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Using Bio Indicator Species to Visualize Ground-Level Ozone Pollution in Denver

Bioindicator plants are species that are more sensitive to ground level (tropospheric) ozone, and show identifiable damage when exposed to high ozone concentrations. It is important to monitor ground level ozone, as it is extremely toxic to plants and decreases the amount of carbon storage and the amount of carbon dioxide (CO2) that can be pulled from the air, decreases crop production, and weakens the plants- making them more susceptible to other issues. Bioindicator plants are so valuable because they provide visible measurements of ozone concentrations, showing the first hand effects of pollutants on the air chemistry and in turn the effects on plants. Ground level ozone is created through the reaction of sunlight, nitrogen oxides and volatile organic compounds produced from the fuel combustion of driving cars.

To understand the damage ozone is having on plants in Denver, I used two varieties of beans: a common variety that is sensitive to ozone, and a modified variety that is tolerant to ozone damage. The tolerant bean variety acted as a control group to compare the damage of the sensitive group to. These plants were cared for and their leaves were monitored for ozone damage every other day from July to October. This project shows evidence that ozone pollution is both increasing damage to the plants’ leaves and decreasing the crop production of the sensitive (common) bean varieties as compared to the tolerant varieties. It also shows that high temperature and ozone concentrations are correlated with more damage to the sensitive varieties. This data was added to a nationwide database of ozone gardens, to answer the questions of what concentration causes damage, how severe the damage can become, and how damage differs across location.