Non-stationary spatio-temporal modeling of traffic-related pollutants in near-road environments

Publication date: Available online 28 April 2016 Source:Spatial and Spatio-temporal Epidemiology Author(s): Owais Gilani, Veronica J. Berrocal, Stuart Batterman A problem often encountered in environmental epidemiological studies assessing the health effects associated with ambient exposure to air pollution is the spatial misalignment between monitors’ locations and subjects’ actual residential locations. Several strategies have been adopted to circumvent this problem and estimate pollutants concentrations at unsampled sites, including spatial statistical or geostatistical models that rely on the assumption of stationarity to model the spatial dependence in pollution levels. Although computationally convenient, the assumption of stationarity is often untenable for pollutants concentration, particularly in the near-road environment. Building upon the work of [Fuentes, M. (2001). A high frequency kriging approach for non-stationary environmental processes. Environmetrics, 12(5):469–483.] and [Schmidt, A. M., Guttorp, P., and O’Hagan, A. (2011). Considering covariates in the covariance structure of spatial processes. Environmetrics, 22(4):487–500.], in this paper we present a non-stationary spatio-temporal model for three traffic-related pollutants in a localized near-road environment. Modeling each pollutant separately and independently, we express each pollutant’s concentration as a mixture of two independent spatial processes, each equipped with a non-st...
Source: Spatial and Spatio-temporal Epidemiology - Category: Epidemiology Source Type: research