Stream ecosystem functions and the national ambient air quality standard review for NOx and SOx

In December 2008, the National Center for Environmental Assessment (NCEA) publically released the Integrated Science Assessment (ISA) for oxides of nitrogen and sulfur (NOx and SOx)-Ecological Criteria.  Over 3400 policy-relevant scientific publications that had become available since the last assessments of NOx and SOx (1993 and 1982, respectively) were reviewed. The ISA is the scientific foundation for the review of the secondary National Ambient Air Quality Standards (NAAQS) for NOx and SOx, which is mandated under the Clean Air Act.

The main ecological effects of NOx and SOx that occur across the U.S. under current loads of atmospheric deposition are alteration of ecosystem structure and function caused by nitrogen enrichment and acidification. There are few publications on ecosystem services and valuation associated with NOx and SOx air pollution. Even though, the translation of esoteric ecological effects into ecosystem services that identify the tangible benefits or costs to human society has the potential to be a powerful tool in determining protective levels of pollution. This presentation discusses the main scientific findings of the ISA, known ecosystem services affected in freshwater ecosystems, and opportunities to better characterize stream ecosystem services in the literature for application to the NAAQS.