This article will review current information regarding the ozone layer of Earth's upper atmosphere, damage being done to the ozone layer related to natural and human activities. Engineering solutions designed to eliminate further depletion of the ozone layer will be presented.
The ozone (O3) layer refers to the layer within Earth's upper atmosphere lying between 50,000 to 120,000 feet (Ozone layer, 1984, 2127). In forming ozone, ultraviolet radiation of wavelengths between 290 and 320 nanometers are absorbed by oxygen molecules (O2) forming a high energy bond between three atoms of oxygen (O3) (Ozone layer..., 1984, 2127).
Ozone thus generated in the upper atmosphere absorbs 97 99% of the sun's high frequency ultraviolet light, protecting life on Earth from exposure to potentially higher levels of ultraviolet (UV) radiation (Ozone home..., 1996).
Unstable ozone molecules are also constantly being created and destroyed by complex natural forces involving solar radiation and interactions with very minute quantities of other gases. Ozone concentrations fluctuate naturally on a daily, seasonal, and solar cyclical basis (Mathews, 1991, 115).
Ozone concentration is measured in Dobson units. The instrumentation designed by G.M.B. Dobson measures ozone concentrations using the relative intensity of solar radiation at four wavelengths. Two of these wavelengths are absorbed by ozone and two are not. This provides a consistent system of internal cross checking. The average thickness of the ozone layer over the U.S. is about 300 DU. In absolute terms, 1 DU is about 2.7X 10 16 molecules/cm 2. Concentrations over the Antarctic in late spring can drop to 117 DU (Ozone home..., 1996). Unfortunately, since records of ozone concentrations have only been kept the 1920s, a definable 'normal' range of ozone concentration does not exist (Penzoil, 1997).
Factors Influencing Ozone Concentrations
Although a provable established lin...