Recently, scientists have observed that a hole over the Arctic Circle's ozone layer has closed. It was a large, massive, and unusual hole that opened up this spring. 

The CAMS or Copernicus' Atmosphere Monitoring Service first took note of the hole early this April, saying that the values of the ozone columns from the area recently attained a record low, with most ozone, found roughly 11 miles up the stratosphere becoming depleted.

It was in the spring of 2011 when the last hole as strong as the current one opened up in the layer. The ozone layer can be found above the stratosphere of the Earth. It functions in absorbing ultra-violet radiation coming from the sun.

However, CAMS tweeted last week how this year's large, "unprecedented" Northern Hemisphere hole mysteriously closed up. CAMS explained that the Polar Vortex has split and had allowed air that is ozone-rich to enter the Arctic. CAMS also added that even if the Polar Vortex has not yet ended and that it might still reform over the coming days, the ozone values in the area are not going to go back to the severely low levels that have been observed in early April.

Scientists from CAMS, however, were quick to point out that the closure of the hole most probably did not have anything at all to do with the plummeting air pollution levels caused by the lockdowns that were spurred by the COVID-19 pandemic. CAMS tweeted that the closing of the hole was instead driven by the unusually persistent and strong Polar Vortex, and is not related to the changes that have been observed in global air quality.

CAMS explains that holes in the ozone are unusual in the Arctic area. However, the situation is different in the Southern Hemisphere. Holes have been developing above the Antarctic every year for the past three and a half decades. These holes are brought about by the accumulation during the winter of chemicals such as bromine and chlorine. They build up within the Polar Vortex and stay in the area.

According to CAMS, they are chemically inactive during winter due to the lack of sunlight. As spring starts, they again become chemically active.

CAMS also explained that usually, the stratosphere over the Antarctic is more isolated than the Arctic due to the latter's nearness to mountain ranges and landmasses, which disturbs weather patterns in the North. This does not happen in the Southern Hemisphere. CAMS further adds that this is the reason why the Northern Hemisphere's Polar Vortex is more perturbed and much weaker than in Antarctica, and why temperatures in the North do not reach such low levels. Nonetheless, CAMS has noted that the 2019's Polar Vortex was among the smallest ones currently on record.

According to Britannica, the ozone naturally occurs in small amounts and forms a layer in the stratosphere of the Earth. The stratosphere is a layer in the planet's atmosphere that occurs between the mesosphere and the troposphere. It contains the ozone layer, which functions in absorbing UV radiation that could otherwise cause severe damage to all living creatures on the planet's surface.