CHAD is a database that includes many useful activity pattern data sets, and can be downloaded from the USEPA website. It includes the National Human Activity Pattern Survey (NHAPS) data.

From the website: " [The] Consolidated Human Activity Database (CHAD) contains data obtained from pre-existing human activity studies that were collected at city, state, and national levels. CHAD is intended to be an input file for exposure/intake dose modeling and/or statistical analysis. CHAD is a master database providing access to other human activity databases using a consistent format. This facilitates access and retrieval of activity/and questionnaire information from those databases that EPA currently has access to and uses in its various regulatory analyses ...."

Since children may be at higher risk of adverse health than adults from exposure to toxic pollutants in air, food, and soil -- due to their smaller, developing bodies, and their potential for prolonged contact with soil and dust -- a child-specific exposure factors handbook has been created by the U.S. Environmental Protection Agency.

From the website: "The document provides a summary of the available and up-to-date statistical data on various factors assessing children exposures. These factors include drinking water consumption, soil ingestion, inhalation rates, dermal factors including skin area and soil adherence factors, consumption of fruits and vegetables, fish, meats, dairy products, homegrown foods, breast milk, activity patterns, body weight, consumer products and life expectancy."

The U.S. Environmental Protection Agency's Exposure Factors Handbook is a useful compilation of data relevant to the assessment of human exposure to environmental pollutants. It provides quantitative inputs for exposure models, including human activity patterns, building characteristics, and physical characteristics of humans.

The U.S. Center for Disease Control (CDC) provides valuable exposure information on Americans for a wide variety of environmental chemicals.

From the website: "The National Report on Human Exposure to Environmental Chemicals provides an ongoing assessment of the U.S. population's exposure to environmental chemicals using biomonitoring. Biomonitoring is the assessment of human exposure to chemicals by measuring the chemicals or their metabolites in human specimens such as blood or urine."

The SimSmoke.Org website hosts on-line tools for simulating exposure to secondhand tobacco smoke in a variety of locations, including homes, cars, bars, restaurants, etc. The models can be executed from your web browser.

The R system is a Free Software programming environment for creating advanced applications in statistics, data analysis, simulation, and graphics. The system has add-on packages for graphical user interfaces, data bases, specialized plotting, and many other areas.

Expofacts is an extensive online repository of datasets containing information on numerous exposure-related factors representative of European countries.