EFFECT OF SURFACE OZONE EXPOSURES ON VEGETATION GROWN IN THE SOUTHERNAPPALACHIAN MOUNTAINS - IDENTIFICATION OF POSSIBLE AREAS OF CONCERN

The results described in this paper are derived from an analysis, for the 8-yr period 1983-1990, that combined experimental exposure-respons e effects data for deciduous and coniferous seedlings and/or trees wit h characterized O-3 ambient exposure data for a local area and soil mo isture to identify areas that may be at risk in the Southern Appalachi an Mountains. Results from seedling and tree experiments operated in o pen-top chambers were used to characterize O-3 exposure regimes that r esulted in growth loss under controlled conditions. Available O-3 moni toring data were characterized for the states of Alabama, Georgia, Sou th Carolina, North Carolina, West Virginia, Tennessee, Kentucky, and V irginia, using the W126 biologically based cumulative exposure index. As a part of the analysis, both the occurrences of hourly average O-3 concentrations greater than or equal to 0.10 ppm and the soil moisture conditions in the geographic area were considered. Combining exposure information with moisture availability and experimental exposure-resp onse data, the extreme northern and southern portions of the Southern Appalachian area were identified as having the greatest potential for possible vegetation effects. The study was based mostly on results fro m individual tree seedlings grown in chambers and pots and additional research is needed to identify what differences in effects might be ob served if exposures were similar to those experienced in forests. Furt hermore, we recommend future investigations to verify the location and presence of specific vegetation species and amounts and whether actua l growth losses occurred in those areas of concern that have been iden tified in this study. (C) 1997 Elsevier Science Ltd.