This final reading puts an ironic twist on the ozone story by introducing one of the strange complexities of environmental chemistry. While we have destroyed ozone in the stratosphere, we have generated a good deal of it close to the ground. Strangely enough, down here ozone is a dangerous pollutant, not the heroic molecular defender of UV-sensitive life forms that it is when it occurs in the upper atmosphere. As for chemical concepts, the reading reinforces understanding chemical reactions by discussing those reactions that produce ozone at ground level.

To reinforce concepts concerning ground-level ozone, you may wish to use the activity Ozone Patrol in conjunction with this reading.

Relevant National Science Education Standards

Unifying Concepts and Processes — The reading looks at one side of the complicated system of the chemistry of the earth's atmosphere.

Physical Science — The reading deals with the molecular nature of matter, chemical reactions, and the interaction of matter with energy in the form of UV radiation.

Earth and Space Science — The reading looks at some of the chemical processes occurring in the earth's atmosphere, and the involvement of energy (UV radiation) on those processes.

Science and Technology — The reading introduces an undesirable consequence of internal-combustion technology.

Science in Personal and Social Perspectives — The reading involves an environmental quality issue that is also a human-induced health hazard.

Next: Checking for Ultraviolet Radiation

AIRNOW — contains information on ground-level ozone, including ozone level maps for many states, from the U.S. Environmental Protection Agency, Office of Air Quality Planning & Standards.

Air and Health Activities — activities related to air pollution, including an ozone preparation activity, from the University of Arizona Center for Toxicology Southwest Environmental Health Sciences Center Community Outreach and Education Program Educational Resources.