Domestic co2 Emission Standards. Third, potential domestic reporting requirements for aviation manufacturers under the Clean Air Act. Epa has proposed endangerment findings focus on six key Greenhouse Gases but we concur with this approach with caveats. We agree with epa the assessment scientific uncertainties on the Climate Impact of nitrogen oxides or nox and water vapor emitted at altitude remain high enough so as not to address them in this initial endangerment finding. Science with black carbon to Climate Change on the other hand, is clear. Black carbon was identified as the second most important contributor to anthropogenic emissions in 2013 to. To reflect the latest icp should consider incorporating black carbon in its final aviation endangerment finding. Also while we do not support integrating crude nox under the endangerment finding, epa should consider expanding its existing nox reporting requirement for aircraft, Engine Manufacturers, landing and takeoff emissions to includ