Реферат: Man And The Ozone Essay Research Paper
Man And The Ozone Essay, Research Paper
Man and the Ozone
Ozone is perhaps one of the singularly most important molecules there is. No, not because man came from ozone, but because it forms a protective layer above the earth in it’s stratosphere which allowed for the growth of life upon land. Before we had an ozone layer, the rays of the sun struck the earth unimpeded, barraging it with the deadly ultraviolet radiation which prohibited any chance of life on earth. However, there was life in the oceans, plant life in particular. This plant life may seem unimportant, especially since it is algae that is being given the spotlight. The algae in the ocean produces oxygen gas (O2), which would rise through the water and up into the “air”, there it would be struck by the ultraviolet radiation, which changed the O2 into O3, which is ozone. This ozone gas has the unique ability to block out the vast majority of sunlight’s harmful ultraviolet radiation. This afforded for the growth of life on the earth’s surface. Despite the ozone layer, which helps block UV light and its radiation, some still gets through and can affect us. First it causes a nice looking tan, or a painful sunburn, however, deeper than that, it is wreaking havoc upon the skin cells, though this damage is cumulative, and is not visible for along time, it does great harm. In fact, ultraviolet radiation is the number one cause of skin cancer, and its occurrence is still rising.
This rise in cases of skin cancer could be linked to a dramatic change in the atmosphere – the loss of ozone. Over the past decades, scientists have begun to study the atmosphere and the ozone layer. They have noticed a marked reduction in the amount of ozone that is protecting the earth from the sun’s harmful UV rays. Before, the amount of ozone in the atmosphere was kept in check by methane gas released from the most mundane of things (like termites). This methane gas would break down small amounts of ozone to keep it from getting to thick, and blocking too much of the suns light, or from causing damage to the animals on land. However, as the scientists’ work has shown, this delicate balance has been disrupted by the pollution produced by man. There are many factors that contribute to the pollution that is destroying the atmosphere, like the byproducts from major industries and manufacturing, of which millions of tons are released into the atmosphere yearly. But the most dangerous pollutant comes form smaller, yet more numerous items: air conditioning units, freezers, refrigerators, aerosol spray cans, and styrofoam products. The one thing which all of theses items have in common is Chloro-Fluorocarbons or CFC’c.
CFC’s are used in all of those products because they are very stable, and non-reactive. That is, they are not flammable, and they will not react with other chemicals. Because they are so stable, CFC’s are not very biodegradable, and thus have a long time to get into the atmosphere and destroy ozone molecules. Once CFC’s reach the atmosphere, they come in contact with ultraviolet radiation that breaks them down and converts them into Chlorine atoms, which in turn react with the ozone molecules. It is estimated that each Chlorine atom is responsible for the destruction of 100,000 molecules of ozone. That is 300,000 oxygen atoms for each atom of Chlorine. This destruction of ozone is most obvious in the north and south poles of the earth, where there has been an estimated 30-40% decrease in ozone levels, and a 100% increase in Chlorine levels. Part of this is due to the unique winter-vortex that is caused by polar winds in the winter, which effectively keep polar air from being recirculated. This air is later released, and goes over Australia and New Zealand, which then experience their highest annual levels of UV radiation.
So why should we be worried about this trend? Well, it is estimated that for every 1% drop in ozone levels there is 10,000 more cases of skin cancer developed in the U.S. alone. This is truly a very costly effect, not only monetarily, but also on peoples emotions and quality of life.
So what is being done to remedy this situation? For one thing, there was a international summit in 1987 which the major world leaders promised to cut CFC production 50% by 1990. Use of CFC’s has doubled instead. More recently, the Environmental Protection Agency (EPA) has passed several accords which serve to limit the number of CFC’s allowed to be produced by various industries annually. If they go over this limit, then they are subject to various penalties and fines. In addition, there have been several vehicle emissions rulings passed which demand lower emissions rating for all newer vehicles.
Although these restrictions are a good idea, it still won’t necessarily cut back on the amount of CFC’s in the atmosphere. The underlying problem is the massive amount of cars being used, and that number is increasing daily. Even with the emission guidelines, the sheer volume of cars in use overpowers all the safe operating levels.
The only way to limit the number of vehicles in use is to promote a inexpensive mass transit alternative. I would propose that local governments set regulations based on state or national guidelines, that would force commuters to use the mass transit system a certain number of times yearly or seasonally.
An example of this plan would be as follows: the city of San Antonio passes an ordinance which states that all working citizens which commute to work, must use the mass transit system X number of days per year. Each working citizen is then issued an electronic ID card that will notify a central computer as to when the commuter uses the mass transit system. To enforce the use, there could be set penalties for failure to comply, or even “rewards” for taking an active part in the pollution control. For a punishment, there could be a fine of 500 dollars (or more depending on required transit use). As a reward however, there could be a minor tax refund, or free mass transit pass (for fares) given to those which use the transit system more than the amount of times required by the city ordinance.
In conclusion, ozone is a very necessary and beneficial component of our atmosphere, which servers to block the harmful UV radiation generated by the sun. This shield, however, is being destroyed at an accelerated rate by pollutants released as a result of man. Mankind needs to limit the amount of pollutants, CFC’s in particular, which it produces in order to protect that which has been protecting us for all of our history.
Environmental Effect of Ozone Depletion:1998 Assessment by United Nations Environmental Programs
Out of the Ozone-video