Smog

Smog

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  SMOG • Smog isa form of air pollution caused by tiny particles in the air. • The term smog was first coined in 1905 in a paper by Dr. Henry Antoine Des Voeux to describe combination of smoke and fog. • It is hazy mixture of heavily polluted air that can form in cities due to the emissions of sulfur dioxide and aerosols from the burning of fossil fuels (primarily coal and oil). • It is generally formed in winter under calm, stable, and moist conditions. • The term is now applied to all forms of severe air pollution, particularly in urban areas, that restrict visibility and people suffer from breathing problems.
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  TYPES OF SMOG CLASSICAL/ INDUSTRIAL SMOG PHOTOCHEMICAL SMOG
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  INDUSTRIAL SMOG • Classicsmog forms in areas with high water vapor and high levels of sulfur emissions, usually from burning coal. • Sulfur particles dissolve into water droplets to form sulfuric acid in the atmosphere, while coal soot darkens the skies. • This type of smog is most commonly associated with London and is also referred as “London Smog” or Sulphurous smog and causes dark brownish colour of atmosphere. • The main constituent of London-type smog is soot and it also contain large quantities of fly ash, sulfur dioxide, sodium chloride, and calcium sulfate particles.
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  INDUSTRIAL SMOG REACTIONS • Ifconcentrations are high, sulfur dioxide can react with atmospheric hydroxide to produce sulfuric acid, that will precipitate as acid rain. SO2+OH . → HOSO2 HOSO2+O2 → HO2+SO3 SO3+H2O → H2SO4 C + O2 → CO2 2C + O2 → 2CO S + O2 → SO2 2SO2 + O2 → 2SO3 SO3 + H2O → H2SO4 2NH3 + H2SO4 → (NH4)2SO4
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  PHOTOCHEMICAL SMOG • Itis the haze created when sunlight reacts with primary pollutants like nitrogen oxides and volatile organic compounds that can be found in fossil fuel emissions from automobiles, factories, and power plants. • These reactions create secondary pollutants and are characterized by high concentrations of a large variety of pollutants, such as nitrogen oxides, O3, CO, hydrocarbons, aldehydes (and other materials that are eye irritants), and sometimes sulfuric acid as well. • Photochemical smog is a problem in large cities around the world and is best exemplified by cities like Los Angeles, Mexico city etc.
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  PHOTOCHEMICAL SMOG REACTIONS
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  SMOG TYPES -SUMMARY
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  EFFECT OF SMOG •The major constituents of smog, with the exception of CO2, are powerful poisons. • Smog reduce visibility and create an unattractive haze on the horizon. Photochemical smog causes irritation of the eyes, nose, throat, and chest. Eye irritation is not caused by O3, but by PANs and trace free radical HCs. • Smog can make breathing more difficult by chocking lungs. This can be especially troubling for people with asthma. • Smog pollution has been known to damage crops (blighting plants), as well as to cause health problems in pets and farm animals. • Smog has also been known to cause corrosive damage to buildings and vehicles.
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  SMOG REMEDIES • Conserveenergy - at home, at work, everywhere. • Look for the ENERGY STAR label when buying home or office equipment. • Carpool, use public transportation, bike, or walk whenever possible. • Consider purchasing portable gasoline containers labeled “spill- proof,” where available. • Be sure your tires are properly inflated. • Use environmentally safe paints and cleaning products whenever possible. • Mulch or compost leaves and yard waste. • Avoid burning leaves, trash, and other materials.