Record Display for the EPA National Library Catalog


Main Title Application of a Telephotometer to Visibility Measurements in the Eastern United States.
Author Ellestad, Thomas G. ; Speer, Ronald E. ;
CORP Author Environmental Sciences Research Lab., Research Triangle Park, NC.
Year Published 1981
Report Number EPA-600/J-81-024;
Stock Number PB82-205899
Additional Subjects Visibility ; Light transmission ; Aerosols ; Light scattering ; Air pollution ; Reprints ; Extinction coefficients ; Atmospheric transmissivity ; Eastern Region(United States) ; Telephotometry ; Air quality
Library Call Number Additional Info Location Last
NTIS  PB82-205899 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 9p
Theories of light extinction and contrast reduction by atmospheric aerosols are reviewed. Measurements by a telephotometer of the relatively turbid atmosphere of the eastern U.S. are described. Because of current levels of extinction, it is feasible to apply a dual target technique first described by Ruhle, which corrects for the targets' imperfect blackness and stray light imperfections in the telephotometer optics. Measurements have been made during an intensive visibility study in the Ohio River Basin. These results compare favorably to independent measures of scattering and absorption coefficients. Complications introduced by uneven illumination due to clouds are found to be surprisingly small; only the most obvious cases of poor illumination need be excluded.