Time-space modeling of journey-time exposure to traffic-related air pollution using GIS.
Journey-time exposures represent an important, though as yet little-studied, component of human exposure to traffic-related air pollution, potentially with important health effects. Methods for assessing journey-time exposures, either as part of epidemiological studies or for policy assessment, are, however, poorly developed. This paper describes the development and testing of a GIS-based system for modeling human journey-time exposures to traffic-related air pollution: STEMS (Space-Time Exposure Modeling System). The model integrates data on source activity, pollutant dispersion, and travel behavior to derive individual- or group-level exposure measures to atmospheric pollution. The model, which is designed to simulate exposures of people as they move through a changing air pollution field, was developed, validated, and trialed in Northampton, UK. The system currently uses ArcInfo to couple four separate submodels: a source activity/emission model (SATURN), a proprietary atmospheric dispersion model (ADMS-Urban), an empirically derived background air pollution model, and a purposely designed time-activity-based exposure model (TOTEM). This paper describes the structure of the modeling system; presents results of field calibration, validation, and sensitivity analysis; and illustrates the use of the model to analyze journey-time exposures of schoolchildren.
Small Area Health Statistics Unit, Department of Epidemiology and Public Health, Imperial College London, London W2 1PG, UK. j.gulliver@imperial.ac.uk
John
J
Gulliver
David J
DJ
Briggs
D000397:Air Pollution / Q000032:analysis*; D002648:Child; D004739:England; D004781:Environmental Exposure; D040362:Geographic Information Systems; D006801:Humans; D008962:Models, Theoretical; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012984:Software; D013997:Time Factors; D014186:Transportation