Pollution of the Stratosphere

Ozone in the stratosphere is vital to life on Earth. Yet it is chemically unstable and is susceptible to catalytic destruction from a long list of chemical substances, including NO X , HO X , CIO X , and metal oxides. In the stratosphere, these catalysts can be very active in ozone destruction, even when present at only one part of catalyst per 10,000 of ozone. Pollutants can reach the stratosphere in two ways: (1) by direct injection, as from supersonic transports, military aircraft, rockets, or nuclear bombs, and (2) by indirect injection from the troposphere, which may occur for inert, water-insoluble substances that will eventually work their way up into the stratosphere. The mass of catalysts sufficient to destroy stratospheric ozone at a significant, world-wide rate is less than the mass of the annual waste products from several industrial operations. In particular, the mass of nitrogen oxides from the exhausts of 500 supersonic transports is far above the threshold for significant catalytic destruction of ozone. This could have profound effects on the working and very maintenance of the biosphere.