Ozone hole over Antarctica(above). Photo courtesy of NASA

Background

Ozone (O3) is an allotrope of oxygen (O2). However, it is much less stable. Ozone, at ground level, is one of many air pollutants which harm our respiratory system. In the Earth’s upper atmosphere, the function of ozone is to filter dangerous ultraviolet light and minimize the amount that reaches the Earth’s surface. Ozone can be found throughout the Earth’s atmosphere, though in low concentrations. Ozone, when visible, comes in the form of a pale-blue substance which has an irritating odor. At 0.1 to 1 parts-per-million (ppm) of exposure, ozone can cause headaches, irritation to our respiratory tract, as well as a burning sensation in our eyes. Ozone is mainly found in the Earth’s upper atmosphere, in what is commonly known as the ozone layer. In the upper atmosphere, ozone is mostly produced when oxygen reacts with ultraviolet light from the Sun.

Ozone found at the troposphere is currently considered a pollutant by the World Health Organization (WHO). It is formed when sunlight reacts with nitrogen oxides and hydrocarbons in the air, which forms ozone at the specific point of reaction. Although ozone is present at ground level, the highest concentrations can be found in the Earth’s upper atmosphere, as mentioned earlier. This increase in the upper atmosphere is of a greater concern as it is of great importance that the ozone layer is able to sustain itself and continue to protect the world from the harmful effects of ultraviolet light.
Ozone depletion is something which affects the entire planet. Ozone molecules can be broken down by free radical catalysts, some of the main ones being atomic bromide (Br) and atomic chlorine (Cl). In recent years, the concentrations of these two radicals have increased by a remarkable amount due to the continuous release of organohalogen compounds such as chlorofluorocarbons, better known as CFCs. Over the northern hemisphere, ozone levels have been decreasing at a steady rate of 4% per decade. However, due to an international ban of CFCs in most countries, scientists have discovered that ozone depletion may be slowing down. However, not all countries have banned the production and use of CFCs. Thus, we feel that in order for us to protect and sustain the ozone layer, effort has to be put in by the whole world as those countries which ignore the signs of ozone depletion not only end up being affect themselves, but affect everyone else as well.