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REGIONAL TRENDS IN RURAL SULFUR DIOXIDE CONCENTRATIONS OVER THE EASTERN U.S.
Holland, D M., P. Caragca, AND R. L. Smith. REGIONAL TRENDS IN RURAL SULFUR DIOXIDE CONCENTRATIONS OVER THE EASTERN U.S. Presented at 23rd European Meeting of Statisticians, Funchal, Portugal, August 13-18, 2001.
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.
Emission reductions were mandated in the Clean Air Art Amendments of 1990 with the expectation that they would result in corresponding reductions in air pollution. The 1990 amendments include new requirements that appreciably reduced sulfur dioxide (SO2) emissions in two phases occurring around 1995 and 2000, The estimation of emission-related trends in S02 concentrations has been the subject of many investigations since the implementation) of national monitoring networks in the late 1970's. Most of these studies focused on developing models either for site-specific trends or for trend in a summary statistic that represents a network-typical value. In recent years, the focus of environmental policy has shifted toward regional-scale strategies that require regional estimates of trimmed for both their development and subsequent evaluation. In an effort to provide meaningful regional trend information, we propose a two-stage modeling app-roach to estimate emission-related trends in rural airborne of S02 for 1990-1998. The first stage uses a linear additive model to estimate site-specific trend, and the second stage uses an extension of classical Kriging methodology to estimate regional trends and standard errors. Finally, Bayesian techniques are used to estimate standard errors to quantify the effect of ignoring the uncertainty of the spatial covariance parameters.
Record Details:Record Type: DOCUMENT (PRESENTATION/ABSTRACT)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL EXPOSURE RESEARCH LABORATORY
ENVIRONMENTAL SCIENCES DIVISION
LANDSCAPE CHARACTERIZATION BRANCH (RTP)