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A combination of fog and chemicals that come from automobile and factory emissions and is acted upon by the action of the sun


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  • 2. ACKNOWLEDGEMENT We take this opportunity to express my profound sinceregratitude to all those who helped me to carry out this projectsuccessfully. We owe our sincere gratitude to our Principal Dr. M.Z.Shaikhand also to our college committee members for giving theencouragement that helped us to complete the project successfully. Our sincere thanks to Mrs S.D.Jadhav, Head of the Department ofMechanical engineering, Bharati Vidyapeeth college of engineering,who inspired us with his valuable suggestions and advice throughoutour lectures. We also express our sincere thanks to all other staffmembers. We express our sincere gratitude to our External guide Mrs.Reshma Ahmed (Mam) Technologies for sparing his valuable time ingiving the valuable information and suggestions all through, for thesuccessful completion of the project. At the very outset we convey our gratitude to our Internal GuideMrs. Reshma Ahmed (Mam), Lecturer for Mechanical Department,for allowing us to do project and enabling us to complete the samesuccessfully. We express our profound gratitude for his valuableguidance and support.We extend our thanks to our Class Teacher, Mr.Pramod Kothmirefor his valuable suggestions during the project work.We here by thank one and all who extended their helping hand in theaccomplishment of the project.
  • 3. Titles 1 Definition 1 2 Description 2 3 Development/Formation 3 4 Chemical Reaction Occurence 5 5 Health Effects 6 6 Natural Causes 6 7 Areas Affected 7 8 Pollution Index 11 9 Prevention/Solutions 11 10 Bibliography 12
  • 4. DEFINITION OF PHOTOCHEMICAL SMOG A combination of fog and chemicals that come fromautomobile and factory emissions and is acted upon bythe action of the sun. Nitrogen dioxide, in the presenceof the sun and some hydrocarbons, is turned into nitric oxide and atomic oxygen. The atomic oxygen reacts with the oxygen molecules and other constituents ofautomobile exhaust fumes to form a variety of products including ozone. The ozone is harmful in itself and isalso implicated in a highly complex series of continuing reactions. Is completely being photochemical smog
  • 5. DESCRIPTION:-Definition o Carbon monoxide and sulfur oxide are considered primary pollutants. These pollutants undergo chemical changes and cause secondary effects such as smog. Air pollution is defined by the existence and integration of toxic compounds in the atmosphere in concentrations high enough to cause harm to humans, animals and the Earths environment.Cause o Burning fossil fuels emits carbon monoxide and sulfur oxide. Automobiles, buses, planes and any form of gas-fueled transportation emit carbon monoxide gases through exhaust systems. Sulfur dioxide is created through the burning of coal, and is associated with industrial waste. Manufacturing processes use coal for fuel, releasing sulfur dioxide into the air through the factory exhaust systems.Effects o Air pollution is the source of smog, acid rain and possibly global warming. Smog is classified as either photochemical smog or industrial smog. Photochemical smog, often evidenced by the brown cloud hanging over densely populated cities, is created by the interaction of sunlight with molecules of primary pollutants. The resulting chemical reaction is toxic to humans and animals. Industrial smog is characterized by the gray-brown fog that hangs over industrial areas and is attributed to the interaction of sunlight, air molecules and sulfur dioxide. The result is, again, toxic air.Considerations o Individuals and businesses alike have taken steps to reduce their contributions to air pollution. Manufacturing and purchasing vehicles that use gas more efficiently and driving less, recycling to reduce landfills that emit toxic gases and patronizing those businesses that reduce their industrial waste all aid in controlling air pollution. These actions, while laudable, act as a preventative only in reducing the amount of toxins spewed into the Earths atmosphere.
  • 6. SMOGSmog is a type of air pollution; the word "smog" was coined in the early 20thcentury as a portmanteau of the words smoke and fog to refer to smoky fog. Theword was then intended to refer to what was sometimes known as pea soup fog,a familiar and serious problem in London from the 19th century to the mid20th century. This kind of smog is caused by the burning of large amounts ofcoal within a city; this smog contains soot particulates from smoke, sulfur dioxideand other components. Modern smog, as found for example in Los Angeles, is atype of air pollution derived from vehicular emission from internal combustionengines and industrial fumes that react in the atmosphere with sunlight to formsecondary pollutants that Photochemical smog.Photochemical smog was first described in the 1950s. It is the chemical reaction of sunlight,nitrogen oxides and volatile organic compounds in the atmosphere, which leaves airborneparticles and ground-level ozone. This noxious mixture of air pollutants can include thefollowing: Nitrogen oxides, such as nitrogen dioxide PeroAldehydes xyacyl nitrates Tropospheric ozone Volatile organic compoundsAll of these chemicals are usually highly reactive and oxidizing. Photochemical smog istherefore considered to be a problem of modern industrialization. It is present in all moderncities, but it is more common in cities with sunny, warm, dry climates and a large number ofmotor vehicles. Because it travels with the wind, it can affect sparsely populated areas as well.
  • 7. Development of Photochemical SmogCertain conditions are required for the formation of photochemical smog. These conditionsinclude:1. A source of nitrogen oxides and volatile organic compounds. High concentrations of thesetwo substances are associated with industrialization and transportation. Industrialization andtransportation create these pollutants through fossil fuel combustion.2. The time of day is a very important factor in the amount of photochemical smog present. Thefollowing illustrates the daily variation in the key chemical players. The diagram suggests: Early morning traffic increases the emissions of both nitrogen oxides and VOCs as people drive to work. Later in the morning, traffic dies down and the nitrogen oxides and volatile organic compounds begin to be react forming nitrogen dioxide, increasing its concentration. As the sunlight becomes more intense later in the day, nitrogen dioxide is broken down and its by-products form increasing concentrations of ozone. At the same time, some of the nitrogen dioxide can react with the volatile organic compounds to produce toxic chemicals such as PAN. As the sun goes down, the production of ozone is halted. The ozone that remains in the atmosphere is then consumed by several different reactions.3. Several meteorological factors can influence the formation of photochemical smog. Theseconditions include: Precipitation can alleviate photochemical smog as the pollutants are washed out of the atmosphere with the rainfall. Winds can blow photochemical smog away replacing it with fresh air. However, problems may arise in distant areas that receive the pollution. Temperature inversions can enhance the severity of a photochemical smog episode. Normally, during the day the air near the surface is heated and as it warms it rises, carrying the pollutants with it to higher elevations. However, if a temperature inversion develops pollutants can be trapped near the Earths surface. Temperature inversions cause the reduction of atmospheric mixing and therefore reduce the vertical dispersion of pollutants. Inversions can last from a few days to several weeks.4. Topography is another important factor influencing how severe a smog event can become.Communities situated in valleys are more susceptible to photochemical smog because hills andmountains surrounding them tend to reduce the air flow, allowing for pollutant concentrationsto rise. In addition, valleys are sensitive to photochemical smog because relatively strongtemperature inversions can frequently develop in these areas
  • 9. Chemistry of Photochemical SmogThe previous section suggested that the development of photochemical smog is primarilydetermined by an abundance of nitrogen oxides and volatile organic compounds in theatmosphere and the presence of particular environmental conditions. To begin the chemicalprocess of photochemical smog development the following conditions must occur: Sunlight. The production of oxides of nitrogen (NOx). The production of volatile organic compounds (VOCs). Temperatures greater than 18 degrees Celsius.If the above criteria are met, several reactions will occur producing the toxic chemicalconstituents of photochemical smog. The following discussion outlines the processes requiredfor the formation of two most dominant toxic components: ozone (O3) and peroxyacetylnitrate (PAN). Note the symbol R represents a hydrocarbon (a molecule composed of carbon,hydrogen and other atoms) which is primarily created from volatile organic compounds.Nitrogen dioxide can be formed by one of the following reactions. Notice that the nitrogenoxide (NO) acts to remove ozone (O3) from the atmosphere and this mechanism occursnaturally in an unpolluted atmosphere. O3 + NO »»» NO2 + O2 NO + RO2 »»» NO2 + other productsSunlight can break down nitrogen dioxide (NO2) back into nitrogen oxide (NO). NO2 + sunlight »»» NO + OThe atomic oxygen (O) formed in the above reaction then reacts with one of the abundantoxygen molecules (which makes up 20.94 % of the atmosphere) producing ozone (O3). O + O2 »»» O3Nitrogen dioxide (NO2) can also react with radicals produced from volatile organiccompounds in a series of reactions to form toxic products such as peroxyacetyl nitrates (PAN). NO2 + R »»» products such as PANIt should be noted that ozone can be produced naturally in an unpolluted atmosphere. However,it is consumed by nitrogen oxide as illustrated in the first reaction. The introduction of volatileorganic compounds results in an alternative pathway for the nitrogen oxide, still formingnitrogen dioxide but not consuming the ozone, and therefore ozone concentrations can beelevated to toxic levels.
  • 10. Health effectsHighland Park Optimist Club wearing smog-gas masks at banquet, Los Angeles, circa 1954The Ontario Medical Association announced that smog is responsible for an estimated 9,500premature deaths in the province each year.A 20-year American Cancer Society study found that cumulative exposure also increases thelikelihood of premature death from a respiratory disease, implying the 8-hour standard may beinsufficient. Natural causesAn erupting volcano can also emit high levels of sulphur dioxide along with a large quantity ofparticulate matter; two key components to the creation of smog. However, the smog created as aresult of a volcanic eruption is often known as "vog"[citation needed] to distinguish it as a naturaloccurrence.The radiocarbon content of some plant life has been linked to the distribution of smog in someareas. For example; presence of Creosote bush in the Los Angeles area has been shown to havean effect on smog distribution that is more than fossil fuel combustion alone. Areas affectedBeijing air on a day after rain (left) and a smoggy day (right)Smog can form in almost any climate where industries or cities release large amounts of airpollution, such as smoke or gases. However, it is worse during periods of warmer, sunnierweather when the upper air is warm enough to inhibit vertical circulation. It is especiallyprevalent in geologic basins encircled by hills or mountains. It often stays for an extendedperiod of time over densely populated cities or urban areas, and can build up to dangerouslevels.
  • 11. 1).London, United KingdomVictorian London was notorious for its thick smogs, or "pea-soupers", a fact that is oftenrecreated (as here) to add an air of mystery to a period costume drama2).Mexico City, MexicoDue to its location in a highland "bowl", cold air sinks down onto the urban area of MexicoCity, trapping industrial and vehicle pollution underneath, and turning it into the mostinfamously smog-plagued city of Latin America. Within one generation, the city has changedfrom being known for some of the cleanest air of the world into one with some of the worstpollution, with pollutants like nitrogen dioxide being double or even triple internationalstandards. Photochemical Smog Over Mexico City December 2010.3).Santiago, ChileSimilar to Mexico City, the air pollution of Santiago valley located between the Andes andChilean Coast Range turning it into the most infamously smog-plagued city of South America.Other aggravant of the situation resides in its high latitude (31 degrees South) and dry weatherat most part of the year.
  • 12. 4).Tehran, IranIn December 2005, schools and public offices had to close in Tehran, Iran and 1600 peoplewere taken to hospital, in a severe smog blamed largely on unfiltered car exhaust.5).United States A NASA astronaut photograph of a smog layer over central NewYork.Counties in the United States where one or more National Ambient Air Quality Standards arenot met, as of June 2007.Smog was brought to the attention of the general US public in 1933 with the publication of thebook "Stop That Smoke", by Henry Obermeyer, a New York public utility official, in which hepointed out the effect on human life and even the destruction of 3,000 acres (12 km2) of afarmers spinach crop. Since then, the United States Environmental Protection Agency hasdesignated over 300 U.S. counties to be non-attainment areas for one or more pollutants trackedas part of the National Ambient Air Quality Standards. These areas are largely clustered aroundlarge metropolitan areas, with the largest contiguous non-attainment zones in California and theNortheast. Various U.S. and Canadian government agencies collaborate to produce real-time airquality maps and forecasts.
  • 13. Los Angeles and the San Joaquin ValleyBeing in low basins surrounded by mountains, Los Angeles and the San Joaquin Valley arenotorious for their smog. The millions of vehicles in these basins plus the added effects of theSan Francisco Bay and Los Angeles/Long Beach port complexes contribute to further airpollution. While strict regulations by the multiple California government agencies overseeingthis problem have reduced the number of Stage 1 smog alerts from several hundred annually tojust a few, these geologically predisposed entrapment zones collect pollution levels from cars,trucks and fixed sources which still exceeds health standards and is a pressing issue for themore than 25 million people who live there.Major incidents in the US 1948, October 30–31, Donora, PA: 20 died, 600 hospitalized, thousands more stricken. Lawsuits were not settled until 1951. 1953, November, New York: Smog kills between 170 and 260 people. 1954, October, Los Angeles: heavy smog shuts down schools and industry for most of the month. 1963, New York: blamed for 200 deaths6).Ulaanbaatar, MongoliaIn late 1990s to early 2000 a massive immigration to Ulaanbaatar from countryside begun,causing air pollution in Ulaanbaatar. Estimated 150,000 households mainly living in traditionalMongolian gers in outskirts of Ulaanbaatar burn wood and coal (some poor families burn evencar tires & trash) to heat themselves during harsh winter that lasts from October to April sincethese outskirts are not connected to the citys central heating system. A temporary solution todecrease smog is proposed in forms of stoves with improved efficiency although with no visibleresults.7).Southeast AsiaSingapores Downtown Core on 7 October 2006, when it was affected by forest fires inSumatra, IndonesiaSmog is a regular problem in Southeast Asia caused by land and forest firesin Indonesia, especially Sumatra and Kalimantan, although the term haze is preferred indescribing the problem
  • 14. Pollution index The severity of smog is often measured using automated optical instruments such as Nephelometers, as haze is associated with visibility and traffic control in ports. Haze however can also be an indication of poor air quality though this is often better reflected using accurate purpose built air indexes such as the American Air Quality Index, the Malaysian API (Air Pollution Index) and the Singaporean Pollutant Standards Index. In hazy conditions, it is likely that the index will report thesuspended particulate level. The disclosure of the responsible pollutant is mandated in somejurisdictions. Prevention / Solution o Air pollution may be prevented only if individuals and businesses stop using toxic substances that cause air pollution in the first place. This would require the cessation of all fossil fuel-burning processes, from industrial manufacturing to home use of air conditioners. This is an unlikely scenario at this time. However, as of June 2010, the Environmental Protection Agency (EPA) put forth a proposal for a Federal Transport Rule, which sets stringent regulations on industrial and power supply manufacturing and handling. The regulations are designed to further reduce harmful emissions into the Earths atmosphere. o Reducing vehicle exhaust emissions NO and another important source of hydrocarbons is vehicle exhaust emissions. When the fuel during combustion in the engine cylinder, owing to internal combustion engines with fuel containing impurities other than carbon, hydrogen, oxygen, incomplete combustion of internal combustion engines, tail gas containing a certain amount of emissions of CO, hydrocarbons, NO, particulate matter and ozone (formaldehyde, Acrolein, and so on. o If oxide. Such a catalyst can be a combination of platinum or rhodium or just platinum. Since platinum catalyses un-burnt hydrocarbon and oxygen reaction, resulting in production of carbon-dioxide and water vapor, the formation of ozone is nullified. Similarly, rhodium can also help by oxidizing all the carbon monoxide to carbon dioxide. If automobiles use unleaded petrol, the catalytic converters can automobiles are provided with catalytic converters, it can reduce the emissions of carbon monoxide and nitrogen be used.
  • 15. BIBLIOGRAPHYo o l pollutant.htm lication.html