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476 Chapter 15 • Study Guide

Lesson 1 earth’s atmosphere•   Properties of the atmosphere include its composition, 

relative humidity, temperature, and air pressure. •   Relative humidity is the ratio of water vapor the air 

contains to the maximum amount it could have at that temperature. Air pressure is the force exerted by air on the area below it. 

•   The main layers of the atmosphere include the tropo-sphere, stratosphere, mesosphere, and thermosphere. Movement of air within the troposphere is largely respon-sible for weather. 

•   The stratosphere, the layer above the troposphere, con-tains the ozone layer. 

•   Processes that affect weather in the troposphere include heat transfer and the interaction of air masses.

atmosphere (452) thermosphere (456) relative humidity (454) radiation (458) air pressure (455) conduction (459) troposphere (455) convection (459) stratosphere (456) convection current (459) ozone layer (456) air mass (460) mesosphere (456) front (460)

Lesson 2 pollution of the atmosphere•   Air pollution can be caused by natural processes such as 

dust storms and human activities such as the combustion of fossil fuels.

•   Air pollutants can damage the respiratory system, inter-fere with the body’s uptake of oxygen, and cause cancer.

•   Temperature inversions may trap smog and prevent the pollutants from dispersing.

•   Acid deposition results when products of combus-tion combine with water and other substances in the atmosphere.

air pollution (462) secondary air pollutant (463) emission (462) smog (465) fossil fuel (462) temperature inversion (466) primary air pollutant (463) acid deposition (467)

Lesson 3 Controlling air pollution•   The Clean Air Act has provisions that have reduced air 

pollution in the United States. For example, the Act limits the emissions of pollutants and sets standards for air quality.

•   The ozone hole is the area of lowered ozone concentra-tion over Antarctica that occurs every year from August to October. Nations have taken steps to deal with the problem of ozone loss in the stratosphere.

•   The Montreal Protocol is an international treaty that has dramatically reduced production of CFCs, the chemicals linked to the development of the ozone hole. Evidence indicates that the ozone layer is beginning to recover.

Clean Air Act (470) catalytic converter (471) scrubber (472) ozone hole (472) chlorofluorocarbon (CFC) (472) Montreal Protocol (473)

InquIry LABs And ActIvItIes• Acid Rain and Seeds   At what point does acidity in precipitation cause prob-

lems? Test vinegar-water dilutions to see how acidity affects seed growth.

• What’s in the Air?   Build an air trap and take it outside to capture particles 

in the air. Observe the particles under magnification to infer their source.

• Using Your UV Index   Checking your forecast involves more than just rain or 

shine. Monitor the UV index and see what protections the EPA recommends.

Lesson 2 What are the sources

of air pollution?

Lesson 1 How can we describe Earth’s atmosphere?

Lesson 3 What measures can limit

and prevent pollution of the atmosphere?

How can we ensure everyone has clean

air to breathe?

STUDY RESOURCES

Chapter 15 Self Test • Chapter 15 Worksheets • Chapter 15 Overview Presentation (for PowerPoint)

The Atmosphere 477

Review Concepts and Terms 1. Which of the following identifies the layers of the

atmosphere in correct order, beginning with the lowest layer?

a. mesosphere, thermosphere, stratosphere, troposphere

b. thermosphere, stratosphere, troposphere, mesosphere

c. troposphere, stratosphere, mesosphere, thermosphere

d. troposphere, mesosphere, thermosphere, stratosphere

2. A boundary along which a mass of warm, moist air replaces a mass of cool, dry air is called a(n)

a. air front. c. cold front. b. warm front. d. convection front.

3. Carbon-containing fuels that formed from the remains of living things are called

a. fossil fuels. c. soot. b. emissions. d. smog.

4. Which of the following is the method of heat transfer shown by the arrows in the diagram below?

a. radiation c. conduction b. convection d. inversion

5. Which of the following is NOT a primary air pollutant?

a. particulate matter b. lead c. carbon monoxide d. sulfuric acid

6. Acid deposition is caused mainly by a. dust storms. b. volcanoes. c. burning fossil fuels. d. ozone.

7. A scrubber is a device that a. prevents temperature inversions. b. removes pollutants or changes them chemically

before they are released by factories. c. reduces the amount of pollutants released by

motor vehicles. d. removes lead from gasoline.

8. The main chemicals responsible for the ozone hole are

a. sulfuric acid and nitric acid. b. volatile organic compounds. c. carbon monoxide and carbon dioxide. d. chlorofluorocarbons.

Modified True/FalseWrite true if the statement is true. If it is false, change the underlined word or words to make the statement true.

9. The force exerted by air on the area below it is called air pressure.

10. The troposphere provides living things with oxygen.

11. Industrial smog is a haze formed when sunlight acts on air pollutants.

12. Lead can bond to hemoglobin and therefore deprive the body of oxygen.

13. As a result of the Montreal Protocol, manufacture of CFCs has fallen dramatically.

Suppose you live in a city that is going to enact a congestion-charging plan similar to London’s. You are on a committee to convince commuters that they and other citizens will benefit from the plan. Write a brochure or design a poster to convey this information.

ANSWERS

Chapter Assessment For answers to the Chapter Assessment, see page A–24 at the back of the book.

15Cha

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478 Chapter 15 • Assessment

Short Answer 17. How has the amount of oxygen in Earth’s

atmosphere changed over time? What has caused this change?

18. In the troposphere, what is the relationship between air temperature and the height above Earth?

19. What is relative humidity? 20. Describe one natural process that causes air

pollution. 21. What is the difference between primary air

pollutants and secondary air pollutants? 22. How do air pollutants contribute to emphysema,

asthma, and other respiratory conditions? 23. Identify two ways in which acid deposition can

harm ecosystems. 24. List three provisions of the Clean Air Act.

Critical Thinking 25. Compare and Contrast Contrast the effects of

stratospheric ozone and tropospheric ozone on people’s health.

26. Relate Cause and Effect Pollutants generally stay in the stratosphere for a long time. What effect might this characteristic have on the ozone layer?

27. Infer Why does it often take a long time for a temperature inversion to end?

28. Compare and Contrast Compare industrial smog and photochemical smog. How are these two types of smog similar? How are they different?

29. Sequence Describe the sequence of events that led to the Montreal Protocol.

30. Draw Conclusions Why is it often difficult for individual states to prevent acid deposition from falling within their boundaries?

31. Propose a Solution Suppose a city government wants to start a congestion-charging program similar to London’s. However, businesses are fearful of losing money if shoppers are discour-aged from going downtown because of the charge. Think of a solution that would keep the congestion-charging program and still encourage shoppers to visit downtown stores.

Reading ComprehensionRead the following selection and answer the questions that follow.After World War II, thousands of families moved into Los Angeles and its suburbs. New neighborhoods were springing up, replacing orange groves and open space. Roads and schools were quickly built to keep pace with the rapid population growth. Surrounded by beautiful mountains, the entire Los Angeles basin looked like a new, green, sun-filled paradise to the families moving there.

In the early 1950s, one of the common family chores in Los Angeles was to carry the trash out to the stone incinerator behind the garage, where each family burned its dry trash. “Wet” garbage was collected and taken to the city dump, where it was burned by the city. Everyone throughout the city either used an incinerator or burned things in an open trash pile. There were more than 400,000 back-yard trash incinerators. On warm afternoons, peo-ple’s eyes would sometimes sting and burn. People would stop, close their eyes, and let the cleansing tears refresh irritated eyes. They accepted this as a normal part of life in suburban Los Angeles.

14. Which of the following would be the BEST title for the selection above?

a. “The Mountains of Los Angeles” b. “Traffic Problems in Los Angeles” c. “Burning Trash, Burning Eyes” d. “The Lost Orange Groves”

15. Which of the following statements is true about trash in Los Angeles in the early 1950s?

a. All trash, both wet and dry, was burned. b. Only dry trash was burned. c. All trash was burned in incinerators. d. No trash was burned at the city dump.

16. According to this selection, what made people’s eyes burn?

a. dust storms caused by erosion b. pollutants released by burning trash c. pollutants released by cars and trucks d. warm weather

Ecological Footprints

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140

120

100

80

60

40

20

0

20

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601980 1995 2000 2005 2008

Year

Reduction of Air Pollutants vs.Increase in Energy Consumption

Data from U.S. EPA.

Vehicle miles traveledEnergy consumptionPopulationTotal emissions

91%

34%

29%

54%

You

Your class

Your state

UnitedStates

1

Total Emissionsof Nitrogen Oxides (pounds)

PopulationSource Nitrogen Oxide Emissions From Vehicles(pounds)

The Atmosphere 479

According to EPA data, emissions of nitrogen oxides in the United States in 2008 totaled 16.3 million tons. Nitrogen oxides come from many sources, but 9.5 million tons come from motor vehicles. In 2008, the population of the United States was about 304.1 million people. Use this information to calculate the missing values in the table for the year 2008. (Hint: 1 ton = 2000 pounds) 1. On the basis of the 2008 data, how many

pounds of emissions would be saved per person if driving were reduced by one half?

2. What percentage of the total emissions per person would that be?

3. How might a driver reduce his or her driving by one half?

34. Interpret Graphs Which changed more, vehicle miles traveled or energy consumption?

35. Analyze Data On the basis of change in vehicle miles traveled, population, and energy consump-tion, how would you expect emissions to change during that period? Explain your answer.

36. Draw Conclusions What do you think accounts for the way that the amount of emissions changed?

Write About It 37. Form an Opinion In the area in which you live, is

using public transportation a good way to reduce air pollution? Support your answer with informa-tion about your area.

38. Creative Writing Sherwood Rowland and Mario Molina won the Nobel Prize for their work in identifying CFCs as the cause of ozone depletion. Suppose you are on the committee overseeing the awards ceremony. Write a speech that you might give explaining why Rowland and Molina are receiving the award.

39. Apply the BIGQUESTION Draw and label a diagram showing how your school or com-munity might take steps to reduce emissions of pollutants.

Analyze DataThe graph shows how several factors related to emission of pollutants changed between 1980 and 2008. Use the data plotted on the graph to answer the questions.

32. Interpret Graphs Between 1980 and 2008, which of the factors plotted on the graph increased?

33. Interpret Graphs During the same period, how did emissions change?