Ozone absorbs u.v. radiation which can be harmful to people and vegetation.
The gas has an irritating odor and can damage tires and plants. UV radiation causes the release of a chlorine free radical which can lead to the breakdown of thousands of ozone molecules. Methane, ammonia, and water. They study tree rings, ice and sediment cores. The plant absorbs carbon diaxide, lowers the pH, and thus causes the change in color of the indicator.