Ozone Concentration and Foliar Injury Analysis at Purchase Knob Garden

Tropospheric ozone (O3) is a common greenhouse gas, which in high concentrations is harmful to the respiratory systems of humans, animals, and certain plants. Some of these bioindicator plants have observable symptoms that arise from exposure to high ozone concentrations. We observe these plants in ozone bioindicator gardens, which have been specifically created for the purpose of observing ozone damage. In this analysis we use data from the Purchase Knob ozone garden site in the Great Smoky Mountains National Park in North Carolina with the goal of discovering the relationship between plant damage and ozone concentration. Starting with hourly O3, we calcu- lated the cumulative W126 index, which is a metric used to summarize hourly ozone concentrations and gives higher, more damaging ozone concentrations more weight. We then used a simple linear regression, modeling percentage of damaged leaves versus cumulative W126 index. We also tested a second regression model, modeling the per- centage of damaged leaves against the logarithm of cumulative W126. The logarithmic model performed better, explaining 36% of the inter-annual variability