Effect of surface ozone exposures on vegetation grown in the Southern Appalachian 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-response effects data for deciduous and coniferous seedlings and/or trees with characterized 03 ambient exposure data for a local area and soil moisture to identify areas that may be at risk in the Southern Appalachian Mountains. Results from seedling and tree experiments operated in open-top chambers were used to characterize 0 3 exposure regimes that resulted in growth loss under controlled conditions. Available 0 3 monitoring data were characterized for the states of Alabama, Georgia, South Carolina, North Carolina, West Virginia, Tennessee, Kentucky, and Virginia, using the W126 biologically based cumulative exposure index. As a part of the analysis, both the occurrences of hourly average 03 concentrations ⩾ 0.10 ppm and the soil moisture conditions in the geographic area were considered. Combining exposure information with moisture availability and experimental exposure-response 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 from individual tree seedlings grown in chambers and pots and additional research is needed to identify what differences in effects might be observed if exposures were similar to those experienced in forests. Furthermore, we recommend future investigations to verify the location and presence of specific vegetation species and amounts and whether actual growth losses occurred in those areas of concern that have been identified in this study.