Organizational components and structural features of EPA's new Human Exposure Research Program.

Modern technology has brought about a dramatic increase in the production and consumption of man-made chemicals and in their resulting emissions. It is clear that these emissions and their by-products will likely affect our environment and have a health impact on the population exposed to them. Knowledge of exposure is required to document the impact of these emissions on human health. However, measuring, interpreting, and characterizing human exposures are extraordinarily complex processes because exposures may occur by multiple routes, multiple sources, and they are subject to a wide range of temporal, spatial, and source variations often from both anthropogenic and non-anthropogenic sources. The Environmental Protection Agency's approach to exposure research has often been insufficient to understand and mitigate these complex real-word exposures. For example, we do not know the population exposure distributions of most pollutants and the relative contributions of sources to these distributions. Without this knowledge as input into EPA's risk management process, EPA's may not be making the most effective environmental management decisions for reducing human health risks. The Human Exposure Research Program is a direct response to this need to understand how and to what extent humans are exposed to environmental pollutants.