In the eastern hemisphere, local ozone destruction has exceeded 30% and can be identified with air advected from low latitudes.

However, some layers may still show complete ozone destruction by early October, when ozone depletion is greatest.

At current rates of ozone destruction, the incidence of skin cancer is expected to increase by 50 percent by the year 2040.

The threat of ozone destruction should peak in about seven years' time, according to some scientists studying the problem.

More complicated mechanisms have been discovered that lead to ozone destruction in the lower stratosphere as well.

The gas contributes to ozone destruction and the warming of the atmosphere.

The situation is exacerbated by unusually low levels of nitrogen oxides, which inhibit ozone destruction.

Though environmentalists are encouraged, reversing ozone destruction still promises to be difficult.

Chlorine concentrations build up during the polar winter, and the consequent ozone destruction is greatest when the sunlight returns in spring.

In the critical layer between 8 and 13 miles (14 and 21 kilometers) above the surface, the team found nearly complete ozone destruction.