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STATISTICAL METHOD FOR DETECTION OF A TREND IN ATMOSPHERIC SULFATE
Citation:
Shreffler, J. AND H. Barnes. STATISTICAL METHOD FOR DETECTION OF A TREND IN ATMOSPHERIC SULFATE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/A-95/026 (NTIS PB95174686).
Description:
Daily atmospheric concentrations of sulfate collected in northeastern Pennsylvania are regressed against meteorological factors, ozone, and time in order to determine if a significant trend in sulfate can be detected. he data used in this analysis were collected during the Sulfate Regional Experiment (SURE, 1977-1978) and the Acid Model Operational Diagnostic Evaluation Study (Acid MODES, 1988-1989). he steps in building a multiple linear regression model for sulfate are discussed. zone and seasonal terms (reflecting the potential of the atmosphere for oxidation of sulfur dioxide) emerge as important explanatory factors. fter accounting for the variability explained by other important environmental factors, the calculated change in sulfate over the eleven year period is -32 percent with 95% CI (-26,-37). his change is commensurate with an estimated 25 percent decline in sulfur emissions in the northeastern U.S. during the same period. otential problems associated with different measurement methods and different site locations in the two studies are discussed. hese analyses provide insight into methods for detecting reductions in sulfate that may be expected to occur as a result of the Clean Air Act Amendments of 1990.