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Essay Subject: Composition, location, dangers of chloroflourocarbons & aerosols, possibility of reducing emissions, recovery & recycling.... More...

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Paper Abstract: Composition, location, dangers of chloroflourocarbons & aerosols, possibility of reducing emissions, recovery & recycling. Paper Introduction: In 1985, British scientists discovered a hole, the size of the United States, in the ozone layer; the hole had been occurring over Antarctica each spring since 1979 (World watch Paper 87). Although the theory said that a group of widely used chemicals called chloroflourocarbons (CFC's) would someday evade the upper atmosphere ozone, none of the models predicted it would be over the South Pole or that it would be so severe. Also during this period, the expected rate of the greenhouse warming accelerated because its relationship to CFC's became clearer to scientists (Miller and Mintzer). In the fall of 1986, the U.S. and European users and producers of CFC's and DuPont Chemicals, the largest single CFC manufacturer, endorsed limits on CFC production (Miller and Mintzer). Government decisions concerning Ozone depletion will influence the greenhouse problem, the Text of the Paper: The entire text of the paper is shown below. However, the text is somewhat scrambled. We want to give you as much information as we possibly can about our papers and essays, but we cannot give them away for free. In the text below you will find that while disordered, many of the phrases are essentially intact. From this text you will be able to get a solid sense of the writing style, the concepts addressed, and the sources used in the research paper. (1) Increasing Efficiency and Reducing Operating Losses.In some CFC applications, leakage represents a large share of totalproduction. Some of these can besubstituted without a change in the existing equipment, though at a costseveral times as great as CFC-11 or 12 (Miller and Mintzer). CFC's contribute to the greenhouse effect as well as tothe changes predicted in the distribution of ozone (Miller and Mintzer).The discovery of the hole over Antarctica prompted 35 countries to sign aninternational agreement - the Montreal Protocol - which is aimed at tryingto halve most CFC emissions by 1998.Make-up of the Ozone Layer Ozone is formed in the stratosphere when ultra-violet radiationbreaks diatomic molecules of oxygen. This rise in production cost would definitely bereflected in the retail price of the product using the substitute.Therefore, these options will not be chosen unless governments createincentives for manufacturers or unless consumers demand the substitute("Europeans" 32A). However, leakage will occur during disposalunless the material is buried or burned, which would prevent the release ofCFC's in the stratosphere. "Chlorofluorocarbons in the Environment." England: Market Cross House, 198 ."In Protecting the Atmosphere, Choices Are Costly and Complex." The New York Times.Miller, Alan and Irving Mintzer. Recovery is possible for processes with in-housedistillation equipment that boils off, condenses, and collects the solventfor re-use. The amount of CFC's used in refrigeratorsdepend on the type of compressor used: reciprocating compressors use onlyone-third to one-half of refrigerant that rotary compresses do (Miller andMintzer). The United States and several other countrieshave substituted hydrocarbon propellants for more than 9 percent ofaerosols (Miller and Mintzer). The replacements cost at least threetimes more to produce, they are less effective, and they need to bereplaced sooner. Substituting technologies are emerging for some other uses.For example, experimental vacuum panels developed for insulatingrefrigerators can out-perform rigid foams made with CFC's (Miller andMintzer). Product substitutes exist for most CFC uses, though often someeconomic or performance loss is involved and sometimes a health or safetyrisk (Miller and Mintzer). Once split, two oxygen atoms combinewith two molecules of diatomic oxygen to form ozone. Almost all the CFC-11 used to manufacture flexible foams islost during production. The mostwidely known of this form of CFC is Styrofoam. manufacturer of CFC'S, announced in September1986 that it could produce substitute CFC's in large quantities in fiveyears, given adequate incentives (World Watch Paper 87). However, differences in location and organization ofthe CFC industry and limitations of the use of hydrocarbons prevent globalsuccess of this method (Miller and Mintzer). Ithas also made more comfortable living conditions for residents in warmclimates. Methods of CFC reduction by recovering the compound and by cleaningthe chemical for release are feasible and are in use today (Miller andMintzer). Most chemicals in theatmosphere have lifespans of a few weeks or a few months, but because ofthe chemical stability of the CFC'S, they can last for a century or more.This same stability allows them to reach the stratosphere, 15-5 km abovethe earth. As more ultraviolet radiation penetrates the atmosphere, thesehealth effects will worsen, there will be a reduction in crop yields andfish population, damage to some materials (such as plastics) and anincrease in smog. Many technological developments were assisted by CFC'S. For example, because of fireregulations, Japan prohibits the use of hydrocarbons in cosmetics sold inJapan. Leakage in the air conditioners can be reduced by redesigning theequipment to reduce the number of joints and by using caution whentightening and sealing valves. Leakage in rigid foams is not really considered a problem, especiallyif the material is enclosed. Here the liquid form of CFC-12 is vaporizedinto a gas that forms lightweight closed cell bubbles (Horwood). "The Sky Is The Limit: Strategies For Protecting the Ozone Layer." World Resources Institute (November 1986).World Watch Paper 87. This chemical is also versatile enough to beused on plastics and metal and even as a dry-cleaning solvent. Chlorofluorocarbons were first produced in the early 193 's, becausea safe (non-toxic) coolant was needed for refrigeration. (4) Substitution of non-CFC products. Foamemissions may be glacially slow. Reilly, head of the Environmental ProtectionAgency, cautioned that care was needed in finding substitutes for thechlorofluorocarbon compounds: "We need to be sure," he said, that any CFCsubstitutes that might be developed do not pose new and unforeseenenvironmental risks, such as exacerbating global warming ("In Protecting"). "Stones in a Glass House: CFC's and Ozone Depletion. But by the 195 'sthere was a high boost in CFC production. Another use for the chemicals CFC-11 and CFC-12 is as a blowing agentdiscovered in the late 194 's. Most of the Ozone is foundin the stratosphere anywhere from 6 to 3 miles above earth. Following the energy crisesof the 197 's, industrial, commercial, and residential customers looked fornew ways to decrease their heating and electric bills. Stationery refrigerators and airconditioners use methods that generally leak less than non-stationarysystems. U.S. CFC's are stored until the foam iscrushed; large amounts of CFC's are essentially "banked for the future"unless release is prevented. However, this is a good methodfor CFC-113, the solvent. But it can be recaptured and recycled through acarbon filtration system that will also reduce operating losses by 5 percent (Miller and Mintzer). CFC's can be recycledfor vehicle air conditioning systems, but it would only become economicallyattractive if the price of CFC-12 rises. The net result is areduction in the ozone concentration (Miller and Mintzer). The economics andpracticality of the recycling method is too great a barrier for use insmall operations like automobile air conditioning. Continued ozone depletion will affect everyone on thisplanet. The concentrations of ozone at differentaltitudes also affect temperature, air movements, and the downward emissionof infrared radiation, which in turn influences the radiative andmeteorological processes that determine the climate (Miller and Mintzer).Therefore, if the amount of ozone in the environment changes significantly,major environmental consequences could result, among them a greenhousewarming. Some forms of CFC's present little or no threat to the ozone layer.Several of these formulations could substitute for CFC-11 and CFC-12,greatly reducing the threat to the ozone layer. The form of CFC used in refrigerants and cooling mechanisms is CFC-12. Washington, D.C.: Investor Responsibility Research Center, 1988."Europeans to phase out chlorofluorocarbons." San Jose Mercury News 3 March 1989: 32A.Horwood, E. This is because of theirexceptional balance of properties: nonflammatory, lack of color, extremestability, low toxicity, solvent power, range and stability for vaporpressures, thermodynamic characteristics and ease of manufacture (Horwood). The rest is emitted when the unit is first manufactured or when it isdisposed of. This brought out astrong demand for rigid foam insulation. It is here that the intense ultraviolet radiation causes theozone to break its bonds, releasing the chlorine atom. Ozone concentration varies with altitude. CFC-113 iscurrently the fastest growing CFC in (usage) production (Miller andMintzer). William K. CFC-113 is used as a solvent to remove glue, grease, and otherresidues from computer chips. In the fall of 1986, the U.S. Huge airconditioners made it possible to build malls and tall office buildings. However, aerosols with CFC as apropellant are only in 4 percent use in Europe and 1 percent use in theUnited States (Horwood).Solutions - Reduction of Emissions All of the processed waste of the CFC's are very necessary becausethe emissions of the products release them into the atmosphere (Miller andMintzer). Despite the availability of information concerning the cost and thefeasibility of substitutes for many uses of CFC'S, assessing the total costand feasibility of methods for reducing CFC emissions is difficult.Potential replacements for CFC chemicals are now used extensively asrefrigerants and as propellants. Technology andstricter standards set on the production and on the use of CFC's couldreduce emission of them. They are also popular for their longevity. Appliance manufacturers also usedit to boost the energy efficiency of refrigerators using foam walls(Cogan).Aerosols Aerosols are the most widely used CFC's because of their availabilityto the public. They create emissionsvirtually immediately after use. DuPontChemicals, the largest U.S. The availabilityof safe CFC's that can be substituted without radical changes in existingequipment represents a major step toward reducing risks to the ozone layer. Itis because aerosols emit CFC's directly into the atmosphere that they areconsidered the worst chlorofluorocarbons. When the product (e.g. To keep the ozone-oxygen balance in the atmosphere, ozone molecules are also broken apart byultraviolet rays into oxygen, oxygen, and ozone in the stratosphere.However, reactions between ozone molecules and chlorine, nitrogen, andbromine oxides can upset the chemical balance and reduce the amount ofozone (ozone depletion) (Miller and Mintzer). In 1985, British scientists discovered a hole, the size of the UnitedStates, in the ozone layer; the hole had been occurring over Antarcticaeach spring since 1979 (World watch Paper 87). For insulation, several product substitutions are available.Cardboard packaging now competes with some foams (polystrene), and severalinsulating materials, without CFC'S, are made, such as fiberglass andcellulose. For example, almost one-third of the CFC used in the UnitedStates is for automobile air conditioning, of which an estimated 3 percentis lost in leakage or while the car is being serviced (Miller and Mintzer). Ozone absorbsmuch of the ultraviolet radiation that the sun emits in wavelengths harmfulto humans and animals (UV-B). These approaches are primarily used in operations large enoughto justify the cost of necessary additional equipment. Reduction of emissionsof CFC's can occur in four basic ways: (1) redoing operating losses; (2)recovering and recycling during production or at the point of use; (3)substituting CFC formulations less threatening to the stratosphere; and (4)switching to processes or products that require no CFC's (Miller andMintzer). hairspray) is expelled, the CFC's thatare acting as the propellant are released into the atmosphere as well. In order to curb the amounts of CFC'sreleased in the environment, there must be a total halt in the emission ofthe CFC, and replacements must be made available. The chlorine reactswith the oxygen, nitrogen, and hydrogen oxides. As the ozone diminishes inthe upper atmosphere, the earth receives more ultraviolet radiation, whichpromotes skin cancers and cataracts and depresses the human immunitysystem. authorities consider the substitutionhighly successful. Although the theory saidthat a group of widely used chemicals called chloroflourocarbons (CFC's)would someday evade the upper atmosphere ozone, none of the modelspredicted it would be over the South Pole or that it would be so severe.Also during this period, the expected rate of the greenhouse warmingaccelerated because its relationship to CFC's became clearer to scientists(Miller and Mintzer). In 1974, scientists discovered the basic link between CFC'S, ozonedepletion, and the greenhouse effect (Miller and Mintzer). Works CitedCogan, Douglas G. Protecting Life on Earth: Steps to Save the Ozone Layer (December 1988).----------------------- 1 In refrigerants the CFC's are usually enclosed in a tube andonly leak out with old age and with the destruction of the tube. In vehicular systems, the technical problems are morecomplicated, and the price of CFC's is not high enough so that theconsumers would initiate a change. (3) Safe CFC (other mixtures). and European users andproducers of CFC's and DuPont Chemicals, the largest single CFCmanufacturer, endorsed limits on CFC production (Miller and Mintzer).Government decisions concerning Ozone depletion will influence thegreenhouse problem, the warming of the earth as heat-trapping gases buildin the atmosphere. These samecharacteristics are ideal for the uses to which they are put.Chlorofluorocarbons are used as working fluids in refrigeration and airconditioning units, as a solvent used for cleaning computer hardware, as apropellant in the use of aerosols, and as blowing agent in the rigid andflexible foams that are used in energy conservation (Horwood). Aerosol sprays are on display in most grocery stores, andthey can be found in almost all homes. An industry definition of anaerosol is "an integral ready-use package incorporating a valve and aproduct which is dispensed by pre-stored pressure in a controlled mannerwhen the valve is operated" (Horwood). The pre-stored pressure is called apropellant, and the function of a CFC in an aerosol is to act as thepropellant. Most products emit gradually, but aerosolsare the worst offenders in the expulsion of CFC. (2) Recovery and Recycling. If this paper is not what you are looking for, you can search again: Search for: or Click here to request an essay written just for you.

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