Recent concern for the environment has made ozone a household word, yet few people understand exactly what it is or how it affects our way of life. Ozone can be thought of as a " supercharged," or high-energy, form of oxygen. The ordinary form of oxygen molecule has two oxygen atoms; ozone has three such atoms connected in a ring. In the upper atmosphere, ozone protects all life on Earth from harmful solar radiation, but ozone at the Earth's surface is a harmful pollutant.

Events leading to the discovery of the ozone began in the late 1700s, when oxygen was discovered. As more chemists began to experiment with this new gas, they found that it gave off a peculiar smell when it was sparked with electricity. In 1785, a Dutch chemist named Martin van Marum (1750-1837) first noted the similarity of this mysterious odor to the burning smell produced by...