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Environmental Science Chapter 12 Air Pollution. Key Concepts Structure and composition of the atmosphere Types and origins of major outdoor air pollutants.

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Presentation on theme: "Environmental Science Chapter 12 Air Pollution. Key Concepts Structure and composition of the atmosphere Types and origins of major outdoor air pollutants."— Presentation transcript:

1 Environmental Science Chapter 12 Air Pollution

2 Key Concepts Structure and composition of the atmosphere Types and origins of major outdoor air pollutants Two types of smog Acid deposition and how it can be reduced Harmful effects of air pollutants Preventing and controlling air pollution

3 Reminders… Troposphere lower atmosphere; extends from the Earths surface up to 11 miles high Stratosphere upper atmosphere; extends 11 to 30 miles above the Earths surface

4 Outdoor Air Pollution Def: presence of one or more chemicals in the atmosphere in sufficient quantities and duration to cause harm to humans or other living organisms Primary vs Secondary Pollutants –A. Primary those emitted directly into the troposphere in a potentially harmful form –B. Secondary formed when primary pollutants react with one another or other components of air

5 Primary Pollutants Secondary Pollutants SourcesNatural Stationary COCO 2 SO 2 NONO 2 Most hydrocarbons Most suspended particles SO 3 HNO 3 H 2 SO 4 H2O2H2O2 O3O3 PANs MostandsaltsNO 3 – Mobile SO 4 2 – Fig. 15-3, p. 348 Sources and Types of Air Pollutants

6 Outdoor Air Pollution Cities normally have higher air pollution than rural areas but winds can transport pollutants to these areas United States has government-mandated standards for maximum allowable atmospheric concentrations for six major pollutants Acid Rain Poland

7 Outdoor Air Pollution (Table 15-1) A. Carbon Monoxide –Sources: smoking/burning of fossil fuels –Health Effects: reduce ability of red blood cells to carry oxygen; negatively impact the development of fetuses/young children; aggravate existing healthy conditions; cause headaches/nausea B. Nitrogen Dioxide –Sources: burning of fossil fuels –Health Effects: cause irritation/damage to lungs; increase susceptibility to respiratory diseases; aggravate existing lung disorders such as asthma –Environmental Effects: can form nitric acid in atmosphere which is a major component of acid rain; may reduce visibility

8 Outdoor Air Pollution C. Sulfur Dioxide –Sources: burning of fossil fuels –Health Effects: cause breathing problems and bronchitis-like condition; aggravate asthma symptoms –Environmental Effects: can form sulfuric acid in atmosphere, another component of acid rain D. Suspended Particulate Matter (SPM) –Sources: burning of fossil fuels, agriculture, unpaved roads, construction –Health Effects: cause respiratory irritation/bronchitis; aggravate existing respiratory conditions; lead to early death, cancer or mutations depending on chemicals contained within (ex: lead)

9 Outdoor Air Pollution E. Ozone –Sources: chemical reaction with volatile organic compounds and nitrogen oxides –Health Effects: cause respiratory irritation; aggravate existing respiratory conditions; suppress immune system F. Lead –Sources: paint, metal refineries, storage batteries, leaded gas, etc. –Health Effects: damage to brain and nervous system; cancer; mental retardation

10 Smog Two Types: –A. Photochemical (Brown) Smog Pollutants formed with the aid of sunlight Forms when nitrogen oxides (NO x ) and volatile organic compounds (VOCs) react with UV light Mixture of >100 chemicals but the most abundant of these is ozone (termed ground- level ozone)

11 Formation of photochemical smog Animation

12 Los Angeles

13 Smog – B. Industrial (Gray) Smog Consist mostly of sulfur dioxide, sulfuric acid droplets and aerosols Found in cities with industries that burn a lot of fossil fuels

14 Industrial Smog in India Fig. 15-5, p. 351

15 Asian brown cloud can be up to a three kilometres thick and stretches from India to Western Pacific –Causes: Asia's explosive industrial development Sources include: vehicular and industrial emission, burning of millions of little cookers in peoples' homes, burning wood or dung

16 Smog Factors Influencing Smog Formation: 1.Local Climate/Topography 2.Population Density 3.Amount of industry 4.Type of fuels consumed So, because Florida has a low topography, good air circulation, high humidity, and lots of rain, smog is rarely a problem here!

17 Air Pollution Website depicts the air quality index (AQI) for select cities or locations throughout the United States –EPA calculates the AQI for five major air pollutants regulated by the Clean Air Act: ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide, and nitrogen dioxide. –Symbolized by color: 0 to 50 Good Green Yellow 51 to 100 Moderate Yellow 101 to 150 Unhealthy for Sensitive Groups Orange 151 to 200 Unhealthy Red 201 to 300 Very Unhealthy Purple 301 to 500 Hazardous Maroon

18 Air Quality - Florida Florida DEP website ( –Contains air quality information for different cities and counties in Florida –Osceola County From 2001 to 2003 for Ozone: –97.6% of days were good (green) –2.2% of days were moderate (yellow) –0.2% of days were unhealthy for sensitive groups (orange)

19 Acid Deposition Primary pollutants are sulfur dioxide and nitrogen oxides which can react with other atmospheric compounds to produce acidic substances that can remain in the atmosphere for up to two weeks! Acidic substances can descend to the Earth in two forms: –A. Wet ex: rain, snow, fog –B. Dry shorter time frame (<3 days)

20 Acid deposition

21 pH Measurements at US Sites Fig. 15-7, p. 354

22 Acid Deposition Effects: –1. Respiratory problems in humans –2. Damages property –3. Lakes and Streams Acid rain causes a cascade of effects that harm or kill individual fish, reduce fish population numbers, completely eliminate fish species from a waterbody, and decrease biodiversity.

23 Acid Deposition –4. Trees acid rain causes slower growth, injury, or death of forests. –5. Corrosion of metals (such as bronze) and the deterioration of paint and stone (such as marble and limestone). –6. Reduced visibility

24 Tree Damage from Acid Deposition Fig , p. 356

25 Acid Deposition Obviously, the best approach to reduce acid rain is to reduce emission of the chemicals that cause it (sulfur dioxide and nitrogen oxides) What you can do (EPA): –Turn off lights, computers, and other appliances when you're not using them –Use energy efficient appliances: lighting, air conditioners, heaters, refrigerators, washing machines, etc. –Only use electric appliances when you need them. –Keep your thermostat at 68 F in the winter and 72 F in the summer. You can turn it even lower in the winter and higher in the summer when you are away from home. –Insulate your home as best you can. –Carpool, use public transportation, or better yet, walk or bicycle whenever possible –Buy vehicles with low NO x emissions, and maintain all vehicles well.

26 © 2006 Brooks/Cole - Thomson Reduce air pollution by improving energy efficiency Reduce coal use Increase natural gas use Increase use of renewable resources Burn low-sulfur coal Remove SO 2 particulates, and No x from smokestack gases Remove No x from motor vehicular exhaust Tax emissions of SO 2 Add lime to neutralize acidified lakes Add phosphate fertilizer to neutralize acidified lakes Solutions Acid Deposition Prevention Cleanup Fig , p. 357 Reducing Acid Deposition

27 Fig , p. 358 Chloroform Benzo- -pyrene Styrene Radon-222 Methylene Chloride Tobacco Smoke Carbon Monoxide Asbestos Nitrogen Oxides 1, 1, 1- Trichloroethane Major Indoor Air Pollutants Particulates FormaldehydeTetrachloro-ethylene Para-dichlorobenzene

28 Indoor Air Pollution Most Dangerous: –A. Formaldehyde colorless gas used in the manufacturing of many common household materials, such as furniture, drapes, plywood, and paneling –B. Radon Gas colorless, odorless gas that is found naturally in underground deposits of minerals (e.g., uranium, phosphate) and seeps up through the soil and into homes via cracks, openings or through concrete blocks

29 Fig , p. 359 Outlet vents for furnaces and dryers Slab joints Wood stove Cracks in floor Clothes dryer Furnace Radon-222 gas Slab Soil Uranium-238 Sump pump Cracks in wall Open window Openings around pipes Openings around pipes Radon

30 Effects of Air Pollution Humans: –Break down natural defenses and lead to respiratory diseases such as lung cancer, asthma, chronic bronchitis and emphysema Plants: –Forest diebacks (due to depletion of nutrients in soil and increased susceptibility to pests and diseases) –Estimated $2-6 billion in agricultural losses due to air pollution (mainly ozone)

31 Effects of Air Pollution Other: –Deterioration of paint on cars/houses –Damage to historical buildings, sculptures, etc. –Cleaning costs due to soot/other particulates accumulating

32 Premature US Deaths from Air Pollution Fig , p. 361

33 Solutions Clean Air Acts of 1970, 1977 and 1990 –Federal government established air pollution regulations –EPA was the agency charged with developing and enforcing air regulation standards

34 Solutions Improvements still needed: –Focus more on prevention than clean-up –Increase fuel efficiency standards for automobiles, especially SUVs and trucks –Better regulation of emissions from 2-cycle engines (e.g., outboard motors, jet skis, lawnmowers, chainsaws) –Do more to decrease emission of greenhouse gases –Indoor air pollution control –Better enforcement

35 Emission Trading Policy Sulfur Dioxide Emissions –Each year a power plant is given a certain number of pollution credits to emit a certain amount of sulfur dioxide. –You can even buy credits!!!

36 Other Solutions Figures through Individual Actions: –Use mass transit –Bike/walk when possible –Use fuel efficient vehicles –Dont smoke indoors or in confined areas –Increase ventilation and intake of outside air –Install energy efficient appliances –Use less polluting substitutes for cleaning agents, paints, etc. Outdoor Indoor

37 Websites Some alternatives to common pesticide chemicals/cleaners: More information on air pollution: Facts about alternative fuels:

38 Any Questions? News stories… Algal Fuel Transgenic Tobacco

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