@conference {11809, title = {A Study of Ambient Air Quality and Visibility in National Parks}, booktitle = {2nd Conference on Scientific Research in the National Parks}, year = {1979}, month = {November 26-30}, pages = {130}, publisher = {Virginia Polytechnic Institute}, organization = {Virginia Polytechnic Institute}, keywords = {Air quality, Flora, Vegetation monitoring}, author = {Stephens, N. Thomas and Larson, Gary L and Albee, Thomas F} }