Yes, significant depletion of the Arctic ozone layer now occurs in some years in the late winter/spring period (January-April). However, the maximum depletion is generally less severe than that observed in the Antarctic and is more variable from year to year. A large and recurrent “ozone hole,” as found in the Antarctic stratosphere, does not occur in the Arctic.

The depletion of the ozone layer leads, on the average, to an increase in ground-level ultraviolet radiation, because ozone is an effective absorber of ultraviolet radiation. The Sun emits radiation over a wide range of energies, with about 2% in the form of high-energy, ultraviolet (UV) radiation. Some of this UV radiation (UV-B) is especially effective in causing damage to living beings, for example, sunburn, skin cancer, and eye damage to humans.

Severe depletion of the Antarctic ozone layer was first observed in the early 1980s. Antarctic ozone depletion is seasonal, occurring primarily in late winter and spring (August-November). Peak depletion occurs in October when ozone is often completely destroyed over a range of altitudes, reducing overhead total ozone by as much as two-thirds at some locations. This severe depletion creates the “ozone hole” in ../images of Antarctic total ozone made from space.

The ozone layer has been depleted gradually since 1980 and now is about an average of 3% lower over the globe. The depletion, which exceeds the natural variations of the ozone layer, is very small near the equator and increases with latitude toward the poles. The large average depletion in polar regions is primarily a result of the late winter/spring ozone destruction that occurs there annually.

The ozone layer is a thin layer of gases that surrounds the earth. It acts as a sunscreen for the earth, blocking out most of the sun's UV radiation. Over the last few years, the ozone layer has become slightly thinner, allowing more damaging UV rays to reach the earth's surface than before.

Stratospheric ozone depletion, caused by increasing concentrations of human-produced chemicals, has increased since the 1980s. The springtime loss in Antarctica is the largest depletion. Currently, in nonpolar regions, the ozone layer has been depleted up to several percent compared with that of two decades ago. the figure below indicates, the magnitude of ozone depletion varies between the regions of the Earth.

Ozone depletion occurs when the natural balance between the production and destruction of stratospheric ozone is tipped in favour of destruction. Observations of an antarctic ozone "hole" and atmospheric records indicating seasonal declines in global ozone levels provide strong evidence that global ozone depletion is occurring. Although natural phenomena can cause temporary ozone loss, chlorine and bromine released from synthetic compounds are now accepted as the main cause of this depletion.

Significant reductions in ozone content in the stratosphere above the Arctic have been observed during the late winter and early spring (January-March) in 6 of the last 9 years. However, these reductions, typically 20-25%, are much smaller than those observed currently each spring over the Antarctic (the ozone hole). The difference between ozone content in the two polar regions (see figure below) is caused by dissimilar weather patterns.

No, ozone depletion itself is not the principal cause of climate change. However, because ozone is a greenhouse gas, ozone changes and climate change are linked in important ways. Stratospheric ozone depletion and increases in global tropospheric ozone that have occurred in recent decades both contribute to climate change. These contributions to climate change are significant but small compared with the total contribution from all other greenhouse gases.

The human health and environmental concerns about ozone layer depletion are different from the risks we face from global warming. Nevertheless, the two phenomena are related in certain ways. Some pollutants contribute to both problems and both alter the global atmosphere. Ozone layer depletion allows more harmful ultraviolet (UV) radiation to reach our planet?s surface.

Yes. If concentrations of ozone-destroying chemicals are reduced, the natural balance between ozone creation and destruction can be restored. However, this might require the complete elimination of CFCs, halons, carbon tetrachloride, methyl chloroform, HCFCs, and methyl bromide.

Ozone is very rare in our atmosphere, averaging about three molecules of ozone for every 10 million air molecules. In spite of this small amount, ozone plays vital roles in the atmosphere. This document provides answers to some of the questions that are most frequently asked about ozone and the changes that have been occurring in recent years.

In the strictest sense, the Arctic is all of the Earth north of the Arctic Circle, which is located at 66 degrees, 32 minutes North Latitude. However, there are other definitions to suit specific scientific or political interests. For instance, the U.S. Congress has decreed that all of the Bering Sea, which extends southward to about 53 degrees North Latitude, is part of the Arctic for internal U.S. planning and budgeting purposes.

Long-term trends in cloud type and amount are largely unknown due to the relatively short data record of comprehensive cloud observations, and the high variability of clouds on inter-annual and longer time scales. Some evidence exists showing that, at least over the time span of satellite-based ozone measurements, changes in cloud cover have been much less important than stratospheric ozone reductions in causing surface UV changes.

With regard to the ozone depletion properties of refrigerants, the ozone depletion factors are as follows: