A National Assessment of the Ecological Effects of Nitrogen and Sulfur Oxides

Tara Greaver1, Meredith Lassiter2, Jeff Herrick3, Joe Pinto4, Alan Talhelm5, Emmi Felker-Quinn6, Ginger Tennant7 and Randy Waite8

The current secondary National Ambient Air Quality Standards (NAAQS) for Oxides of Nitrogen and Sulfur (NOx and SOx) review started in the Fall of 2013. The scope of the review includes the atmospheric chemistry and ecological effects of nitrogen and sulfur deposition, in addition to NOx and SOx direct effects on US ecosystems. The Integrated Science Assessment (ISA) for NOx and SOx-Ecological Criteria is the scientific foundation for the review of the secondary NAAQS for NOx and SOx. The key ecological effects that occur under current levels of air pollution are ecosystem acidification (due to NOx, NHx and SOx), nitrogen enrichment/eutrophication (due to NOx and reduced nitrogen-NHx) and sulfur enrichment.  The ISA for the current review is scheduled for release in 2016 and will include over 1000 new publications published since the 2008 ISA. The majority of new publications  since 2008 (~400) are on the effects of N deposition/addition on terrestrial ecosystems, with over 130 papers each on freshwater acidification and freshwater eutrophication. In general, since 2008, there are a number of new studies on biogeochemical and physiological mechanisms,  more syntheses such as meta-analyses, more regional scale evaluations and critical loads. This presentation will highlight progress and next steps in the ISA development.

 

1Environmental Protection Agency, greaver.tara@epa.gov
2Environmental Protection Agency, Office Research and Development
3Environmental Protection Agency, Office Research and Development
4Environmental Protection Agency, Office Research and Development
5Environmental Protection Agency, Office Research and Development
6Environmental Protection Agency, Office Research and Development
7Environmental Protection Agency, Office of Air Quality Planning and Standards
8Environmental Protection Agency, Office of Air Quality Planning and Standards