Contrary to what a lot of people think, none! 'Good' and 'bad' ozone exist (like good and bad cholesterol) but neither plays any part in global warming. The 'good' ozone is to be found 15 km above our heads in the famous ozone layer. This layer is permanent and protects us from harmful ultra violet rays emanating from the sun. The hole in the ozone is produced by chlorofluorocarbons (CFC), chloride gases which up until 1987 were used in aerosol cans and refrigerating systems.

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.

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.

Ozone's unique physical properties allow the ozone layer to act as our planet's sunscreen, providing an invisible filter to help protect all life forms from the sun's damaging ultraviolet (UV) rays. Most incoming UV radiation is absorbed by ozone and prevented from reaching the Earth's surface. Without the protective effect of ozone, life on Earth would not have evolved the way it has.

Global ozone levels declined an average of about 3 per cent between 1979 and 1991. This rate of decline is about three times faster than that recorded in the 1970's. In addition to Antarctica, ozone depletion now affects almost all of North America, Europe, Russia, Australia, New Zealand, and a sizable part of South America. Short term losses of ozone can be much greater than the long term average. In Canada, ozone depletion is usually greatest in the late winter and early spring.

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.

High up in the atmosphere, in a region called the stratosphere between 19 and 30 km above the Earth's surface, ozone is constantly being produced and destroyed naturally. This ozone layer filters out UV rays from the Sun and protects life on Earth. Usually there is a fine balance between the build up and loss of ozone.

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.

Scientists expect to detect the recovery of the ozone layer with careful comparisons of the latest ozone measurements with past values. Changes in total overhead ozone at various locations and in the extent and severity of the Antarctic “ozone hole” will be important factors in gauging ozone recovery. Natural variations in ozone amounts will limit how soon recovery can be detected with future ozone measurements.

Measuring the ozone at both poles is a 'barometer' of sorts. Though typically the ozone varies in densities and coverage at these areas, it also reflects the overall warming and depletion of the ozone worldwide. Sun shining on the poles is not filtered of harmful ultraviolet radiation due to the increasing lack of ozone.

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.

First, it's important to know that ozone plays two different roles in the atmosphere. At ground level, "bad ozone" is a pollutant caused by human activities; it's a major component of health-damaging smog. The same chemical occurs naturally in the stratosphere, and this "good ozone" acts as a shield, filtering out most of the ultraviolet light from the Sun that could otherwise prove deadly to people, animals, and plants.

Ozone is a form of oxygen that contains three atoms (O3) rather than the normal two (O2). Ozone acts as an oxidizer and disinfectant (sanitizer) in the pool. Prozone equipment is designed primarily to provide oxidation and some disinfection of the water. Ozone is the most powerful oxidant and disinfectant readily available.

The Earth System Research Laboratory's (ESRL) Global Monitoring Division (GMD), part of NOAA's Office of Oceanic and Atmospheric Research (OAR), traces its roots in ozone monitoring back to the U.S. Weather Bureau and its measurements of total column ozone as part of the International Geophysical Year (IGY), 1957. W.D. Komhyr established the U.S. Dobson network in its current form with well-characterized and calibrated instruments and standardized operating procedures in the early 1960s.

No. Because ozone reacts so quickly with contaminants in water and air, it converts back to oxygen within minutes or even seconds. Any ozone molecules that break free from the pool or spa water will convert to oxygen and never reach the atmosphere.

In 1987, the nations of the world banded together to draft the Montreal Protocol to phase out the production and use of CFCs. The 43 nations that signed the protocol agreed to freeze consumption and production of CFCs at 1986 levels by 1990, reduce them 20% by 1994, and reduce them another 30% by 1999. The alarming loss of ozone in Antarctica and worldwide continued into the 1990's, and additional amendments to further accelerate the CFC phase-out were adopted.