1. Ecosystems Res. Div., National Exposure Res. Lab., U.S. Environmental Protection Agency960 College Station Rd.AthensGA30605
2. E.I. duPont de Nemours & CompanyExperiment Station, Bldg. 361WilmingtonDE19880
3. Atmospheric Sciences Modeling Div,, Air Resources Lab.National Oceanic and Atmospheric AdministrationResearch Triangle Park, MA on assignment to National Exposure Res. Lab., U.S. Environmental Protection Agency