E&S Environmental Chemistry, Inc. was contracted by the U.S. EPA to draft a synthesis report on ecological effects of atmospheric deposition of oxides of sulfur (S) and nitrogen (N). This Integrated Science Assessment (ISA) was a synthesis and evaluation of the most policy-relevant science that formed the scientific foundation for the 2008 review of the secondary (welfare-based) national ambient air quality standards (NAAQS) for oxides of nitrogen (NOx) and oxides of sulfur (SOx). The Clean Air Act definition of welfare effects includes, but is not limited to, effects on soils, water, wildlife, vegetation, visibility, weather, and climate, as well as effects on man-made materials, economic values, and personal comfort and well-being. A journal article was published, together with EPA staff and other contributing scientists. More recently, E&S, working with RTI, has been assisting the EPA with the subsequent ISA (2018-2020).