The ozone layer is essentially Mather Earth’s safety net, residing some 50 kilometres above the planet’s surface. Created from O3, or ozone gas, it is up to 20 kilometres thick and 90 per cent of this gas can be found up on the Earth’s stratosphere. This protective gas is vital to the nurturing of life on our planet, and here’s why.
Ozone gases act as a shield against ultra violet, or UVB, radiation. These harmful emissions are sent through the Sun’s rays, and without the ozone would severely affect the planet’s ecological balance, damaging bio-diversity. UVB rays reduce plankton levels in the ocean, subsequently diminishing fish stock. Plant growth would also diminish in turn disrupting agricultural productivity. This would in turn affect the human populace, who would be exposed to an increase in skin-related diseases such as cancer.
So how does the ozone protect us? Ozone molecules consist of three oxygen atoms, hence the chemical formula O3. Stratospheric ozone absorbs UVB high-energy radiation, as well as energetic electrons, which in turn splits the O3 into an 0 atom and an O2 molecule. When the O atom soon encounters another O2 molecule they re-merge and recreate O3. This means that the ozone layer absorbs the UVB without being consumed. The ozone layer absorbs up to 99 per cent of the Sun’s high frequency UV light rays, transforming this into heat after its combustible atomic reaction, therefore creating the stratosphere itself. This effectively incubates life on Earth.
But ozone doesn’t reside only In the world above. This gas is also present in the layer around the Earth’s surface. Ten to 18km above us, this is known as the tropospheric ozone or ‘bad ozone’, comparative to the function of the stratosphere. This ozone occurs naturally in small doses, initiating the removal of hydrocarbons, released by plants and soil, or appearing from small amounts of stratospheric ozone, which occasionally migrate down to the Earth’s surface.
However, it gets a bad reputation due to its interaction of ultraviolet light, with volatile organic compounds and nitrogen oxides, emitted by fossil-fuel powered machines and internal combustion engines. This produces high levels of ozone, which are farmed in high temperature conditions, ultimately toxic to all forms of organic life.
How big is the hole in the ozone layer?
The ozone hole refers to an area of depletion over the Antarctic region of Earth. The planet’s ozone records a decline of four per cent per decade in total volume but much larger loses are recorded in the stratospheric ozone over Earth’s polar region, however this is seasonal condition. These areas’ unique atmospheric conditions see the most impact. Strong winds blow around the continent forming a polar vortex, isolating the air over Antarctica from the rest of the world. This allows special polar stratospheric clouds to form at about 80,000 feet altitude. These concentrate atmosphere pollutant.
When spring returns after the sunless winter period the ozone is depleted causing the ozone hole. The largest ever recorded ozone hole occurred in 2006, at 20.6 million square miles. At present the ozone hole is recorded at between 21 and 24 million square kilometres.