Ozone Layer The Harmful Uv B Radiation example essay topic

OzoneOzone (O3) is a molecule consisting of three oxygen atoms, similar to the oxygenwe breathe (O2), however oxygen consists of only two oxygen atoms. In thestratosphere, a region high up in the upper atmosphere, light rays areresponsible for the breaking down of oxygen (O2), breathable oxygen into its twoseparate oxygen atoms. Lone oxygen atoms are markedly reactive. When a loneoxygen atom comes into contact with a breathable oxygen molecule (O2) itcombines to form ozone (O3).

The ozone layer is a small residual amount ofozone concentrated in a band in the upper atmosphere. This band of concentratedozone resides approximately between twenty and forty kilometers high in thestratosphere. The ozone layer reactions that both create and destroy ozone hascome into a dynamic equilibrium. This dynamic equilibrium is very delicate andresulted during atmospheric formation (Environment Canada, 1996). Ozone, however,is very rare even in the ozone layer. Oxygen makes up approximately twentypercent of air and ozone makes up only 3 x 10-5 percent of air.

Furthermore,this minuscule amount of ozone is enough to protect the earth from mostultraviolet light. Ozone prevents most UV-B radiation from reaching the surfaceof the earth (Environment Canada, 1996). Ozone is very important to life onearth because the harmfulness of high-energy UV-B radiation stems from the highenergy of these light rays, enabling them to penetrate deeply into water, planttissue and epidermal tissue of animals. Increased UV-B radiation results inharming the metabolic system of cells and ultimately damage to genetic materialpresent in effected cells. Living organisms on the surface of the earth havealways been exposed to some, and only slightly differing levels of UV-Bradiation depending of geographic location and season.

Through evolution,cellular repair mechanisms have evolved to safeguard cells against damage doneby UV-B radiation. With the increase in the UV-B radiation, more damage is doneto cellular functions then the natural protection system can deal with (Environment Canada, 1996). Life on earth would more or less be void if not forthe formation of the ozone layer during atmospheric formation (Porter, 1996). With out the ozone layer the harmful UV-B radiation would not allow the growthof autotrophic plants, resulting in reduction in oxygen production; ultimatelythe destruction of most living organisms on the earth surface would result. Increased UV-B radiation has been linked to many incidence of increased healthproblems among humans. UV-B radiation leads to increase skin cancer, eye damage,and possible inhibition of the immune system (Health Canada).

These incidencehave been noticed in humans, and it is presumed that these problems will occurin other animals as well. Terrestrial plant life is of great vulnerability toincreased UV-B radiation, it can cause the destruction of chlorophyll in plantleaves resulting is less growth, and ultimately reduction in crop yields, forestannual increments and a general decline in forest ecosystem health. The UV-Bradiation also causes the potential for the decrease in the populations ofphytoplankton in the world's oceans, causing yet more problems when one analyzesphytoplankton in the oceans food chain (Clair, 1996). Humans are responsible foralmost all activities and pollutants that deplete the ozone layer.

Humanity hasdamaged the ozone layer by adding synthetically made molecules containing bothchlorine and / or bromine to the atmosphere. Both chlorine and bromine areattributed to ozone destruction. The most commonly know group of these arecalled CFCs, chlorofluorocarbons. Chlorofluorocarbons are utilized for manyindustrial and domestic applications. At the earth surface, these moleculesremain stable. However, with their release into the atmosphere they aresubject to global air currents, winds aloft and atmospheric mixing, causing themto drift up into the stratosphere.

Other chemicals such as halons, carbontetrachloride and methyl chloroform, also attribute to ozone depletion. Howeversome naturally found molecules in the stratosphere, such as nitrous oxide, alsoa by product of the burning of fossil fuels, attribute to the break down ofozone (O3). Natural factors include the quasi-biennial oscillation ofstratospheric winds which occurs approximately once every 2.3 years, and the 11year sunspot cycle. However the observation of the sunspot cycle reveals thatthe total global ozone levels should not decrease more than one to two percent (Environment Canada, 1996). In the stratosphere such molecules are effected byenergetic UV-C radiation. UV-C radiation breaks down chlorine, freeing an atomof chlorine (Cl).

Chlorine atoms will react with ozone (O3) by splitting of oneoxygen atom to form Chlorine oxide (ClO) and Oxygen (O2). The Chlorine oxidehowever will again be broken down into Chlorine and a free oxygen atom to allowthe chlorine to continue destroying ozone. One Chlorine atom (Cl) can destroyten thousand ozone molecules (Environment Canada, 1996). With the identificationof the human-produced chemicals that have lead to the destruction of the ozonelayer the extent of the threat to stratospheric ozone has been realized. Withthe emergence of the scientific evidence on the ozone depletion threat, theinternational community agreed to regulate ozone destructive chemicals, andsetup a timetable for their complete phase-out. The 1987 Montreal Protocol, andsubsequent London 1990, and Copenhagen 1992 amendments was an agreement thatstipulated this timetable.

The Montreal Protocol was a monumental achievementin international environmental cooperation and protection. The Protocol allowedfor the refinement of the timetable as the on-going process of scientificunderstanding on ozone depletion improved, the phase-outs cloud be expedited. In the spring of 1989, eighty countries met in Helsinki, Finland to assess newinformation. Unanimous agreement to a five point 'Helsinki Declaration'.

TheDeclaration stipulated that all countries join both the Vienna convention forthe protection of the ozone layer and the Montreal Protocol, phase out of CFCsby 2000, phase out halons as soon as feasible, commit to the development ofalternative environmentally acceptable chemicals and technologies, and makeinformation accessible to developing countries. In 1995, over one hundred andfifty countries had ratified the Montreal Protocol. In compliance,chlorofluorocarbons, carbon tetrachloride and methyl chloroform production wasto be phased out at the end of 1995; methyl bromide is currently scheduled forUnited States phase-out by 2001; and all hydorchlorofluorocarbons will be phasedout by 2030 (Environment Canada, 1993). Environment Canada has implemented a UVindex to provide information to the general public on specific UV hazards daily. Constant monitoring, global awareness and the eventual phase-out of all ozonedepleting substances are all part of Canada's measures for the protection of theozone layer. Environment Canada highlights five measures being taken tocontrol Canada's ozone depleting substances:"Canada's ozone depleting substance phase-out plan, developed as a result of theMontreal Protocol, has accomplished many of its goals already."Most new cars with air conditioning manufactured in Canada are now fitted withhydrofluorocarbon air conditioning systems that use HFC-134a (hydrofluorocarbon134-a).

HCFCs and HFCs have been introduced to replace CFCs. On average, HCFCshave about 5% of the ozone-depleting potential of CFCs."Recovery and recycling regulations for ozone depleting substances (notincluding methyl bromide) are in place in 9 out of the 10 provinces, whileNewfoundland and Yukon are in the process of drafting regulations. Guidelinesare being prepared in the Northwest Territories."On August 10, 1995, the Zer-O-Zone project was launched at Winnipeg City Hall. The project, which is an initiative of the Sierra Club, is intended to fosterpublic awareness of and support for Manitoba's Ozone Protection Regulation."Canada has established bilateral agreements for ozone depleting substancetechnology and information transfer with China, Brazil and Venezuela."A Multilateral Fund has been set up by industrialized countries under theMontreal Protocol to assist developing countries in the phase-out of controlledsubstances. (Environment Canada, 1996) Acid rain, the widely used term for precipitation acidified by atmosphericpollutants may be either dry or wet deposition. Acid rain is caused bypollutants such as sulphur dioxide (SO2 ) and nitrogen oxides (NOx), thesepollutants originate from fossil fuel burning utilities, industrial andautomotive sources.

In the atmosphere sulphur dioxide (SO2) and nitrogen oxides (NOx) are converted chemically to sulphuric acid and nitric acid respectively. Diluted forms of these acids fall to the earth surface as rain, hail, drizzle,freezing rain, snow or fog (wet deposition), they are also deposited as acid gasor dust (dry deposition). Normal rain (pH 5.6) is slightly acidic, but acidrain can be as much as 100 times more acidic (Watt, 1987). With the burning offossil fuels these chemicals are released into the atmosphere, acidic pollutantsmay be transported great distances by the prevailing winds, winds aloft andweather systems before being deposited. It is estimated that more than 50% ofthe acid rain that falls in eastern Canada comes from US. sources (U.S. Environmental Protection Agency, 1991).

Natural sources of SO2 and NOx do exist. In comparison though more than 90% of the SO2 and NOx emissions occurring inNorth America are from human activity. In Canada, the largest sources of SO2 arethe smelting or refining of sulphur-bearing metal ores and the burning of fossilfuels for energy. NOx pollutants are formed during the combustion of fossilfuels in transportation (responsible for 35% of total emissions), industrialprocesses / fuel combustion (23%), power generation (12%) and other sources (30%) (River Road Environmental Technology Centre, 1991). Of Canada's total land area,about 4 million km2 or 43% is highly sensitive to acid rain (Hughs, 1991). Withlittle ability to neutralize acidic pollutants eastern Canada is more seriouslyaffected by acid deposition.

Eastern Canada being composed of thin, coarselytextured soil (glacial till) and granite bedrock (characteristic of the CanadianShield) do not have the buffering ability found in the deeper organic soils ofwestern Canada. Further, eastern Canada receives more acidic deposition than anyother region in Canada. Acid rain is a less serious problem in western Canadabecause of lower overall exposure to acidic pollutants and a generally lessacid-sensitive environment. However, the northern parts of Manitoba andSaskatchewan, along with the north eastern corner of Alberta remain in theCanadian Shield region, and are more affected by acid deposition. Acid rain maycontribute to declining growth rates and increased death rates in trees. Forexample, instances of dieback and deterioration have been noted in white birchin southeastern New Brunswick caused by acid fog, and acidic cloud precipitation (Hughs, 1991).

High levels of acidic deposition result in the acidification ofacid-sensitive lakes, rivers and streams and cause metals to leach fromsurrounding soils into the water system. High acidity and elevated levels ofmetals (notably aluminum) can seriously impair the ability of water bodies tosupport aquatic life, resulting in a decline in species diversity. Lakes andstreams in areas that receive high levels of acidic deposition are currentlybeing monitored to check their acidification status. Over the past decade, 33%of the monitored Canadian lakes showed evidence of improvement, 11% continued toacidify and the rest remained unchanged in acidity (Environment Canada, 1996). Aquatic sensitivity, with respect to aquatic sensitivity classes (high, moderate,low) New Brunswick, Nova Scotia, Prince Edward Island, and Newfoundland areamong the top six provinces with eighty plus percent of their lakes in themoderate to high sensitivity classes. Table 1.0 AQUATIC SENSITIVITY, BY PROVINCEFreshwater Areas in Aquatic SensitivityHigh Mod.

Low %High / mod. British Columbia 32 44 18 73% Alberta 6 21 70 28% Saskatchewan 37 3 56 42% Manitoba 30 2 38 46% Ontario 34 20 20 73% Quebec 328 7 94% New Brunswick 31 4912 87% Nova Scotia 54 33 1982% Prince Edward Island 26 56 <1 99%Newfoundland 56 30 4 96% (Union ofConcerned Scientists, 1996) In Newfoundland the lack of water treatment in some rural communities hasresulted in an increase of potable water acidity. With the use of copper pipingfor water main use in Newfoundland, acidic water can cause serious problems. The acidity causes the leeching of the copper away from the water main pipe andinto the water system causing increased copper content in the water as well asproblems dealing with water main leaks and breakage's. The same problem isevident with the use of asbestos cement pipe. However the leeching of cementaway from the pipe allows the release of the asbestos fibers into the watersystem.

Asbestos is carcinogenic, and therefore this problem arises serioushealth concerns. Human exposure to particulate matter, including sulphate andacidic aerosols, which penetrate deep into the lungs and leads to increasedrespiratory problems. Recent research indicates a relationship between decreasedlung function, increased cardio-respiratory mortality and long-term exposure toambient acidic aerosols. SO2 and its by-products have been linked with rates ofdeterioration in building materials, such as cement, limestone and sandstone.

Some of the Atlantic Province's significant historic structures (for example,the Basilica, St. John's) are slowly being eroded by acidic pollutants. ACanadian Acid Rain Control Program was formalized in 1985 by establishingfederal-provincial agreements with the seven provinces east of Saskatchewan. Participating provinces agreed to reduce their combined SO2 emissions to 2.3million tonnes per year by 1994. This target was exceeded in 1993. Total easternCanadian SO2 emissions were 1.7 million tonnes in 1994, representing a 56%reduction from 1980 levels.

In 1991, Canada signed an agreement with the UnitedStates for the reduction of SO2 and NOx emissions. Canada's obligations underthis agreement include the establishment of a permanent national limit on SO2 of3.2 million tonnes by the year 2000 and a 10% reduction in projected NOxemissions from stationary sources by the same year (NB., NF., NS., Departmentsof Environment, 1991). In 1995, Canada began to develop a national strategydealing with acidic deposition and acidifying emissions. Furthermore, theformulation of new deposition objectives for beyond year 2000.

The aim is toprotect acid-sensitive ecosystems, human health and air visibility in Canada andensure the achievement of its international commitments. This strategy will beconsidered by federal and provincial / territorial Ministers of Energy andEnvironment in 1997 (Ryan, 1996). The Five major environmental pollution sources in Newfoundland and Labrador are: " Municipal Sewage " Vehicle Emissions " Municipal Solid Waste "Total Carbon Dioxide (CO2) output " Primary Natural Resource Processing" Municipal sewage is a problem affecting all the Atlantic provinces. 150,000m3 of untreated sewage is discharged daily in to Halifax harbour (Whelan, 1996). With a common lack of waste treatment in the Atlantic provinces, except PEI. ,actions throughout the Atlantic Provinces should be taken. The St. John'sharbour is a similar situation to the Halifax harbour.

Although St. John's hasa smaller population the narrows at the harbour entrance poses problems as well. The tidal current is impeded by the narrows not allowing the waste products tobe totally removed from the harbour. The rural areas of Newfoundland althoughmuch smaller still remain with no waste treatment facilities. Sediments arecontaminated with organic matter, heavy metals, and organic chemicals such asPAHs and PCBs (Whelan, 1996). Primary treatment plants should be facilitated inmajor population centers around Newfoundland and possible secondary treatmentshould be explored as well.

Many small rural communities could maintain therepresent waste disposal into the Atlantic pending proper environmental study todetermine if the area can handle the small volume of decomposing waste. However,with population increase sewage treatment plants should be facilitated in thesearea's, as they should have been many years ago in St. John's, and other majorcenters in Newfoundland". Vehicle Emissions are not only a Newfoundlandproblem but a major global problem. The demand for personal transportation isnot likely to change in Newfoundland in the future, and national trends show anincrease in the number of vehicles on the roads in Canada (Environment Canada,1996). The main action that must be taken to minimize vehicle emissions are theadoption of vehicle emissions control program in Newfoundland. This would causeall vehicles on the road to maintain a minimum standard of fuel emissionproduction.

High occupancy vehicle lanes and other similar incentives could beimplemented. Testing is going on presently in some Canadian cities to encourageride-sharing and improving fuel efficiency per passenger-kilometer (Maddocks,1996). Ultimately research into alternative fuels, electric vehicles, hydrogenfuel cells, and radically redesigned light-weight super fuel efficientautomobiles suggest that there is significant potential for improving energyefficiency and reducing vehicle emissions. Although this last point is a broadscope for the Newfoundland vehicle emission problem, this problem is global andtherefore global cooperation in research is vital to minimizing this problem. "Municipal Solid Waste has been on the increase over past decades.

In NewBrunswick if trends continue the average waste generated per person will beapproximately 550 kg by 1997, up from approximately 350 kg in 1967 (Maddocks,1996). Solid waste is disposed of in small dump sites, large landfills and byincineration. In Newfoundland there is a relatively large number of screenedincinerators. However with the global push to lower atmospheric air pollutants,incineration, although space conducive, also maintains its problems.

All threeforms of waste management have there problems. With the formation of betterlandfill design and site choice, landfills are becoming better managed andbetter contained. In the long term the only way to curb the production in solidwastes is to bring about a reduction of wastes produced. The use of compostingis useful in the deposing of organic waste, however with regional composting youagain run into the problem of site selection, due to public opposition.

Theproblem of both land and sea persistent litter is also a problem in Newfoundland. A hazard to both aesthetics and marine animals (through entanglement andingestion). A reduction is garbage produced per person is ultimately the bestway to solve the problem. The national Packaging Protocol calls for a reductionin packaging of 50%, over the 1988 levels, by the year 2000 (Maddocks, 1996). These are the kinds of reduction in produced waste that are beneficial to solidwaste management". Total Carbon Dioxide (CO2) output is a combination of homeburning of oil and wood for heating, the refining of the fossil fuels for theuse in the heating and powering of gasoline engines, and the production ofelectrical power (Maddocks, 1996).

Although Newfoundland power pushes people touse electricity for the use in heat, many people are still using oil in theirhomes. Surprisingly enough the oil fuelled furnace is more fuel efficient thenthe oil burning electrical power station supplying St. John's with itselectricity (Dawne, 1996). In rural areas of Newfoundland many people areheating their homes with wood, this has a very high percentage of carbon dioxidefor the relative heat in BTU's. With the extreme need for a good fuel efficientsource of heat during the long Newfoundland winter, it is evident other fuelsources must be explored. With fossil fuels being the cheapest form of heat,economics will play major role in the choices available. There is still room,however, for better fuel efficiency and reduced carbon dioxide emissions.

Theuse of less polluting fuels, such as natural gas should be examined. Theeconomic benefit of finding a cleaner, and cheaper source of heat is extremelyimportant. The full range of environmental and economic impacts over its lifecycle (extraction, refinement, and use) needs to be considered, whatever fuel isused". Primary Natural Resource Processing can be split into two groups withPulp and Paper Mills and Fish and Food Processing Plants, the NewfoundlandDepartment of the Environment does not include Mining and Smelting in this groupof polluters (Whelan, 1996). Pulp and Paper Mills are responsible for thedischarge of effluents containing organic wastes and suspended solids to freshand coastal waters.

Effluents from the plants in Newfoundland produce a varietyof toxic organo-chlorine compounds, including dioxins and furans. The formationof organic acids, due to the decomposition of wood, particulate matter alsoposes a problem. The volume of wood waste that is dumped into rivers and baysin Newfounland have caused the formation of toxic carcinogenic fish habitatenviroments (Whelan, 1996). With new regulatory measures in place theenvironmental stress on the water ways will be reduced, however, even thoughsulphur dioxide air emissions have been reduced, noxious odours continue to bean aesthetic problem. The technology has come available in recent years for theuse of a closed water system for pulp and paper plants. This system, however isnot widely used because of the setup cost.

Closed water systems would almostentirely eliminate the noxious odour problem and largely decrease the need todump effluents into fresh and coastal waters. The technology is available, onceagain the problem of the economics behind the production is the main concern. Fish Processing Plants operating in Newfoundland, however drastically reducedsince 1992, primarily stress the environment by releasing high-strength oxygen-demanding wastes to the coastal environment. Harmful bacteria in planteffluents, and nuisance odours are also a potential concern.

With themoratorium on the cod fishery in 1992, the closure of many fish plants wasactually a multifaceted benefit to the environment, both to the areassurrounding the plants and to the cod fishery.

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