[1] US EPA, Atmospher Modeling & Anal Div, Res Triangle Pk, NC 27711 USA
[2] US EPA, Off Air & Radiat, Off Policy Anal & Review, Washington, DC 20460 USA
[3] Joint Res Ctr, Inst Environm & Sustainabil, Ispra, Italy
[4] Comp Sci Corp, Res Triangle Pk, NC 27711 USA