National Human Exposure Assessment Survey (NHEXAS) Data Analysis Work Group

The purpose of this project is to represent NCEA on the NERL-led NHEXAS work group and to participate in activities including analysis of data from NHEXAS and development of the NHEXAS data base.

Project Status

The workgroup is no longer active. The database was released in 2002, but is no longer publically available.

Project Start Date


Project Completion Date (Actual/Projected)



Three field studies were under conducted the National Human Exposure Assessment Survey. These studies measured exposures in three study regions - Arizona, the six EPA Region V States (Ohio, Indiana, Michigan, Illinois, Wisconsin, Minnesota), and Baltimore and four surrounding counties. These studies: 1) measured pollutant concentrations in air, water, soil, dust, food, blood, urine and hair and on surfaces and human skin using various sampling and analytical techniques, 2) determined direct exposure using personal exposure monitors, and 3) estimated human activity patterns using a series of questionnaires and diaries. Respondents were selected randomly using a stratified probability sample, so that inferences could be made about the exposures of the populations from which the samples were drawn. These data will be used to estimate human exposures among the sampled populations and to test a series of hypotheses related to these exposures. Target chemicals include volatile organic compounds (VOCs), pesticides, metals and polyaromatic hydrocarbons (PAHs).

Two relatively large cross-sectional studies (150-300 respondents completing the protocol) were conducted in Arizona and in EPA Region 5. A special study of children's exposure to pesticides was conducted in Minnesota. A special study was also conducted among approximately 60 participants in 4 counties in Maryland, including Baltimore City, where people were revisited 6 times over a 1-year period.

In 2002, the NHEXAS data was publically released on the Internet. In 2001 a workshop was held and in 2002, the work group completed a report on "lessons learned," documenting observations of the the Principle Investigators of the NHEXAS collaborating organizations on project management, study design, sample collection and analysis, data analysis and database development, and communication.