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 Earth’s surface up to 11 miles high
Stratosphere  upper atmosphere; extends 11 to 30 miles above the Earth’s surface
Troposphere:
-most of the air is composed of nitrogen (78%) and oxygen (21%)
-contains 75-80% of Earth’s air
Stratosphere:
-similar in composition to troposphere except it contains much less water vapor and higher levels of ozone

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
Air pollution:
-can come from both natural (ex: forest fires, volcanoes) and human sources (ex: burning fossil fuels)
Primary pollutant:
-example: carbon monoxide
Secondary pollutant:
-example: ozone

5. Sources and Types of Air Pollutants
Primary Pollutants CO
CO2
Secondary Pollutants
SO2 NO
NO2
SO3
Most hydrocarbons
HNO3
H2SO4
Most suspended
particles
H2O2 O3
PANs
SO4 2 –
Most
NO3 –
and
salts
Sources
Natural
Stationary
Mobile
Fig. 15-3, p. 348

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 F. Lead
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 (NOx) 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)
- The hotter the day, the higher the level of smog!
Since 1990, levels of this type of smog has increased 2 to 8 times
Origins are automobile exhaust and coal-burning power and industrial plants
Most common in cities with warm, sunny, dry climates with lots of motor vehicles/industry
Ex: LA, Denver and Salt Lake City

11. Animation
Formation of photochemical smog

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
Tall smoke stacks and pollution control mechanisms in developed countries have greatly reduced this type of air pollution.
- BUT still a major problem in developing countries, like China and India.

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
Results:
respiratory diseases and premature deaths
Prevents up to 15% of sunlight from reaching the ground
Changing weather patterns
Negatively affects western U.S. air quality
As much as 10% of air pollutants in LA comes from SE Asia!!!

16. Smog Factors Influencing Smog Formation: Local Climate/Topography
Population Density
Amount of industry
Type of fuels consumed
Local climate/topography:
-winds and rain/snow reduce the level of smog
-hills/mountains, urban buildings and high temperatures can increase it
Population density:
-more people=more smog
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
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 (www.dep.state.fl.us/Air)
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.
U.S. govt investigated the effects of acidic deposition in over 1000 lakes larger than 10 acres and in thousands of miles of streams believed to be sensitive to acidification.
- of these, acid rain caused acidity in 75% of the acidic lakes and 50% of acidic streams
- several “hot spots” include Adirondacks and Catskill Mtns in New York, the mid-Appalachian highlands along the east coast, the upper midwest, and mountainous areas of the western U.S.
- one of the most acidic lakes reported was Little Echo Pond in Franklin, NY, which had a pH of 4.2

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
Trees:
- Acid rain has been implicated in forest and soil degradation in many areas of the eastern U.S., particularly high elevation forests of the Appalachian Mtns from Maine to Georgia that includes areas such as the Shenandoah and Great Smoky Mtn NP
Reduced visibility:
- The U.S. govt’s Acid Rain Program is expected to improve the visual range in the eastern U.S. by 30%
- The visual range improvements expected at national parks of the eastern U.S. due to the Acid Rain Program’s SO2 reductions will be worth over a billion dollars annually by the year 2010.

24. Tree Damage from Acid Deposition
Mt. Mitchell, NC – the highest point east of the Mississippi
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 NOx emissions, and maintain all vehicles well.

26. Reducing Acid Deposition
© 2006 Brooks/Cole - Thomson
Solutions
Acid Deposition
Prevention
Cleanup
Reduce air pollution by improving energy efficiency
Add lime to neutralize
acidified lakes
Reduce coal use
Add phosphate
fertilizer to neutralize
acidified lakes
Increase natural gas use
Increase use of
renewable resources
Burn low-sulfur coal
Remove SO2 particulates, and Nox from smokestack gases
Remove Nox from motor vehicular exhaust
Tax emissions of SO2
Fig , p. 357

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

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
Formaldehyde:
EPA estimates that one out of every 5,000 people living in a manufactured home for more than 10 yrs will develop cancer from formaldehyde exposure!
Radon:
EPA recommends that all homes be tested for radon
Second leading cause of lung cancer
One in 15 homes in the U.S. has a high level of radon

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

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
In US, the EPA estimates that annual deaths related to indoor and outdoor air pollution range from 150,000 to 350,000 people.
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
- Established NAAQS (National Ambient Air Quality Standards) for six major pollutants which specifies the maximum allowable level for each.
- Also established emission standards for more than 188 hazardous air pollutants.
- These acts have helped to greatly improve air quality in the U.S. but many people are still living in dangerously polluted areas.

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
Prevention:
-the 97% reduction in lead between 1970 and 1998 was due to the ban on leaded gasoline
2-cycle engines:
A 1-hr ride on a typical jet ski creates more air pollution than the average car does in a year!

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!!!
If they use less than their limit, then they can use the credits for their own benefit (e.g., expand the size of a plant or offset the pollution at another plant) or sell them to other groups (e.g., private utilities, environmental groups).
This policy has reduced sulfur dioxide emissions in the U.S. by 30% between 1994 and 1997!

36. Other Solutions Figures 15-17 through 15-21 Individual Actions:
Use mass transit
Bike/walk when possible
Use fuel efficient vehicles
Don’t 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
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