FIGURE 3.1 Satellite image, acquired by NASA’s Earth-Probe TOMS (Total Ozone Mapping Spectrometer) satellite instrument on June 23, 1998, showing an African dust event extending from the western Sahara to the Caribbean and Florida. The TOMS aerosol index is a relative measure of absorbing aerosol particles suspended in the atmosphere; the higher the index (warmer colors), the greater the particle load.

SOURCE: Kellogg et al. (2004).


Only a few natural materials are inherently hazardous, and few are sufficiently accessible or mobile to pose a health risk in unperturbed landscapes. Asthma—a chronic condition consisting of airway inflammation and bronchoconstriction—is an example where earth material particulate matter can have adverse health effects. Current research suggests that asthma is caused by a combination of genetic and environmental factors but that particulate matter inhalation increases the severity of asthma (NASA, 2001).

Humans have a history of using specific elements from the environment, thereby changing the natural surficial distributions of rock material, soil, and botanical ground cover. At many mining sites, for example, this has led to several-fold increases of earth-sourced airborne particulate matter and increased human exposure to potentially hazardous materials. In such environments, ground-based ambient air sample data combined with spatially located health data can demonstrate the impacts of such exposure. Surface measurements of aerosol emissions identify the source and site of origin and, through analyses of the particulate matter, the composition of the potential hazards. On a local scale, integration of

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