Write a short note on reflection of depletion of ozone layer
Answers
Ozone depletion describes two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere (the ozone layer), and a much larger springtime decrease in stratospheric ozone around Earth's polar regions.[1] The latter phenomenon is referred to as the ozone hole. There are also springtime polar tropospheric ozone depletion events in addition to these stratospheric events.
External audio
Atmospheric ozone.svg
“Whatever Happened to the Ozone Hole?”, Distillations Podcast Episode 230, April 17, 2018, Science History Institute
The main cause of ozone depletion and the ozone hole is manufactured chemicals, especially manufactured halocarbon refrigerants, solvents, propellants and foam-blowing agents (chlorofluorocarbons (CFCs), HCFCs, halons), referred to as ozone-depleting substances (ODS). These compounds are transported into the stratosphere by tubulent mixing after being emitted from the surface, mixing much faster than the molecules can settle.[2] Once in the stratosphere, they release halogen atoms through photodissociation, which catalyze the breakdown of ozone (O3) into oxygen (O2).[3] Both types of ozone depletion were observed to increase as emissions of halocarbons increased.
Ozone depletion and the ozone hole have generated worldwide concern over increased cancer risks and other negative effects. The ozone layer prevents most harmful UVB wavelengths of ultraviolet light (UV light) from passing through the Earth's atmosphere. These wavelengths cause skin cancer, sunburn and cataracts, which were projected to increase dramatically as a result of thinning ozone, as well as harming plants and animals. These concerns led to the adoption of the Montreal Protocol in 1987, which bans the production of CFCs, halons and other ozone-depleting chemicals.
The ban came into effect in 1989. Ozone levels stabilized by the mid-1990s and began to recover in the 2000s. Recovery is projected to continue over the next century, and the ozone hole is expected to reach pre-1980 levels by around 2075.[4] The Montreal Protocol is considered the most successful international environmental agreement to date.
ANSWER
An ozone molecules (O3) is composed of three atoms of oxygen.Ozone in the upper atmosphere (the stratosphere) is referred to as the "ozone layer" and protect life on Earth by obsorbing most of the ultraviolet (UV) radiation emitted by the sun. Exposure to too much UV radiation is linked to skin cancer, cataracts and depression of the immune system, and may reduce and may reduce the productivity of certain crops. Accordingly, stratospheric ozone is known as "good ozone". In contrast, human industry creates "ozone pollution," at the ground level.This bad ozone is a principal components of smog.The ozone layer is reduced, when man-made CFC molecules (comprised of clorine, flourine and carbon) reach the stratosphere and broken apart by short wave energy from the Sun.