OZONE Read the following article about the ozone layer. The atmosphere is an ocean of air and a natural resource for sustaining life on the Earth. Unfortunately, human activities based on personal interests are causing harm to this common resource, notably by depleting the fragile ozone layer, which acts as a protective shield for life on the Earth. Ozone molecules consist of three oxygen atoms, as opposed to oxygen molecules which consist of two oxygen atoms. Ozone molecules are exceedingly rare: fewer than ten in every million molecules of air. However, for nearly a billion years, their presence in the atmosphere has played a vital role in safeguarding life on Earth. Depending on where it is located, ozone can either protect or harm life on Earth. The ozone in the troposphere \(up to 10 kilometres above the Earth’s surface\) is “bad” ozone which can damage lung tissues and plants. But about 90 percent of ozone found in the stratosphere \(between 10 and 40 kilometres above the Earth’s surface\) is “good” ozone which plays a beneficial role by absorbing dangerous ultraviolet \(UV\-B\) radiation from the Sun. Without this beneficial ozone layer, humans would be more susceptible to certain diseases due to the increased incidence of ultra-violet rays from the Sun. In the last decades the amount of ozone has decreased. In 1974 it was hypothesised that chlorofluorocarbons \(CFCs\) could be a cause for this. Until 1987, scientific assessment of the cause-effect relationship was not convincing enough to implicate CFCs. However, in September 1987, diplomats from around the world met in Montreal \(Canada\) and agreed to set sharp limits to the use of CFCs.

Is the ozone that is formed during thunderstorms “bad ozone” or “good ozone”?