CFCs, also known as chlorofluorocarbons, are a group of compounds that contain carbon, chlorine, fluorine, and occasionally hydrogen atoms. Before the creation of CFCs, refrigeration systems, as well as air conditioning systems, relied heavily on other highly flammable and toxic compounds making them a hazard to the public. Compounds used during this period included chemicals such as ammonia, chloromethane, propane, sulfur dioxide, and many others; this could cause serious injury and damage. Then, in 1928, an American named Thomas Midgley, with the help of his team completed the creation of CFCs to be used in place of harmful chemicals in refrigeration and air conditioning systems. The advantage of CFCs over previously used chemicals is that they are non-flammable and are not toxic to humans. As awareness that CFCs were a safe replacement for other chemicals became more widespread, CFCs began to be mass-produced around the world and were applied in many other systems such as foam blowing, aerosols, and cosmetics. By the 1970s, CFCs were used in manufacturing worldwide with an estimated nearly one million tons produced per year. Due to the high production and use capacity of CFCs, they were emitted into our atmosphere in large quantities, compromising the condition of the ozone layer. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay The ozone layer is a layer surrounding the Earth high in the atmosphere. It is found specifically in the stratosphere and troposphere and is estimated to be 10-30 kilometers above the Earth's surface. The ozone layer is essential for life on earth as it protects all living things from the sun's harmful ultraviolet rays. The ozone layer filters and absorbs much of the radiation that protects the Earth's surface from high exposure to UV rays. This is crucial because studies have shown that plants, animals and humans are subject to harmful effects when exposed to large amounts of radiation. The ozone layer contains significant amounts of ozone which is a special type of oxygen; they are three oxygen atoms bonded together (O3). Ozone is a rare chemical present in our atmosphere, but it plays a very important role that makes the destruction of the ozone layer by CFCs even more concerning. When CFCs are at sea level, they are very stable compounds and do not react highly. But as they begin to move upward and find themselves in the atmosphere, ultraviolet radiation emitted by the sun breaks down the compound and separates a chlorine atom. Once this occurs, the highly unstable chlorine atom containing an unpaired electron will be free in the atmosphere. The single chlorine atom will then split the ozone molecules to try to combine with a single oxygen molecule to create a stable compound; chlorine monoxide. A single chlorine atom can react and destroy up to 100,000 ozone molecules before finally binding to one of them, which is why small amounts of CFCs can have such a large impact on the ozone layer. Furthermore, once a chlorine molecule has stabilized with an oxygen molecule, UV rays will simply break it down again creating a nearly infinite cycle. Even since the use of CFCs was stopped internationally, CFCs have already destroyed the ozone layer in the past, making it thinner and weaker around the world. But it has had a particularly large impact on the Arctic and Antarctic regions since thelower temperatures cause the chlorine atom to break down from the CFC more rapidly than in warmer climates. The use of CFCs in the past has made ozone weaker overall and less effective at filtering and absorbing harmful UV rays. During the 1970s scientists Paul Crutzen, Mario Molina and Sherwood Rowland raised concerns about the effects of CFCs on the ozone layer. And in 1978, ozone depletion was a topic of major public conversation. They were concerned about large CFC emissions over the years that could cause a catastrophe in the ozone layer. Despite the concerns, nothing was identified in the ozone layer during this period to suggest anything was wrong and the layer appeared normal. A scientist from the British Antarctic Survey began monitoring the ozone layer and soon discovered that ozone values ​​had declined in several regions of the world since the 1970s. In 1981, scientists could tell there was something wrong with the ozone layer, but they couldn't pinpoint the exact problem. Then, one day in 1984, scientists discovered a large hole in the ozone layer over Antarctica that seemed to appear out of nowhere in their data. Of the two research teams stationed in the region, scientists from the British Antarctic Survey were the first to discover the baffling hole and share it with the public. Despite this, many still didn't know what to make of the hole; they thought it might be a malfunction or error in the systems. Then, in late 1984, scientists at NASA and around the world gathered more data about the ozone hole and its causes. Therefore, the hole in the ozone layer was confirmed as real. As stated earlier, the ozone layer plays a huge role in life on earth. The depletion of the ozone layer, especially in the Antarctic region, where the ozone hole is located, has allowed more UVB radiation to enter through the Earth's atmosphere. This has caused multiple environmental and health problems. As for health concerns, increased exposure to UV rays has been scientifically proven to cause various health conditions in humans, such as increased risk of skin cancer, eye damage, and impaired immune system. By way of comparison, before the 1980s, sunscreen was not worn heavily by the public as the ozone layer was strong and filtered out most harmful UV rays. But currently, if we go out without sunscreen, we are very likely to end up with a sunburn as the UV index is much higher due to ozone depletion. Furthermore, increased UV rays have affected the growth of plants and phytoplankton, and since they are the producers of almost every food chain, it greatly affects a large number of ecosystems. Once scientists discovered the effects of CFCs on the ozone layer, everyone quickly came to agreement that they needed to be stopped. Therefore, in 1987, an international agreement was signed, called the Montreal Protocol, which began the phase-out of all chemicals that damage the ozone layer, including CFCs. This protocol helped control the damage done to the ozone layer and continues to protect the layer as it recovers to this day. Scientific studies and monitoring of the ozone layer confirm that it is recovering and estimate that it should return to its original state by 2040. In 1974, scientists Drs. F. Sherwood Rowland and Mario Molina. They believed that CFCs were capable of rising into the stratosphere where they would break down, release a chlorine atom, and damage ozone molecules. However, when they introduced 2040.