Ozone depletion update.

BACKGROUND

Stratospheric ozone depletion due to chlorofluorocarbons an d increased ultraviolet radiation penetration has long been predicted.

OBJECTIVE

To determine if predictions of ozone depletion are correct and, if so, the significance of this depletion.

METHODS

Review of the English literature regarding ozone depletion and solar ultraviolet radiation.

RESULTS

The ozone layer is showing definite thinning. Recently, significantly increased ultraviolet radiation transmission has been detected at ground level at several metering stations. It appears that man-made aerosols (air pollution) block increased UVB transmission in urban areas. Recent satellite measurements of stratospheric fluorine levels more directly implicate chlorofluorocarbons as a major source of catalytic stratospheric chlorine, although natural sources may account for up to 40% of stratospheric chlorine.

CONCLUSIONS

Stratospheric chlorine concentrations, and resultant increased ozone destruction, will be enhanced for at least the next 70 years. The potential for increased transmission of ultraviolet radiation will exist for the next several hundred years. While little damage due to increased ultraviolet radiation has occurred so far, the potential for long-term problems is great.