Featured Fact Sheet
Top Questions About Exposure Research
- Why is Exposure Research Important?
- What Does Environmental Exposure Research Involve?
- How Does EPA Conduct Exposure Research?
Exposure is the contact of people and other organisms with an environmental stressor for a specific duration of time. Environmental stressors can include chemical pollutants; microbes or pathogens; or physical agents, like radiation; or even processes such as alteration of wildlife habitat.
In order to protect human health and the environment, EPA must understand the risks of pollutants and other stressors.
Exposure assessment is one critical input used by EPA and others to assess those risks. Chemicals that are quite toxic may not pose much risk if exposures are low. Conversely, relatively nontoxic stressors may pose big risks if people or wildlife are highly exposed.
Understanding exposure is important when assessing risks that arise from new technologies, policies and regulations, increased population growth, changes in energy use, or even fluctuations in the economy.
EPA's Exposure Research improves risk assessment through:
- Characterizing pollution sources;
- Developing environmental fate and transport computer models that can be used to quantify how risk management options are likely to affect exposures;
- Developing and enhancing measurement methods for pollutants and exposure indicators; and
- Developing exposure models that reflect individual behaviors and microenvironments.
Exposure measurements, methods, and models also are important in:
- Determining whether a pollutant or stressor represents an unacceptable risk;
- Selecting the most appropriate approaches to reduce risk; and
- Tracking compliance with environmental regulations and achieving environmental goals.
Assessing environmental exposure involves a number of elements:
- Characterizing pollution sources, including mobile sources like automobiles; point sources like industrial plants; and non-point sources like agricultural run-off and land-management habits.
- Understanding and modeling processes that control distribution, transport, transformation, and fate of pollutants or stressors as they move through the environment from sources to "receptors" (humans, plants, animals or ecosystems exposed to stressors).
- Characterizing actual exposure, including measuring and modeling how humans and ecosystems come into contact with pollutants or stressors. Studying environmental exposure involves consideration of both the pollutant-stressor and the "receptor" (e.g., the human or ecosystem which is exposed), together with duration of exposure. For this reason, exposure assessments require a variety of efforts, including:
- Measuring and modeling pollutants and stressors in various media — for example, measuring pollutant levels in the food people eat, the water they drink, the air they breathe, and the things they touch; and
- Profiling the behavior patterns of people or animals that affect their exposure — including characterizing the daily activities of people (the what, when, where and how long) that bring them into contact with pollutants.
- Assessing the effectiveness of an exposure, including making measurements to give evidence that "receptors" have been exposed. EPA's exposure research includes: determination and modeling of uptake or transfer efficiencies; modeling dose to target organs; characterizing the signs of exposure, like measuring biological markers of exposure in people or animals; finding antibodies in humans from exposure to pathogens; describing changes in wetlands or forest cover; and measuring changes in an ecosystem’s make-up.
EPA’s exposure scientists work closely with scientists across many other disciplines, including toxicology, chemistry, and geology, as well as with research staff in other federal agencies, states, industry, utilities, universities, and non-profit organizations around the world.
Research and Technical Support for Regulatory Programs
EPA exposure scientists provide research and regulatory technical support to EPA program and regional offices, states, and foreign governments. In particular, EPA’s Exposure Research Program supports regulatory monitoring methods, waste site characterization, computer modeling of pollutant transport and fate, remote sensing, monitoring network design, environmental indicators, and exposure assessment study design. EPA communicates its research products to program offices, the public, and the international community though many mediums.