Title: New Culprit Seen in Ozone Depletion
Author: Cornelia Dean
Date Published: August 27, 2009
Source: New York Times
Web Link: http://www.nytimes.com/2009/08/28/science/earth/28nox.html?_r=1&scp=1&sq=ozone%20layer%20depletion&st=cse
Summary: In this article, it talks about how nitrous oxide is an underestimated molecule that ruins the ozone layer. In years past, chemicals like CFC’s were the main causes for ozone depletion, but now that they have been banned from everyday use by the Montreal Protocol, it is becoming clearer that other chemicals also deplete the ozone layer. Nitrous oxide is currently under inspection from the EPA to see if it should be banned from use because of its capability to “trap heat”, which plays a big part in worsening global warming.
Title: Bring Back The Ozone Layer!
Author: Sharon Begley and Mary Hager
Date Published: November 4, 1991
Source: Newsweek
Web Link: http://www.newsweek.com/id/127275
Summary: In this article regarding the phase out of ozone depleting substances, it talks about over 93 countries banning ozone reducing chemicals from the years 1990-2000. Although the phase out was supposed to help the ozone layer, scientists also found that the damage had already been done to the ozone layer and the scientists “have no idea of how bad it could get”. The article also states that because of the weakening ozone layer, the rates of skin cancer has doubled since 1980 and it might possibly get even worse. With the ozone layer getting even worse each year, the time period for recovery gets longer and longer. Already, scientists do not predict the ozone layer to recover until the middle of the 21st century. Even though the depleting ozone layer means more and more UV rays reaching earth, scientists say that since there will not be as many ozone molecules absorbing the UV rays in the stratosphere, it will keep the planet cooler and will help out with global warming. Scientists also say that the earth should be warmer than it currently is because of all the carbon dioxide and other heat-trapping gases that have been used and/or given off in the past 100 years by humans in places like power plants and in cars.
Title: Why is there an ozone hole in the atmosphere, whereas there is too much ozone at ground level? Why doesn't ground level ozone rise to fill the hole in the stratosphere? Why does the ozone up high stay there, and not sink to the ground?
Author: Ross J. Salawitch
Date Published: April 9, 2007
Source: Scientific American
Web Link: http://www.scientificamerican.com/article.cfm?id=experts-ozone-hole-in-atmosphere-not-on-ground
Summary: In this article, Mr. Salawitch talks about how ozone in the troposphere, or the lowest part of the atmosphere, has been given the name “bad ozone” while ozone in the stratosphere is called “good ozone” because of how it blocks ultraviolet radiation given off by the sun. The article also goes on to mention how ozone is naturally produced and destroyed, but the ozone layer is currently “leaking” from all the industrial pollutants that deplete it and help let UV radiation into the troposphere. The amount of ozone in the ozone layer is measured by Dobson units and there can be anywhere around 400 DU’s in the stratosphere on average. CFC’s play a big role in ozone depletion too. After being given off from household items like refrigerators and air conditioners, they will get up into the ozone layer and turn the ozone molecules back into oxygen molecules.
Title: Ozone Hole is Back and Big
Author: Amanda Onion
Date Published: Sep 06, 2001
Source: ABC News
Web Link: http://abcnews.go.com/Technology/story?id=98280&page=1
Summary: Amanda Onion reminds her readers in this article that the ozone hole in the Antarctic region in coming back to reach record size in the year 2001. This region is a perfect place for a huge hole in the ozone layer because of its cold temperatures, the large amounts of man made gases present in the air, and the areas of high and low pressure. Not only is there a hole over Antarctica, but above Chile there is also a growing hole. Scientists at NASA advised Chileans in September of 2000 to protect and shelter themselves from the growing ozone hole above the country. Although the Antarctic hole has reached record sizes in 2000 and 2001, Scientists think that it will disappear around 2040.
Title: Report: Antarctic Ozone Hole as Big as It's Ever Been
Author: Associated Press
Date Published: October 3, 2006
Source: Fox News
Web Link: http://www.foxnews.com/story/0,2933,217498,00.html
Summary: According to Fox News, in 2006 the ozone hole has reached a record setting size. Scientists at NASA were claiming that in 2006 there was the least amount of ozone particles in the ozone layer since 2000, which was another year that the hole was at a record high size. The ultraviolet radiation that will reach earth’s surface because of the ozone hole will harm both humans and animals at the bottom of the food chain. According to the scientist’s studies, the ozone hole seems to enlarge and thrive in the Antarctic winter months, especially September. Scientists at NASA also predict that the hole will not close and the ozone layer will not completely improve and recover until 2065, which is 15 years longer than they previously predicted.
Showing posts with label ozone. Show all posts
Showing posts with label ozone. Show all posts
Tuesday, May 25, 2010
Sunday, May 16, 2010
The Science Behind The Ozone Layer
-An Ozone molecule, which is also called trioxygen (O3), consists of three oxygen atoms and comes in the form of a bent molecule (similar to a water molecule). Ozone is made from the reaction of ultraviolet radiation from the sun and oxygen in the stratosphere. To start the reaction, UV radiation breaks apart a diatomic oxygen molecule. After the two oxygen atoms are separated apart, they go and bond with other O2 molecules to create a new ozone molecule (O2). The reaction is shown below:
O2 + (solar energy/ UV Radiation) → O + O2 → O3
-Ozone has a boiling point of -112 ° C, a melting point of −192.5 °C, and is considered a less stable allotrope of the diatomic O2. According to the the U.S. Environmental Protection Agency, a single atom of chlorine can destroy more than a hundred thousand ozone molecules. Along with chlorine, bromine, nitrogen, hydrogen, and oxygen gases also destroy ozone molecules. Ozone is considered to be a dangerous chemical and air pollutant when found in the lower atmosphere (below the stratosphere) because of the many negative effects it has on plants and animals. In animals, it can damage the respiratory system and also has many of the same effects it has on humans while in plants, it burns and kills the plant's cells.
-The ozone layer is found in the stratosphere, which is above the troposphere (the lowest region of the atmosphere) from 15-30 kilometers above sea level. About 90% of all of the worlds ozone can be found in the stratosphere. The ozone layer's main job is to prevent as much ultraviolet radiation from entering the troposphere and lower atmosphere as possible. The ozone layer blocks anywhere from 97-99% of the utlaviolet light given off from the sun In recent years past, we have used products that only deplete and reduce the amount of ozone in the ozone layer. Since there is not as much ozone to block the UV rays, more and more UV rays are entering the lower atmosphere and are harming humans. The artic circle is where the ozone layer is most depleted. The cold temperatures there speed up the breaking down of ozone molecules when certain chemicals come into contact with the ozone. In the winter of 1999-2000, the ozone layer over the artic circle lost over 60% of its ozone and is currently rebuilding, but scientists say that it will take decades for the ozone layer to rebound there. One chemical that has been used a lot that harms the ozone layer is dichlorodifluoromethane (CFC-12), which consists on chlorine, flourine, carbon atoms and otherwise known as freon-12. This chemical has been a significant part of most air conditioners, refrigerators, and aerosol spray products. Although it was a significant component of most of the products listed above, it has been banned more than ten years ago by the environmental protection agency and is not used any more. Along with banning CFC-12, the epa has also banned many other substance that they claim and have classified as ozone depleting substances.
O2 + (solar energy/ UV Radiation) → O + O2 → O3
-Ozone has a boiling point of -112 ° C, a melting point of −192.5 °C, and is considered a less stable allotrope of the diatomic O2. According to the the U.S. Environmental Protection Agency, a single atom of chlorine can destroy more than a hundred thousand ozone molecules. Along with chlorine, bromine, nitrogen, hydrogen, and oxygen gases also destroy ozone molecules. Ozone is considered to be a dangerous chemical and air pollutant when found in the lower atmosphere (below the stratosphere) because of the many negative effects it has on plants and animals. In animals, it can damage the respiratory system and also has many of the same effects it has on humans while in plants, it burns and kills the plant's cells.
-The ozone layer is found in the stratosphere, which is above the troposphere (the lowest region of the atmosphere) from 15-30 kilometers above sea level. About 90% of all of the worlds ozone can be found in the stratosphere. The ozone layer's main job is to prevent as much ultraviolet radiation from entering the troposphere and lower atmosphere as possible. The ozone layer blocks anywhere from 97-99% of the utlaviolet light given off from the sun In recent years past, we have used products that only deplete and reduce the amount of ozone in the ozone layer. Since there is not as much ozone to block the UV rays, more and more UV rays are entering the lower atmosphere and are harming humans. The artic circle is where the ozone layer is most depleted. The cold temperatures there speed up the breaking down of ozone molecules when certain chemicals come into contact with the ozone. In the winter of 1999-2000, the ozone layer over the artic circle lost over 60% of its ozone and is currently rebuilding, but scientists say that it will take decades for the ozone layer to rebound there. One chemical that has been used a lot that harms the ozone layer is dichlorodifluoromethane (CFC-12), which consists on chlorine, flourine, carbon atoms and otherwise known as freon-12. This chemical has been a significant part of most air conditioners, refrigerators, and aerosol spray products. Although it was a significant component of most of the products listed above, it has been banned more than ten years ago by the environmental protection agency and is not used any more. Along with banning CFC-12, the epa has also banned many other substance that they claim and have classified as ozone depleting substances.
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