page:

Introduction to estimating consumer exposure
Measured Data
Modeling Approaches

Consumer Exposure Model (CEM)
Multi-chamber Concentration and Exposure Model (MCCEM)

Product/Material Specific Exposure Models

Wall Paint Exposure Model (WPEM)
Formaldehyde Indoor Air Model- pressed wood products (FIAM-pwp)

Other OPPT Applications

Source Ranking Database (SRD)
ADL Polymer Migration Estimation Model (AMEM)

Terms and conditions of use

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.

OPPT 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 OPPT’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 OPPT exposure assessments. The attached Draft Indoor Exposure Testing Guidelines [pdf] were compiled from existing sources and organized in general framework.

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 (1.3) retains six existing models (CEM 1.2) within E-FAST V2.0 (XX MB) and adds nine additional models.
CEM (1.3) is available as a beta test version.  OPPT is scoping a peer review and plans to incorporate beta tester and peer reviewer feedback prior to posting a final version of CEM 1.3.

CEM Beta 1.3 can be downloaded and installed using LINK

The user's guide is available as a pdf file Consumer Exposure Model Version 1.3 User’s Guide PDF File

PLEASE NOTE: You may need a PDF reader to view some of the files on this page. See EPA's About PDF page to learn more.

Additional information, including the hardware and software requirements is available in the CEM 1.3 Questions and Answers [pdf]

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.

Using MCCEM

MCCEM can be downloaded and installed using download MCCEM.

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

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.
 

Using WPEM

The WPEM model can be downloaded and installed using download WPEM.

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

The user's guide is available as a pdf file Wall Paint Exposure Model (WPEM) Version 3.2 User's Guide (PDF)(668KB, 145pp)

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.

Using FIAM-pwp

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

The user's guide is available as a pdf file FIAM-pwp User’s Guide  (PDF)(668KB[FC1] ,

Other OPPT 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

Using SRD

The SRD can be downloaded and installed using download SRD.

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

The user's guide and background document is available below as a pdf file.
Source Ranking Database (SRD) User's Guide and Documentation, Vol. 1 (PDF)(1.9MB, 108pp)

The appendices are available as a pdf file.
Source Ranking Database (SRD) Documentation, Vol 2, Appendices (PDF) (7.1MB, 367pp)

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.

Using AMEM

The AMEM model can be downloaded and installed using download AMEM.

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

The AMEM user's guide is available. (PDF) (13.33 MB, 158pp)

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, U.S. EPA

Office of Pollution Prevention and Toxics 
Risk Assessment Division 
e-mail: Charles Bevington

David Tobias, U.S. EPA

Office of Pollution Prevention and Toxics 
Risk Assessment Division 
e-mail: David Tobias

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