FIGURE 1-1 The classic environmental-health continuum. Figure 1-2 illustrates the revised version discussed in the present report. Source: Adapted from EPA 2009a.
There are many notable examples of the roles that exposure science can play in protecting public health. Consider how measurements of childhood blood lead concentrations since the 1970s reveal the dramatic efficacy of lead removal from gasoline in reducing exposure to this neurotoxicant in children (Muntner et al. 2005; Jones et al. 2009). Population-scale measurements of co-tinine in urine document the reduction of exposure to second-hand tobacco smoke that resulted from control of tobacco-smoking in the workplace and public areas (EPA SAB 1992). Exposure modeling from the U.S. Environmental Protection Agency’s (EPA) National-Scale Air Toxics Assessment program has provided valuable information for communities on their exposure sources, concentrations, and risks and has helped to shed light on exposure disparities and environmental-justice issues (for example, Pastor et al. 2005).
Exposure science has played a critical role in understanding the influence of stressors on ecologic systems. For example, extensive exposure assessments of polycyclic aromatic hydrocarbons (PAHs) have been linked to liver damage in bottom-dwelling fish in Puget Sound, and field studies have demonstrated that containment of PAH sources has led to declines in PAH concentrations and a resulting decline in liver damage in fish (Myers et al. 2003).
Exposure science has applications in industrial, military, commercial, and global contexts. It is central to tracking chemicals and other agents that are introduced into global commerce at increasing rates, often with little information on their hazard potential (GAO 2005). Increasingly, exposure science is used for homeland security and the protection of deployed soldiers. Rapid detection of potentially harmful radiation or toxic chemicals is essential for protecting troops and the general public (IOM 2000). The ability to detect chemical contaminants in drinking water at low, biologically relevant concentrations quickly can help to identify emerging health threats, and monitoring of harmful algal blooms and airborne pollen can help to identify health-relevant effects of a changing climate.
As described in more detail in Chapter 3, applications of exposure science are critical for toxicology, epidemiology, risk assessment, and risk management. For example, toxicology provides information about how different chemical concentrations may affect public or ecologic health in laboratory studies or