WPEM Q/AQ: Where can I find information about how WPEM calculates indoor air concentrations and exposures?
A: The model documentation is contained in the help screens within the model and in more detail in the Wall Paint Exposure Model (WPEM) Version 3.2 User's Guide which is available for downloading as a pdf file.
Q: Has WPEM been peer reviewed?
A: Yes. An external (i.e., by scientists outside of EPA) peer review of WPEM was conducted in 1999. Revisions to the model in response to the peer reviewers' comments were completed in March, 2001.
Q: Has WPEM been evaluated to ensure that the model calculations are being done correctly and that the results are consistent with measured results in a test house?
A: Yes. See Appendix E of the WPEM User's manual.
Q: Does WPEM contain more than one default scenario?
A: Yes. In the 'Painting Scenario' screen, click on "DESCRIPTIONS OF DEFAULT SCENARIOS" and make a note of the scenario that best meets your needs. To open that file, click on "File" at the top left hand corner of the screen, then click "Open" and select the file name you noted.
Q: The chemical I want to model does meet the requirements for a valid chemical (e.g., the chemical's vapor pressure and molecular weight are out of the range of those tested or it is a chemical that is generated during the curing or drying process), can I still use WPEM to estimate exposure?
A: You can use WPEM if you have you have emissions data from chamber studies. The emission rate of a chemical 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). Instruction for how to enter emissions data into WPEM is provided in a help screen on the "Paint & Chemical" page by clicking the '?' next to the Paint Emissions and Primer Emissions buttons at the bottom right hand side of the screen.
Q: Can I use WPEM to estimate the exposure to other wet products such as floor vanish?
A: No. WPEM is not valid for products other than latex and alkyd interior wall paints.