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Photochemical Smog

Photochemical Smog. By: Gurjot Singh and Garry Troung. What is Photochemical Smog ?. Photochemical Smog is a type of air pollution that is a combination of pollutants (in the form of smoke) and fog.

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Photochemical Smog

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  1. Photochemical Smog By: Gurjot Singh and Garry Troung

  2. What is Photochemical Smog? • Photochemical Smog is a type of air pollution that is a combination of pollutants (in the form of smoke) and fog. • Created through chemical reactions with pollutants from cars and factories resulted from contact with sunlight • Mostly occurs in highly-populated cities such as Toronto, New York City, London etc. • Occurs during a warm, sunny day

  3. Components of Smog • Nitrogen oxides or NOx • Volatile Organic Compounds( Hydrocarbons or oxygenates) • Ground Level Ozone or O3 • Peroxyacytyl nitrate (PAN)

  4. Nitrogen Dioxide • Reddish Brown Toxic Gas • Comes mainly from automobile exhausts and emissions from power generation plants (fossil fuels burning) • Sharp Odour • Molar Mass : 46.0055 g/mol • When in contact with sunlight, NO2 produces nitric oxide (NO) and Ozone • Is one of the key components in creating PAN Effects: • Irritates the respiratory tract (nose, throat , lungs etc.) • Can cause severe to life threatening lung damage in large enough quantities

  5. Volatile Organic Compounds • Volatile Organic Compounds • Gaseous organic compounds that are created from specific solids and liquids • Released from the burning of fossil fuels, paints, printers, adhesives, permanent markers and aerosols. • Ex. Ethyl acetate, acetone, chlorofluorocarbons • In the atmosphere, it can react with UV rays and NO3 to create ozone • Another component in the creation of PAN • VOCs usually link to chronic illnesses and sometimes cancer • Chlorofluorocarbons (CFCs) were so dangerous to the environment that it was either completely banned or put on extreme restrictions

  6. Ozone • A bluish, toxic gas that consists of 3 oxygen atoms (O3) • Molar Mass 47.998 g/mol • Created when a reactive oxygen atoms combines with oxygen gas (O2) through synthesis • Ground level ozone is also created from exhausts from automobiles • NO2(g)---(sunlight)------->NO(g)+O(g) ; O + O2 -----> O3 • While atmospheric ozone protects us from solar radiation, ground- level ozone in larger amounts are very harmful to both living things and the environment • Can damage lung tissue, cause more frequent asthma and can cause a variety of irritations.

  7. Peroxyacytyl nitrate (PAN) • PAN or C2H3O5N is a toxic gas that is part of smog • Molar Mass : 121.05 g/mol • PAN is formed from the other key components of smog notably nitrogen dioxide, Oxygen and hydrocarbons • NO2(g) + O2(g) + hydrocarbons---sunlight-------> CH3CO-OO-NO2(g) • Is highly reactive and is also a strong oxidizing material Effects: • Can severe irritate the eyes and the respiratory system

  8. Why doesn’t smog occur in the winter or the cooler parts of the seasons? • According to the KMT, particles move in straight line motion and give off the same kinetic energy (frequency of collisions) at a given temperature • In colder temperature, there are less collisions with the particles of NOx , O2, hydrocarbons etc. • These lesser chances of collision reduces the frequency of a reaction occur therefore prevent smog from forming • In warmer temperature, there are more collision resulting in more frequent chemical reactions and the occurrence of photochemical smog

  9. Charles’s Law • At a constant pressure , the volume of a fixed mass of any gas is directly proportional to its Kelvin temperature • The gases that smog is composed of increase in volume or it expands when temperature is increased V1 V2 = _______ _______ T1 T2

  10. Density • Since smog is denser than regular air above sea level, the smog is unable to rise, causing it to be trapped within a low area, eventually resulting in the buildup of pollutants. • Air Density: 1.22521 kg/m3. • Due to the fact that the compounds that were parts of the smog had a greater molar mass and volume than that of regular air • This is also due to an inversion layer occurring in cities that traps the pollutants between a cold air mass and a warm air mass

  11. THE END Any Questions?

  12. Bibliography • http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/AirPollution.html • http://www.windows2universe.org/earth/Atmosphere/smog.html&edu=high • http://en.wikipedia.org/wiki/Nitrogen_dioxide • http://www.epa.gov/iaq/voc.html • http://commons.wikimedia.org/wiki/File:Peroxyacetyl-nitrate-3D-vdW.png • http://www.ausetute.com.au/photsmog.html • http://www.environment.gov.au/soe/2006/publications/drs/indicator/375/index.html • http://www.iqa.mddep.gouv.qc.ca/contenu/noxen.jpg • http://www.mfe.govt.nz/issues/air/images/summersmog.jpg • http://www.mnh.si.edu/archives/garden/images/4seasons.gif

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