Ozone is a molecule made up of three oxygen atoms which occurs naturally in small quantities.
In the stratosphere, about seven or 25 miles above the Earth’s surface, the ozone layer acts as a sunscreen, protecting the planet from potentially harmful ultraviolet radiation that can cause skin cancer and cataracts, suppress the immune system and even harm plants. .
It is produced in tropical latitudes and distributed all over the world.
Closer to the ground, ozone can also be created by photochemical reactions between the sun and the pollution of vehicle emissions and other sources, forming a harmful smog.
Although warmer than average stratospheric weather conditions have reduced ozone depletion in the past two years, the current ozone hole area is still large compared to the 1980s, when it was first detected depletion of the ozone layer over Antarctica.
In the stratosphere, approximately seven to 25 miles above the Earth’s surface, the ozone layer acts as a sunscreen, protecting the planet from potentially harmful ultraviolet radiation
This is because the levels of substances that deplete the ozone layer such as chlorine and bromine remain high enough to produce a significant loss of ozone.
In the 1970s, it was recognized that chemicals called CFCs, used for example in refrigeration and aerosols, were destroying ozone in the stratosphere.
In 1987, the Montreal Protocol was agreed, which led to the gradual elimination of CFCs and, recently, the first signs of recovery of the Antarctic ozone layer.
The upper stratosphere at lower latitudes also shows clear signs of recovery, showing that the Montreal Protocol works well.
But the new study, published in Chemistry and Atmospheric Physics, found that it is probably not recovering at latitudes between 60 ° N and 60 ° S (London is at 51 ° N).
The cause is uncertain, but the researchers believe that it is possible that climate change is altering the pattern of atmospheric circulation, taking away more ozone from the tropics.
They say another possibility is that short-lived substances (VSLS), which contain chlorine and bromine, could destroy ozone in the lower stratosphere.
VSLS include chemicals used as solvents, paint strippers and degreasing agents.
One is even used in the production of an ozone-friendly substitute for CFCs.