Unit 5 ch 12 s1 what causes air pollution

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Unit 5 ch 12 s1 what causes air pollution

  1. 1. Air & Air Pollution Chapter 12, Section 1: What Causes Air Pollution? Standards: SEV3a
  2. 2. What is the normal composition of air?  78% Nitrogen  21% oxygen  1% various other gases like ◦ Argon ◦ Carbon dioxide ◦ Water vapor
  3. 3. What is air pollution?  Any harmful substance that builds up in the air to unhealthy levels.  Can be natural: pollen, dust, gases from volcanoes  Mostly human caused: car exhaust, coal-fired power plants, industrial pollution, etc.
  4. 4. What is the difference between a primary and secondary pollutant?  Primary pollutant ◦ Put directly into air by human activities  Ex: Sulfur dioxide released from burning fossil fuel.  Secondary pollutant ◦ Primary pollutants react with other primary pollutants or water vapor to make a new substance  Ex: Sulfur dioxide mixes with water in atmosphere and causes acid rain.
  5. 5. What are the 5 primary air pollutants? 1. Carbon monoxide 2. Nitrogen oxides 3. Sulfur dioxides 4. Volatile Organic Compounds 5. Particulate Matter
  6. 6. 1. Carbon Monoxide (CO)  Description: ◦ Odorless, colorless ◦ Poisonous ◦ From incomplete combustion of fossil fuels  Primary Source: ◦ Vehicles (cars, trucks, buses) ◦ Industrial processes  Effects: ◦ Blood can’t carry oxygen as well, feel sleepy & disoriented; can cause
  7. 7. 2. Nitrogen Oxides (NOx)  Description: ◦ Can be yellowish gas ◦ Forms under high temps  Primary Source: ◦ Vehicles (cars, trucks, buses) ◦ Power plants ◦ Industrial boilers  Effects: ◦ Brownish haze from smog comes from NOx ◦ Some acid precipitation ◦ Makes body vulnerable to respiratory disease & cancer
  8. 8. 3. Sulfur dioxides (SO2)  Description: ◦ Pungent smell  Primary Source: ◦ Burning fossil fuels  Power plants  Refineries  Smelters ◦ Volcanic activity  Effects: ◦ Contributes to acid rain ◦ Harm plants ◦ Irritate respiratory system
  9. 9. 4. Volatile Organic Compounds (VOCs)  Description: ◦ Organic chemicals ◦ Vaporize readily ◦ Form toxic fumes  Primary Source: ◦ Vehicles (cars, trucks, buses) ◦ Burning fossil fuels  Effects: ◦ Contribute to smog formation ◦ Harm plants ◦ Linked to cancer
  10. 10. 5. Particulate Matter (PM)  Description: ◦ Tiny pieces of liquid or solid matter  Primary Source: ◦ Construction, agriculture, forestry, fires ◦ Vehicles, power plants & Industrial processes  Effects: ◦ Form clouds & reduce visibility ◦ Small pieces can be inhaled & clog respiratory system ◦ Linked to cancer ◦ Corrode metal & erode buildings Divided into: Fine particulate matter (PM 2.5)- from burning fossil fuels; worst because can be inhaled deeper into lungs Coarse particulate matter (PM10)- incinerators, mining, cement plants
  11. 11. How long have air pollution problems been around?  As early as 2000 years ago, people complained of “foul air”  Air pollution problems became worse around the Industrial Revolution of the 1800’s when fossils fuel usage increased and no standards existed for how much pollution Weather History: The Great Smog of 1952- London
  12. 12. What are two main sources of air pollution? 1. Motor Vehicle Emissions 2. Industrial Air Pollution
  13. 13. What are Motor Vehicle Emissions?  Fumes & particulates produced from the burning of gasoline in vehicles  1/3 of air pollution comes from gasoline burned by vehicles.  Clean Air Act- ◦ regulates vehicle emissions ◦ Banned lead in gasoline- lead pollution has decreased by 90% in US. ◦ Catalytic converters clean exhaust gas  EPA says vehicles today burn fuel 35% more efficiently and with 95 % fewer emissions (except CO2) than they did 30 years ago.
  14. 14. What are Zero-Emissions Vehicle (ZEV) Programs?  Established in CA, MA, ME, NY, & VT  Offer rebates, tax incentives, closer parking, use of special HOV type lanes for ZEVs  Types of ZEVs: ◦ Electric cars- plug in to recharge ◦ Hybrid cars- run on both gas and electric ◦ Methanol fuel cell cars
  15. 15. What are Industrial Air Pollutants?  Any industry or power plant that burns fuel to produce energy  Power plants produce ◦ 2/3 of all SO2 emissions ◦ 1/3 of all NOx emissions  VOCs are common type ◦ From dry cleaning fumes
  16. 16. What are Industrial Air Pollutants?  Clean Air Act requires one of the following: ◦ Scrubbers installed in smoke stacks to control air pollution  Gases move through spray of water that dissolves the pollutant ◦ Electrostatic Precipitators  Use static electricity to attract particulates from burning of fossil fuels
  17. 17. What is smog?  Air pollution that hangs over urban areas and reduces visibility.  Car exhaust reacts with air & sunlight to make ground level ozone.  Ozone reacts with more car exhaust to make smog.  Smog in Beijing, China (~2min)
  18. 18. What is a Temperature Inversion?  Circulation keeps air pollution from reaching dangerous levels.  If a warm air mass traps a cool air mass it will trap pollution with it.  Usually common in cities surrounded on 3 sides by mountains.  Mountains trap the air.  Donora, PA (1948)- 18 people died when temperature inversion trapped SO2 & HF pollution being released from a local steel mill.
  19. 19. You should be able to…  Name 5 primary pollutants & give important sources for each.  Name the 2 major sources of air pollution in urban areas.  Describe the way in which smog forms.  Define the term temperature inversion. Explain how temperature inversion traps pollutants near Earth’s surface.

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