On 24 August 2022, National Oceanic and Atmospheric Administration (NOAA) announced that the concentration of ozone-depleting substances in the atmosphere had fallen just over 50% back to levels observed in 1980. According to an annual analysis of air samples collected worldwide, NOAA scientists discovered a continued decline in the atmospheric concentration of the ozone-depleting substance in the mid-latitude stratosphere.
In the 1980s, the scientific community discovered that a class of man-made chemicals was seriously damaging this protective ozone layer, creating a giant “hole” in the ozone layer over Antarctica and smaller, but still worrisome depletion in mid-latitudes. As part of the US response, Congress mandated that NASA and NOAA monitor stratospheric ozone and ozone-depleting substances in the 1990 amendments to the Clean Air Act. The Ozone Depleting Gas Index is one way that NOAA fulfills this mandate.
Scientists at NOAA’s Global Monitoring Laboratory created the index to render the results of a series of complex analyses into a single number that tracks the total abundance of these chemicals and how the threat they pose to the ozone layer is changing over time. The year 1980 was selected as the benchmark year for the index because scientific and policy communities have
“It’s great to see this progress,” said Stephen Montzka, senior scientist for NOAA’s Global Monitoring Laboratory. “At the same time, it’s a bit humbling to realize that science is still a long way from being able to claim that the issue of ozone depletion is behind us.”
Check out NOAA’s announcement for more information!
What is Ozone?
The molecule formed by the combination of 3 oxygen atoms is called ozone. Ozone is a Greek word meaning smell. It is a gas that smells heavy and offensive and destroys the respiratory tract. It is these ozone molecules that give the sky its blue color.
What is the Ozone Layer?
Ozone exists in two different places in the atmosphere. The first is the stratosphere, and the second is the troposphere. The ozone layer, located between 19-45 km of the stratosphere, is called the ozonosphere. Ozone in the ozonosphere help reflects harmful rays from the sun. However, the reason for the ozone accumulation in the troposphere is that toxic chemicals released by humans into the air react to form ozone.
The Depletion of the Ozone Layer
The depletion of the ozone layer, which we also hear as the depletion of the ozone layer, was a severe threat to our world until the last 30 years. Because the earth’s temperature was increasing, serious ice melt was observed at the poles, and it was said that the reason for this was the thinning of the ozone layer. The ozone layer is essential for all living things and our world. Still, in recent years, especially with the ban on the use of the chemical we called chlorofluorocarbon in 1987, it has been observed that the thinning of the ozone layer has stopped. Even the layer has repaired and thickened itself. So, what are the chemicals that cause ozone layer depletion? The first is the gases used in refrigerators, air conditioners, and foam production, which we know as chlorofluorocarbon (CFC). The damage caused by CFC gases was not noticed until the 1970s. After it was caught, the use of CFCs was banned worldwide with the Montreal Protocol in 1987.
Other substances that cause ozone decomposition include hydroxyl (OH-), nitrogen monoxide (NO), chlorine (Cl), and bromine (Br). As a result of these substances mixing with the atmosphere, the ozone layer is damaged.
The thinning of the ozone layer is mainly observed at the south pole. This is because chemical reactions are more effective at the poles. High levels of chlorine and bromine ions due to low temperatures cause more damage to the ozone layer than in other parts of the world.
The thinning of the ozone layer can cause skin cancer, cataracts, and immune system diseases due to the increase in UV rays falling on the earth. It also harms animal and plant species.