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Transcript of Ozone Depletion
continent form the "polar vortex" This isolates the air over Antarctica from the rest of the world. The sun comes back during spring, when the ozone levels have been severely depleted around the Antarctic continent causing the "ozone hole". Unfortunately, there then follows a particularly long period of high sunshine and long days, which makes the effect of the ozone hole worse. The ozone hole is considered to be wherever the concentration drops below 220 Dobson Units. Every time 1% of the ozone layer is depleted, 2% more UV-B is able to reach the surface of the planet. The EPA estimates that 60 million Americans born by the year 2075 will get skin cancer because of ozone depletion. About one million of these people will die. In addition to cancer, some research shows that a decreased ozone layer will increase rates of malaria and other infectious diseases The most basic microscopic organisms such as plankton would also be effected and may not be able to survive. If that happened, it would mean that all of the other animals that are above plankton in the food chain would also die out. Wind patterns could change, resulting in climatic changes throughout the world. Carpool, bike, or walk instead of driving alone
so less pollutants are released into the air by cars Plant a tree that can supply oxygen for the atmosphere and help “close” the ozone layer a little bit each time. Alternative chemicals and fuels which do
not cause pollution should be invested in to reduce greenhouse gas emission. Recycle paper so that less trees, which release oxygen in to the atmosphere, are cut down Ozone depletion is caused mostly by the release of
chlorofluorocarbons (CFC's), although any pollution that contains chlorine or bromine can have an effect When such chemicals are released into the ozone, they are exposed to UV rays which decompose them, causing the release of chlorine or bromine. These atoms break apart ozone molecules Some of the chemicals that cause this are natural, although most come from man-made pollution In 1978, spray cans containing CFC's were banned in the U.S. After investigation of the Antarctic "ozone hole" in 1985, it became evident that a stronger worldwide response was needed. The Montreal Protocol was signed and many major
nations committed themselves to a reduce in the use of CFCs and other ozone-depleting substances. Over 190 countries have ratified this agreement. For over a decade the production of CFCs have been banned, with some exceptions for essential uses. The next step in the elimination of ozone depleting substances occurred in 2010 when the EPA banned the production of the most harmful HCFCs. The ozone layer is a belt of these naturally occurring gases that exists in the stratosphere However the layer in the stratosphere protects the earth from harmful ultraviolet radiation emitted by the sun There is evidence that the increased levels of pollution of an industrialized world have caused a decrease in the amount of ozone gases present The first large scale evidence of ozone depletion was the measurement of a hole in the ozone layer over Antarctica by Joseph Farman in 1985 Despite learning the cause, CFC's and similar gases, decreases in ozone have since been measured over more populated areas and continue to impact the environment Ozone is a molecule containing 3 oxygen atoms and makes up only 3 out of every 10 million air molecules Ozone that exists in the troposphere can contribute to smog around the earth's surface Naturally, the amount of ozone in the stratosphere is kept at a constant rate by a cycle of reductions and recovery However, man made pollutants have reduced the ozone layer so much, this cycle can't keep up This discovery prompted the signing of the Montreal protocol, a program to encourage research into the causes and effects of depletion, and work to stop harmful emissions 1 chlorine atom can destroy over 100,000 ozone molecules! The EPA is also in charge of many regulating programs made to help the ozone layer and is developing international ozone protection policies to help protect the layer globally.