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Trends in Rural Sulfur Concentrations

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Abstract:As the focus of environmental management has shifted toward regional- scale strategies, there is a growing need to develop statistical methodology for the estimation of regional trends in air pollution. This information is critical to assessing the effects of legislated emission control programs. This paper presents an analysis of trends in atmospheric concentrations of sulfur dioxide (SO2) and particulate sulfate (SO,'-) 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.S. 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. This method is extended to include a Bayesian analysis to allow more accurate determination of the prediction error variance that accounts for uncertainty in estimating the spatial covariance parameters. For both pollutants, significant improvement in air quality was detected that appears similar to the large drop in S02 power plant emissions. Spatial patterns of trends in S02 and SO,2- concentrations vary by location over the eastern United States. Both spatial prediction techniques produced similar results in terms of regional trends and standard errors.
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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.
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Contact: Chris Siebert - (702) 798-2234 or siebert.christopher@epa.gov
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Division: Environmental Sciences Division
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Branch: Landscape Characterization Branch (RTP)
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Product Type: Abstrct/Oral
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Presented: 07/16/2003
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Related Entries:
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Bullet Item Atmospheric Ecosystem Stressor Pattern and Trend Analysis
spacer Relationship Reason:   A Project of the Product
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Bullet Item Environmental Statistics Initiative
spacer Relationship Reason:   A Project of the Product
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Last Updated on Monday, October 22, 2007
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