Risk Assessment

# Options for Development of Parametric Probability Distributions for Exposure Factors

### Report Information

Users of the **Exposure Factors Handbook** (EPA/600/P-95/002Fa-Fc) expressed the need to fit distributions to the data in the handbook to assist them when applying probabilistic methods to exposure assessments. The purpose of this document is to fulfill this need. The document summarizes a system of procedures to fit distributions to selected data from the Exposure Factors Handbook. Three factors - tap water intake, population mobility, and inhalation rules - are used at test cases in the document. The system used includes components for models, estimation, assessment of fit, and uncertainty. Eight models were tested including: generalized F, generalized gamma, Burr, gamma, lognormal, Weibull, log-logistic, and exponential. The document provides recommendations on the models that provide the best fit.

- by phone at: 703-347-8539
- by email at: moya.jacqueline@epa.gov

### Citation

### Downloads

- Table of Contents for EPA/600/R-00/058 (PDF) (NA pp, 51 KB, about PDF)
- Chapter 1: Introduction (PDF) (NA pp, 225 KB, about PDF)
- Chapter 2: A System for Fitting Distributions to Exposure Factor Data (PDF) (NA pp, 57 KB, about PDF)
- Chapter 3: Analysis of Tap Water Data (PDF) (NA pp, 243 KB, about PDF)
- Chapter 4: Analysis of Population Mobility Data (PDF) (NA pp, 27 KB, about PDF)
- Chapter 5: Application to Inhalation Rates (PDF) (NA pp, 29 KB, about PDF)
- Chapter 6: Discussion and Recommendations (PDF) (NA pp, 31 KB, about PDF)
- Chapter 7: References (PDF) (NA pp, 23 KB, about PDF)
- Appendix A: Glossary (PDF) (NA pp, 43 KB, about PDF)
- Appendix B: Fitting Models to Percentile Data (PDF) (NA pp, 26 KB, about PDF)
- Appendix C: Fitting Quantiles By Combining Nonlinear and Linear Regression (PDF) (NA pp, 25 KB, about PDF)
- Appendix D: the Generalized (Power Transformed)F Family of Nonnegative Probability Distributions (PDF) (NA pp, 300 KB, about PDF)