Risk and Exposure Assessment for Review of the Secondary National Ambient Air Quality Standards for Oxides of Nitrogen and Oxides of Sulfur. First Draft, Chapters 7-8

摘要

The final version of this chapter will synthesize the results of the current conditions assessments for each of the targeted ecosystem effect areas (i.e., aquatic acidification, terrestrial acidification, aquatic nutrient enrichment, and terrestrial nutrient enrichment). Further, we will use these summaries of ecological effects and their associated ecological indicators to characterize the relationship between levels of an ecological indicator and the associated degree of ecologically adverse effects. This characterization of adversity can then be used to inform policy judgments on public welfare. Once analyses are completed, the next draft of this chapter will describe the range of effects associated with the current deposition of nitrogen and sulfur and demonstrate the links between adverse ecological effects and the level of associated ecological indicators. These relationships will then be used to inform alternative standards by translating adverse effects levels into levels of ecological indicators that can be linked through atmospheric deposition to ambient air concentrations of NOx and SOx.