ANTICIPATING HEALTH RISKS FROM ATMOSPHERIC DUST THROUGH DETECTION OF SOURCES, COMPOSITIONS, AND TRANSPORT PATHS OF REGIONAL DUST

Dust is emitted from diverse settings. Geologic, hydrologic, ecologic, land-use, and climatic conditions interact in these settings to promote or suppress dust emission and to determine dust composition. New knowledge about dust sources, conditions of dust emission, and dust composition, coupled with human response to dust exposure, can be applied to evaluate potentially adverse health effects of dust. Moreover, we can track dust plumes from these sources into populated areas using satellite-image and back-trajectory analysis, as well as predict dust emission and pathways using computer simulations for wind. Potentially hazardous components of dust can include (1) specific minerals along with characteristics of size, shape, and density (M); (2) bioaccessible toxic elements (BE); (3) pathogens (P); and (4) herbicides/pesticides (H/P). Sources for major, regional dust (and their hazardous components) include sparsely vegetated arid lands (M, P); evaporative dry lakes (BE in saline minerals); agricultural and grazed landscapes (M, H/P), and burned areas (M), any of which can be mixed with industrial dusts (M, BE) in some areas. Currently, some major urban areas in the American West experience dust fall from multiple sources that emit dust with different size distributions, mineral species, and chemical compositions. An important avenue of research is to investigate whether such differences in dust properties can have variable health effects. The many paths for future work include forecasting dust emission using drought-prediction maps (based on climate and soil moisture models) and monitoring affected populations for suspected dust-composition hazards. We can also anticipate dust emission and composition from new sources on the basis of land-management policies and ensuing human actions. As one example, the planned drop in water level at Salton Sea (southern California) will likely lead to greater dust emission, with increased PM, P, BE, and H/P exposures to nearby communities.