1. Air Pollution

2. The Atmosphere as a Resource
Atmospheric composition:
Nitrogen = 78%
Oxygen = 21%
Argon = 0.93%
Carbon dioxide = 0.04%

3. The Atmosphere as a Resource
Name the 4 major gaseous components of the earth’s atmosphere.
Describe 2 ecosystem services that the atmosphere provides.

4. Air Pollution What do you know? What is outdoor air pollution?
What do you think causes outdoor air pollution?
Where does air pollution come from?
Have you ever seen air pollution? How do you know?
Is air pollution a solid, liquid or a gas?
Do you think humans are affected by air pollution? How?

5. Air Pollution
What else do you think might be affected by air pollution?
How do we get rid of air pollution?
Have you heard of ozone? Is it good or bad? Explain.
Have you heard about particle pollution before?
Do you think particles floating in the air affect humans? How?
How do particles get into the air?

6. Types of Air Pollution
Air Pollution – various substances added to the atmosphere by natural events and human activities in high enough concentrations to cause harm to humans, other organisms, or materials
Primary air pollutant – a substance emitted directly to the atmosphere
Secondary Air Pollutant – a substance formed in the atmosphere as a result of reactions involving primary pollutants

7. Types and Sources of Air Pollution
Primary and Secondary Air Pollutants

8. Types and Sources of Air Pollution
Major Classes of Air Pollutants
Particulate matter
Nitrogen oxides
Sulfur oxides
Carbon oxides
Hydrocarbons
Ozone
Lead
Ozone damage

9. Types and Sources of Air Pollution
Major Air Pollutants

10. Types and Sources of Air Pollution
Learning Objective: 1. Describe the difference between a primary and secondary air pollutant and give examples of each.

11. Types of Air Pollution
Particulate Matter – solid and liquids suspended in the atmosphere.
Soil, Soot, lead, asbestos, sea salt, sulfuric acid droplets
Reduces visibility
Corrodes structures
Leaves residue on surfaces
Can absorb other toxic substances

12. Types of Air Pollution Nitrogen oxides- NO, NO2, N2O
Produced by the reaction at high temperatures between N2 and O2
Inhibit plant growth
Aggravate respiratory conditions
Involved in the production of photochemical smog
N2O is a greenhouse gas and is involved in ozone depletion
Corrode metals and textiles

13. Types of Pollution Sulfur oxides – SO2, SO3
formed mainly when sulfur containing fuels are burned (mainly coal)
Dissolve in water to form sulfuric acid (acid rain), which damages plants and structures
Damage plants
Respiratory irritants

14. Types of Pollution Carbon Monoxide – CO
Produced by the incomplete combustion of hydrocarbons
Poisonous gas

15. Types of Pollution Hydrocarbons-compounds containing H and C
Wide variety of compounds
Involved in the production of photochemical smog.
Some are toxic (respiratory irritants, cancerous)
Some are involved in ozone depletion
Methane (CH4) is a potent greenhouse gas.

16. Types of Pollution Ozone – O3
Essential component of the stratosphere that blocks UV light waves from the sun
Harmful component of photochemical smog in the troposphere.
A secondary pollutant formed by reactions between nitrogen oxides and hydrocarbons, initiated by sunlight
Reduces visibility and causes health problems; damage to plants

17. Effects of Air Pollution
Damages organisms
Reduced visibility
Corrodes materials
Especially harmful to the respiratory systems of humans
Reduction in crop productivity
Leads to acid deposition
Global climate change
Stratospheric ozone depletion

18. Effects of Air Pollution
Air Pollution and Human Health
Air Toxics – a variety of hazardous air pollutants; it is estimated that 360 out of 1 million Americans die of cancer every year as a result of air toxics.

19. Effects of Air Pollution
Effects of air pollution on children:
Air pollution can restrict lung development in children making them more susceptible to respiratory and heart problems later in life.
Children have a higher metabolic rate, meaning they breathe in more air than adults.

20. Controlling Air Pollution in the United States
Clean Air Act
Emissions in the US, 1970 vs. 2000

21. Controlling Air Pollution
Energy efficiency and conservation are important
Smokestacks are equipped with electrostatic precipitators, scrubbers, filters, etc. to remove particulates, sulfur oxides, and nitrogen oxides
Controlling the fuel/air ratio and lowering combustion temperatures leads to the production of less nitrogen oxides
Modifications to furnaces and combustion engines to provide more complete combustion eliminates carbon monoxide and hydrocarbon emissions.

22. Controlling Air Pollution in the United States
Turned OFF
Controlling Air Pollutants
Turned ON
Electrostatic precipitator

23. Controlling Air Pollution in the United States
Turned OFF
Controlling Air Pollutants
Turned ON
Electrostatic precipitator

24. Controlling Air Pollution
Clean Air Act
passed in 1970; amended in 1977 and 1990
Administered by the EPA
States pass laws which must be as stringent as the federal law
Focuses on six air pollutants (lead, particulates, sulfur dioxide, carbon monoxide, nitrogen oxides, ozone)

25. Controlling Air Pollution in the United States
US Urban Areas with Worst Air Quality, 2002

26. Controlling Air Pollution
Clean Air Act
Areas which do not meet regulatory requirements for the six pollutants are designated as nonattainment areas
1977 and 1990 amendments required stricter controls on automobile emissions.
1990 amendments also focused on regulation of air toxics; required a 90 % reduction in emissions of 189 toxic chemicals