The hole in the Arctic ozone layer, believed to be the biggest reported over the Arctic, has closed. This was because of a phenomenon called the polar vortex, and not due to reduced pollution levels due to Covid-19 lockdowns around the world. The polar vortex is caused by air masses that have cooled down so much they have lost their ability to modify clouds and contain sunlight-causing pollutants. This means that, as proven by CAMS, air pollution has absolutely nothing to do with stopping CFCs or any other ozone-damaging chemicals from entering our atmosphere.
The ozone hole is a region in the lower stratosphere where the concentration of ozone, a type of oxygen molecule, is very low in certain months. During this period, solar UV rays reach levels that are harmful to humans and many other species.
This low-oxygen area is produced each year by the emissions released by humans during the non-attainment of Montreal Protocol targets for anthropogenic ozone depletion. The size of the hole varies according to the seasons and areas affected by sunspots and volcanic activity.
Ozone absorbs the harmful UltraViolet (UV) radiations from the sun eliminating a big threat to life forms on earth. UV rays can cause skin cancer and other diseases and deformities in plants and animals.
Ozone (chemically, a molecule of three oxygen atoms) is found mainly in the upper atmosphere, an area called the stratosphere, between 10 and 50 km from the earth’s surface.
Though it is talked of as a layer, ozone is present in the atmosphere in rather low concentrations. Even at places where this layer is thickest, there are not more than a few molecules of ozone for every million air molecules.
But they perform a very important function. By absorbing the harmful ultraviolet radiations from the sun, the ozone molecules eliminate a big threat to life forms on earth.
Scientists believe that unusual atmospheric conditions, including freezing temperatures in the stratosphere, were responsible for larger Ozone Hole.
As per a European Space Agency report, cold temperatures (below -80°C), sunlight, wind fields and substances such as chlorofluorocarbons (CFCs) were responsible for the degradation of the Arctic ozone layer.
Although Arctic temperatures do not usually fall as low as in Antarctica, this year, powerful winds flowing around the North Pole trapped cold air within what is known as the polar vortex— a circling whirlpool of stratospheric winds.
The hole in the North Pole's ozone layer was first detected in February, 2020 had since reached a maximum extension of around 1 million sq km.