Air Pollution Essay

IntroductionThe earths atmosphere, at or near sea train, consists approximately of 78 percent nitrogen, 21 percent oxygen and 1 percent early(a) gases. If it were possible to roost in this state, 100 percent clean activate would result. However, many wide-ranging starts allow other gases and particulates to mix with the clean seam, causing our atmosphere to fabricate unclean or polluted. Some of these pollutants atomic number 18 visible while others are invisible, with each having the capability of causing distress to the eyes, ears, throat, skin and respiratory system. Should these pollutants develop concentrated in a specific area and under sealed conditions, death could result due to the dis bewilderment or chemical replace of the oxygen content in the circularize. These pollutants can also cause big damage to the environment and to the many man made objects that are exposed to the elements. To better understand the causes of business line pollution, the pollutants can be categorized into 3 separate typesetters cases, instinctive, industrial and automotive.Natural PollutantsNatural pollution has been present on earth since before man appeared and continues to be a factor when discussing subscriber line pollution, although it causes only a small percentage of the everyplaceall pollution problem. It is the form result of decaying organic matter, wind born booby and particulates from such natural events as plain and forest fires (ignited by awake or lightning), volcanic ash, sand and dust which can spread everyplace a man-sized area of the countryside.Such a phenomenon of natural pollution has been seen in the d blunt of volcanic eruptions, with the resulting plume of good deal, steam and volcanic ash blotting come out of the closet the lies rays as it spreads and rises higher into the atmosphere. As it travels into the atmosphere the upper air currents catch and carry the smoke and ash, while condensing the steam O.K. into water vapor. As the water vapor, smoke and ash travel on their journey, the smoke dissipates into the atmosphere while the ash and moisture settle dressing to earth in a trail hundreds of miles long. In some cases, lives are lost and millions of dollars of property damage result.Industrial PollutantsIndustrial pollution is caused in the beginning by industrial processes, the burning of coal, oil and natural gas, which in sport produce smoke and fumes. Because the burning burn downs contain large come ins of sulfur, the principal ingredients of smoke and fumes are sulfur dioxide and particulate matter. This type of pollutant occurs most heavily during still, damp and cool weather, such as at night. Even in its less severe form, this pollutant is non confined to just cities.Because of air go forwardments, the pollutants break for miles over the surrounding countryside, leaving in its path a guiltless and unhealthy environment for all living things. Working with Federal, State and local anaesthetic mandated regulations and by carefully monitoring releases, big business has greatly reduce the amount of pollutant introduced from its industrial sources, striving to obtain an acceptable level. Because of the mandated industrial emission clean up, many land areas and streams in and around the cities that were formerly detached of vegetation and life, have now begun to move back in the nidus of natures intended balance.Automotive PollutantsThe third major source of air pollution is automotive emissions. The emissions from the subjective burning engines were not an appreciable problem years ago because of the small number of registered vehicles and the nations small highway system. However, during the early 1950s, the trend of the American people was to move from the cities to the surrounding suburbs. This caused an immediate problem in transportation because the majority of suburbs were not afforded gage transit conveniences. This lack of transportation cr eated an attractive market for the motorcar manufacturers, which resulted in a dramatic increase in the number of vehicles produced and sold, along with a marked increase in highway construction betwixt cities and the suburbs.Multi-vehicle families emerged with a growing emphasis placed on an individual vehicle per family member. As the increase in vehicle ownership and usage occurred, so did pollutant levels in and around the cities, as suburbanites drove daily to their businesses and employment, returning at the end of the day to their homes in the suburbs. It was noted that a smoke and murkiness type haze was being formed and at times, remained in jailbreak over the cities, taking time to dissipate. At first this smogginess, derived from the words smoke and fog, was thought to result from industrial pollution but it was determined that railway car emissions shared the blame.It was discovered that when everyday railcar emissions were exposed to sunlight for a period of time, complex chemical reactions would take place. It is now known that smog is a photo chemical bottom which develops when certain oxides of nitrogen (NOx) and unburned hydrocarbons (HC) from automobile emissions are exposed to sunlight. Pollution was more severe when smog would get under ones skin stagnant over an area in which a warm layer of air settled over the top of the cool air big bucks, lodging and holding the cooler mass at base level. The trapped cooler air would keep the emissions from being dispersed and diluted done normal air flows. This type of air stagnation was given the name Temperature Inversion.TEMPERATURE upendingIn normal weather situations, move up air is warmed by heat radiating from the earths surface and the suns rays. This causes it to rise upward, into the atmosphere. Upon rising it will cool through a convection type heat exchange with the cooler upper air. As warm air rises, the surface pollutants are carried upward and dissipated into the atmosph ere. When a temperature sexual inversion occurs, we distinguish the higher air is no longer cooler, but is warmer than the surface air, causing the cooler surface air to become trapped. This warm air blanket can extend from above ground level to a few hundred or even a few kibibyte feet into the air. As the surface air is trapped, so are the pollutants, causing a severe smog condition. Should this stagnant air mass extend to a few thousand feet high, enough air movement with the inversion takes place to allow the smog layer to rise above ground level but the pollutants still cannot dissipate.This inversion can remain for days over an area, with the smog level only rising or lowering from ground level to a few hundred feet high. Meanwhile, the pollutant levels increase, causing eye irritation, respiratory problems, reduced visibility, plant damage and in some cases, even disease. This inversion phenomenon was first noted in the Los Angeles, California area. The city lies in terrai n resembling a basin and with certain weather conditions, a cold air mass is held in the basin while a warmer air mass covers it like a lid. Because this type of condition was first documented as prevalent in the Los Angeles area, this type of trapped pollution was named Los Angeles Smog, although it occurs in other areas where a large concentration of automobiles are used and the air trunk stagnant for any length of time.HEAT TRANSFERConsider the internal combustion engine as a machine in which raw materials must be placed so a finished ware comes out. As in any machine operation, a certain amount of wasted material is formed. When we relate this to the internal combustion engine, we find that through the input of air and raise, we obtain power during the combustion process to draw a bead on the vehicle. The by-product or waste of this power is, in part, heat and get gases with which we must dispose. The heat from the combustion process can rise to over 4000F (2204C). The diss ipation of this heat is figureled by a ram air effect, the use of cooling fans to cause air flow and a fluid coolant solution surrounding the combustion area to transfer the heat of combustion through the cylinder walls and into the coolant.The coolant is then directed to a thin-finned, multi-tubed radiator, from which the excess heat is transferred to the atmosphere by 1 of the 3 heat transfer methods, conduction, convection or radiation. The cooling of the combustion area is an important part in the control of polish off emissions. To understand the behavior of the combustion and transfer of its heat, consider the air/fuel charge. It is ignited and the flame front burns progressively across the combustion chamber until the burning charge reaches the cylinder walls. Some of the fuel in match with the walls is not hot enough to burn, thereby snuffing out or quenching the combustion process.This leaves unburned fuel in the combustion chamber. This unburned fuel is then forced ou t of the cylinder and into the exhaust system, along with the exhaust gases. Many attempts have been made to minimize the amount of unburned fuel in the combustion chamber due to quenching, by increasing the coolant temperature and lessening the contact area of the coolant around the combustion area. However, design limitations within the combustion chambers prevent the complete burning of the air/fuel charge, so a certain amount of the unburned fuel is still expelled into the exhaust system, regardless of modifications to the engine.