Exposure reconstruction using space-time information technology

In recent decades, digitally georeferenced data and geographic information systems (GIS) have played a growing role in human exposure assessment. Despite this, spatiotemporally varying datasets, such as daily activity spaces, residential histories, and time-varying maps of environmental contaminants, are poorly characterized in the GIS environment. Although GIS-based methods can integrate datasets that contain spatial or temporal variability, until recently, datasets exhibiting spatiotemporal variability have been largely unmanageable. Recent advances in space-time technology, however, enable exposure scientists to more fully incorporate spatial and temporal variability into human exposure assessment. Space-time technology allows the user to observe and quantify how geographic attributes change with time, thereby enabling powerful exposure reconstruction procedures that are not possible through “space only” GIS. The continual expansion of space-time databases, coupled with the recognized need to incorporate human mobility in environmental epidemiology, has highlighted the deficiencies of GIS-based software to visualize and process space-time information. This need is most pressing in retrospective studies where collection of individual biomarkers is unattainable or prohibitively expensive and where models and software tools are required for exposure reconstruction. Advances in space-time technology will profoundly improve the ability to reconstruct time-resolved individual exposures to environmental contaminants.