Here in Southeast Asia it often gets hot enough to fry an egg on the pavement. Imagine if the sole protection we have from the sun’s nuclear energy disappeared — the ozone layer.
What Is the Ozone Layer?
Ozone (O3) is a pale blue gas with a pungent smell, the molecules of which consist of three oxygen atoms each. We have all smelt ozone in the scent before a storm arrives when lightning breaks down molecules containing oxygen atoms which then recombine into ozone.
Located in the Earth’s stratosphere, the ozone layer is about 20 to 30 kilometres above the surface and acts as a shield, absorbing and reflecting ultraviolet (UV) radiation which is harmful to animals, plants and bacteria alike.
For us humans UV radiation can cause lethal or debilitating health problems, such as skin cancer — melanoma and non-melanoma — as well as eye conditions like cataracts.
Without the ozone layer to protect us, life on this planet would be under constant bombardment from this dangerous radiation emanating from the sun.
Ozone is destroyed by ozone-depleting substances (ODS) which include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), methyl bromide and carbon tetrachloride, amongst others.
These compounds are used in industrial solvents, pesticides, refrigeration, packaging, fire extinguishers, insulation and other applications.
ODS are extremely hardy and do not break down in Earth’s lower atmosphere. They are insoluble in water. In fact, there is no natural way to get rid of them.
Eventually the ODS make their way into the stratosphere where, on exposure to UV light, they break down, releasing chlorine or bromine, both of which are extremely efficient at destroying ozone.
A single chlorine atom destroys about 100,000 ozone molecules. Bromine is even more efficient, although thankfully there are much fewer bromine-based ODS in the stratosphere.
The worst part is that CFCs and HCFCs are entirely man made. They do not exist in nature. All of the damage to the ozone layer is caused by we humans.
International treaties, such as the Montreal Protocol which planned the phasing out of CFCs and HCFCs in developed countries, have helped the ozone hole over the Antarctic to recover.
What You Can Do
These are a few of the steps you can take towards helping conserve and protect the invisible shield that allows life on Earth to flourish:
- Do not buy aerosols which use CFCs — check the label or use pump sprays to be sure they contain no CFCs.
- Check if your fire extinguishers contain halon or halogenated hydrocarbon — if they do, replace them with ones which do not use ODS.
- Drive less — nitrous oxide is the biggest ODS in the atmosphere and is found in car exhaust. Walking, public transport, carpooling and cycling are all better options.
- Dispose of old air conditioners and refrigerators properly — they rely on CFCs to function. Newer models should be CFC-free but check to make sure.
- Buy wood or wood products that are not treated with methyl bromide — they give off bromine gas which enters the stratosphere. Look for the MB mark and avoid it.
It is up to us to rectify the mistakes we have made in the past and ensure the ozone layer recovers, not just for the our own and our families’ sake, but for the entire planet.