of soils throughout the United States—remains an unrealized high-priority requirement for understanding and predicting risk. And although the detrimental health effects from some natural fibrous and asbestiform minerals have received considerable publicity over the past several decades, there is still inadequate understanding of the precise mineral species characteristics that impact human health.

Collaborative research by earth and public health scientists will be required to effectively address a range of important issues associated with airborne mixtures of pathogens and chemicalirritants:

• Exposure concentrations and dose response arising from particulate matter/microbe/chemical interactions.

• Dose response of soil microbes and pollen.

• Long-term risks from low-level concentrations of airborne particulate matter contaminants.

Pollution by wind-blown dusts and volcanic aerosols, gases, and ash is ubiquitous, and most scientists and public health officials predict that the worldwide urbanization phenomenon, combined with the expected effects of global climate change, will generate more potentially hazardous “dusts.” A complicating factor is that in most cases natural and anthropogenic air pollution consists of complex mixtures of chemical and biochemical species as well as pathogens, and the earth-sourced or earth-hosted component can be difficult to assess. Adverse effects arising from the inhalation of these species and mixtures require detailed geologic investigations of earth sources and the identification of atmospheric pathways to sites of bioaccessibility and potential ingestion by human hosts. The anticipation or prevention of air pollution−caused health effects prior to the onset of illness requires quantitative knowledge of the geospatial context of disease vectors. A combination of earth observations, using satellite and ground-based detection systems, and public health surveillance has significant potential to improve human health.