1. Air
Chapter 12

2. Food for thought
Humor is often used to get people’s attention. With your neighbor, use humor to complete the following sentence to draw attention the air pollution problem.
You know the air is polluted when….
“I thought I saw a blue jay this morning. But the smog was so bad, it turned out to be a cardinal holding its breath.”
Michael J. Cohen

3. Section 12-1: What Causes Air Pollution?
Discussion Prompt: List 5 things you think cause air pollution.

4. What is in air? Mixture of gases
78% nitrogen
21% oxygen
1% argon, carbon dioxide, water vapor
Pollutants: harmful materials that enter the environment and are picked up by air currents

5. Air pollution
Air pollution: collection of harmful substances released into the atmosphere
Some from natural sources-sand, dust storms, volcanic eruptions, forest fires
Human activity = major source of pollutants that continues to grow
Notice on map that
areas with a lot of air
pollution (red) are near
large cities

6. History of air pollution
Industrial revolution 1700’s – dependent on burning of wood and coal for fuel
Elevated air pollution to a widespread status
Illness and death due to air pollution sky rocketed

7. Primary and secondary air pollutants
Primary pollutants: put directly into the air by humans (smoke, industrial wastes on p. 326)
Secondary pollutants: primary pollutants react with other substances in the air (ground-level ozone created when UV rays of the sun cause oxygen to react with automobile emissions)

8. Outdoor pollutants
Particulates: tiny solids suspended in the air (Examples: ash, dust, soot, plant pollen)
Can be inhaled and become trapped in the lungs
Gases – usually oxides – compounds of oxygen and another element
Released when fossil fuels are burned

9. Photochemical smog – yellow brown haze formed when sunlight reacts with pollutants from cars
Example: Ozone (O3) very corrosive, nitrogen dioxide – brown gas, methane – from livestock and decaying matter
Chlorofluorocarbons (CFC’s): compounds of chlorine, fluorine, and carbon once used in refrigerators, ac’s, aerosol cans, and the production of foams

10. Indoor Pollutants
Indoor Pollutant effects are multiplied by poor air circulation and the long amounts of time people spend inside
Cigarette smoke – deadliest of all
Microorganisms – bacteria and fungi from air ducts and vents
Radon – colorless, odorless, radioactive gas – comes from soil when radium breaks down
Asbestos – minerals that form in long thin fibers – banned in US

11. Temperature Inversions
Read about temperature inversions on p. 330.
Describe temperature inversions.

12. Section 12-2: Air, Noise, and Light Pollution
Discussion Prompt: What do you think light and noise pollution are?

13. Air pollution and living things
Pollution linked to many health problems and can worsen existing medical conditions
Carbon monoxide – binds to hemoglobin in oxygen’s place and can cause death
Ozone and oxides – irritate eyes and respiratory tract
Emphysema – disease in which tiny air sacs in the lungs break down
Lung Cancer – 150,000 deaths per year in US

14. How does air pollution effect an ecosystem?
Ozone and sulfur oxides – hazardous to plants, cause stems to be brittle and leaves spotted
US loses $10 million of crops per year due to air pollution
Loss of plants disrupts the food web and deprive animals of food
Same health problems for animals as for humans (cancer, lung irritation, etc.)
Smog: when air pollution hangs over urban areas and reduces visibility
Temperature Inversions: usually warm air rises and takes pollutants up into atmosphere (see p. 330)
Sometimes the air near the ground is colder than the air above
Pollutants become trapped near the surface of the ground
Example: Los Angeles – cities in valleys

15. Controlling Air Pollution
Natural controls – precipitation is most effective
particles in air stick to precip and fall to the ground
many aerosols dissolve in rain
CO2 removed biologically by plants and microorganisms, also removed by ocean waters (cooler temps hold more)

16. Human controls –
Emission control standards for automobiles
catalytic converters remove pollutants from exhaust
Use unleaded gas, cars get better gas mileage than in past (reduce lead pollution by 90%)
Will always put out some pollution when gas is burned
Electric cars, hybrid cars
Zero Emissions Vehicles – no tailpipe emissions

17. Human Controls, cont. Legislation (EPA)– Clean Air Act 1970
Requires pollution control devices in factories
Regulates vehicle emissions
Power plants – Burn fossil fuels to produce electricity
use techniques to remove pollutants from exhaust
Scrubbers: machine that moves gases through a spray of water that removes many pollutants

18. Noise Pollution Noise pollution: Unwanted sound
Comes from airplanes, machinery, loud concerts, etc.
Causes annoyance, stress, hearing loss
Living things harmed by loud or high-pitched sounds
Sound measured in decibels
70-80 dB = annoyance, hearing loss
120 – 130 dB = physical pain and hearing damage
Noise Control Act 1972 – sets standards for maximum noise levels in workplace

19. Light Pollution Does not present a direct hazard to human health
Diminishes our view of the night sky
Energy often wasted
When lights are pointed upward (billboards, buildings)
Poor quality street lights
Can be minimized by using time controls

20. Section 12-3: Acid Precipitation
Discussion Prompt: How have you been affected by acid rain?

21. Acid Rain Acid rain: precipitation that is more acidic than normal
Normal precip = 5.6 pH
Water in the atmosphere reacts with sulfur and nitrous oxide to form nitric acid and sulfuric acid
Strong and corrosive
Falls on forests and accumulates in mtn. lakes making them uninhabitable by fish
Absence of aquatic life disrupts ecosystems
Damages trees and destroys forests

22. International Conflict and Cooperation
Acid rain can be released in one area and fall in another
half of acid rain that falls in SE Canada results from pollution created in the NE United States
Signed the Canada-US Air Quality Agreement in 1991 to reduce emissions in both countries
See map on p. 339
China burns large amounts of high-sulfur coal that creates acid rain that falls throughout Asia