DUST-SOURCE SETTING AS A FACTOR FOR ANTICIPATING THE HEALTH RISKS OF ATMOSPHERIC DUST

Dust is emitted from diverse settings. Geologic, hydrologic, ecologic, land-use, and climatic conditions interact in these settings to determine dust composition, as well as to promote or suppress dust emission. Recent advances have been made in identifying dust sources in North America; in understanding conditions and processes of dust emission from them; and in documenting physical and chemical compositions of dust from the varied sources. This new knowledge is applicable to evaluating potentially adverse effects of dust from each source on human health. Moreover, we can commonly track dust plumes from these sources into populated areas using satellite images and predict dust emission and pathways using meteorologically-based computer simulations of wind directions and intensities.

The common potential health hazards from dust consist of (1) particulate matter (PM, mostly <10 micrometers in diameter); (2) specific minerals (e.g., asbestiform types); (3) bioavailable metals and metalloids (M); (4) pathogens (P); and (5) herbicides/pesticides (H/P). Examples of dust sources that bear on potential health hazards include sparsely vegetated arid lands (PM and P hazards); evaporative dry lakes (M hazards in saline-mineral dusts); and burned areas (PM).

The many avenues for future work range from forecasting dust emission using drought-prediction maps (based on climate and soil moisture models) to 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 future dust emission than is currently occurring there, with potential PM, P, M, and H/P effects on nearby communities.