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TRENDS IN RURAL SULFUR CONCENTRATIONS
Citation:
Holland, D M., P. Caragea, AND R. L. Smith. TRENDS IN RURAL SULFUR CONCENTRATIONS. Presented at International Conference on Environmental Statistics and Health, Santiago de Compostela, Spain, July 16-18, 2003.
Impact/Purpose:
Our main objective is to assess the exposure of selected ecosystems to specific atmospheric stressors. More precisely, we will analyze and interpret environmental quality (primarily atmospheric) data to document observable changes in environmental stressors that may be associated with legislatively-mandated emissions reductions.
Description:
This paper presents an analysis of regional trends in atmospheric concentrations in sulfur dioxide (502) and particulate sulfate (50~- ) at rural monitoring sites in the Clean Air Act Status and Trends Monitoring Network (CAsTNet) from 1990 to 1999. A two-stage approach is used to estimate regional trends and standard errors in the Midwest and Mid-Atlantic regions of the U .5. In the first stage, a linear regression model is used to estimate site-specific trends in data adjusted for the effects of season and meteorology. In the second stage, kriging methodology based on maximum likelihood estimation is used to estimate regional trends and standard errors. The method is extended to include a Bayesian analysis to account for the uncertainty in estimating the spatial covariance parameters. Both spatial prediction techniques produced similar results in terms of regional trends and standard errors.