• What does MCCEM do?
• How does MCCEM work?
• What do I need to use MCCEM?
• How are MCCEM data used?
• What type of computer system do I need?
• What is MCCEM's status and availability?

What does MCCEM do?

• Estimates average and peak indoor air concentrations of chemicals released from products or materials in houses, apartments, townhouses, or other residences. 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 actual absorption into the body.)

How does MCCEM work?

• MCCEM is a user-friendly software product that estimates indoor air concentrations using a mass balance approach.
• Maintains a library of residences, containing data on zone or area volumes, interzonal air flows, and whole-house exchange rates.
• Allows you to tailor your analysis to a particular location, and to model air concentrations in as many as four zones for a given residence.
• Estimates exposure for periods ranging from 1 hour to 1 year. Develops seasonal or annual exposure profiles using a long-term model.
• Offers several different options for dealing with 'sinks'. A sink is a material (e.g., carpeting, wallboard) that can absorb chemicals from the air; the absorption can be either reversible or irreversible.

What do I need to use MCCEM?

• Data on the indoor environment to be modeled, including type of residence, zone volumes, inter-zonal air flow rates, and air exchange rates. You can enter your own site-specific data or access the model's library to select default data from different types of residences in various geographic areas.
• A measured or estimated pollutant emission rate as a function of time.
• Rate constants and areas for the sinks (sinks are optional and do not need to be used to run MCCEM).
• Occupant activity pattern (for inhalation exposure calculations).

How are MCCEM data used?

You can use MCCEM to estimate inhalation exposures to chemicals released from products or materials in residential settings or other indoor environments.

What type of computer system do I need?

• The program is now available for use in a Windows 95 operating environment.
• Hardware: IBM-compatible computer with 16K RAM and a pentium processor.
• Software: Windows 95 operating system.

What is MCCEM's status and availability?

MCCEM has been peer reviewed by experts outside the EPA. MCCEM was developed under contract by Versar Inc. for the EPA Office of Pollution Prevention and Toxics, Economics, Exposure, and Technology Division, Exposure Assessment Branch (EAB).

Download MCCEM

MCCEM can be downloaded and installed using Download MCCEM.

Description of Updates for MCCEM Version 1.2 (February 2001)

MCCEM Questions/Answers

• Where can I find information about how MCCEM calculates indoor air concentrations and exposures?

  The model documentation is contained in the help screens within the model.

• Has MCCEM been peer reviewed?

  An external (i.e., by scientists outside of EPA) peer review of MCCEM was conducted in 1998. Revisions to the model in response to the peer reviewers' comments was completed in April, 1999.

• Has MCCEM been evaluated to ensure that the model calculations are being done correctly?

  Yes. See the model evaluation help screen in MCCEM.

• One of the required inputs to MCCEM is an emission rate. How can I obtain this input?

  The emission rate of a chemical from an indoor source sometimes can be estimated (e.g. the rate at which a volatile chemical is released from an aerosol consumer product) or it can be measured using small or large testing chambers. The American Society for Testing and Materials (ASTM) has published a standard guide for small chamber testing of organic emissions from indoor materials and products. (ASTM D 5116-90).

For more information about the model, contact:
Christina Cinalli
U.S. Environmental Protection Agency
1200 Pennsylvania Avenue N.W.
Washington, DC 20460
Mail Code 7406M
Phone #: (202) 564-8542
e-mail: cinalli.christina@epa.gov