Lesson 4 | Air Quality
Name Date Class
LESSON 4: 20 minutes
How does acid rain form?
Vehicles, factories, and power plants release chemicals into the atmosphere. When these
chemicals combine with water vapor, they can form acid rain.
Procedure
1. Read and complete a lab safety form.
2. Half-fill a plastic cup with distilled
water.
3. Dip a strip of pH paper into the
water. Use a pH color chart to
determine the pH of the distilled water.
Record the pH in your Science Journal.
4. Use a dropper to add lemon juice
to the water until the pH equals that
of acid rain. Swirl and test the pH each
time you add 5 drops of the lemon
juice to the mixture.
Think About This
1. A strong acid has a pH between 0 and
2. How does the pH of lemon juice
compare to the pH of other substances?
Is acid rain a strong acid?
2. Key Concept Why might scientists monitor the pH of rain?
64 Earth’s Atmosphere
Name Date Class
LESSON 4
Air Quality
Directions: Use the clues and the terms listed below to complete the puzzle. NOTE: There is no empty square in
the puzzle between the words of two-word terms.
|acid precipitation |air pollution |particulate matter |photochemical smog |
Clues
Across
2. results from an interaction of sunlight
and chemicals in the air
3. rain that results from sulfur dioxide
and nitrogen oxide combining with
moisture in the atmosphere
4. a type of air pollution that consists of
chemicals and dust
Down
1. includes the components smog and
particulates
Earth’s Atmosphere 65
Name Date Class
LESSON 4
Air Quality
A. Sources of Air Pollution
1. is the contamination of air by harmful substances
including smoke and other gases.
a. Air pollution harms animals and humans by weakening the
and causing disease.
b. Air pollution plants, including crops, and can reduce
food production.
2. is pollution that comes from an identifiable source.
A natural source of this pollution is a(n) .
3. is pollution that comes from a widespread area.
A natural source of this pollution is .
B. Causes and Effects of Air Pollution
1. forms when sulfur dioxide and nitrogen oxides
combine with moisture in the atmosphere and create precipitation that has a pH
lower than that of normal rain water.
a. Acid precipitation falling in lakes and rivers can harm
living in the water.
b. Acid precipitation can buildings that are made of
stone.
c. One of the most common sources of pollutants that cause acid rain
is .
2. is air pollution that forms from the interaction between
chemicals in the air and sunlight.
a. Smog forms when from gasoline mixes with sunlight.
b. is the main gas in smog; at ground level, this gas can
harm the tissues of plants and animals.
C. Particulate Pollution
1. is a mixture of dust, acids, and other chemicals that
can be harmful to human health.
2. The particles are usually the most harmful because they
can be inhaled and can cause asthma and bronchitis and lead to heart attacks.
66 Earth’s Atmosphere
Name Date Class
Lesson Outline continued
D. Movement of Air Pollution
1. can carry air pollution from one place to another.
2. A(n) can trap pollution in a valley for a number of
days.
E. Maintaining Healthful Air Quality
1. The of 1970 allows the U.S. government to set limits
on levels of harmful pollutants, including carbon monoxide, lead, nitrogen oxides,
ozone, particulate matter, and sulfur dioxide.
2. Officials air pollution levels in all major U.S. cities.
When pollution levels become high, they issue and
recommend that people limit certain activities, such as exercising outside and
driving.
F. Air Quality Trends
1. Because of the Clean Air Act, levels of most air pollutants have
greatly in the past four decades.
2. The level of ground-level ozone has increased mainly because of the increased
number of .
3. air pollution can be 50 times stronger than
air pollution.
a. Sources of include tobacco smoke, cleaning products,
and some carpets and upholstery.
b. The gas , which escapes from some soil, enters
buildings through cracks in foundations.
Earth’s Atmosphere 67
Name Date Class
LESSON 4: 15 minutes
Can breathing in fresh air be harmful to your health?
Is your health going to be affected if you play tennis for a couple of hours, bike with your
friends, or even just lie on the beach? Even if you have no health problems related to your
respiratory system, you still need to be aware of the quality of air in your area of activity for
the day.
|Air Quality Index |Levels of Health Concern |
|(AQI Values) | |
|0 to 50 |Good |
|51 to 100 |Moderate |
|101 to 150 |Unhealthful for Sensitive Groups |
|151 to 200 |Unhealthful |
|201 to 300 |Very Unhealthful |
|301 to 500 |Hazardous |
Analyze and Conclude
1. Which values on the AQI indicate that the air quality is good?
2. At what value is the air quality unhealthful for anyone who might have allergies and
respiratory disorders?
3. Which values would be considered as warnings of emergency conditions?
4. Key Concept The quality of air in different areas changes throughout the day.
Explain how you can use the AQI to help you know when you should limit your
outdoor activity.
68 Earth’s Atmosphere
Name Date Class
LESSON 4
Air Quality
Directions: Circle the term in parentheses that correctly completes each sentence.
1. Air pollution can cause several (neurological/respiratory) diseases.
2. All the cars in a city are an example of a (point/nonpoint) source of pollution.
3. When chemicals in the air interact with sunlight, (smog/acid rain) can develop.
4. The compound (sulfur dioxide/carbon dioxide) is a corrosive pollutant.
5. Natural sources of methane include (forest vegetation/marsh bacteria).
6. A cubic centimeter of air typically contains more than one (thousand/million) solid or
liquid particles.
7. The (smallest/largest) particles we breathe in are the most hazardous to our health.
8. A temperature (conversion/inversion) can lead to a buildup of air pollution.
9. The (Clean Air/Air Quality) Act of 1970 has led to improved air quality in the United
States.
10. On the Air Quality Index, the most dangerous air conditions are symbolized by the
color (red/maroon).
Earth’s Atmosphere 69
Name Date Class
LESSON 4
Air Quality
Directions: Answer each question or respond to each statement on the lines provided.
1. Explain what point and nonpoint sources of air pollution are. Give an example
of each.
2. Why is ozone considered to be a beneficial gas in the stratosphere but a pollutant at
ground level?
3. How is smog produced?
4. Why do cities located in valleys often have serious air pollution problems?
5. What are the six levels of air quality on the Air Quality Index, and which colors
represent them? (It is not necessary to give the numerical values.)
70 Earth’s Atmosphere
Name Date Class
LESSON 4
Use Graphs
The graph below shows the percent change in four different pollution factors from 1970 to
2006. Each pollution factor is given the value of 0 percent in 1970.
What was the percent change in vehicle miles traveled from 1970 to 2001?
|Step 1 Find the needed information on |Step 2 Subtract to solve the problem. |
|the graph. First find the year on |150% - 0% = 150% |
|the bottom, horizontal axis. Then |The vehicle miles traveled increased |
|find the corresponding percent on |150% from 1970 to 2001. |
|the left, vertical axis. | |
|1970 = 0% | |
|2001 = 150% | |
|Practice | |
|1. What was the percent change in |3. What was the approximate percent |
|vehicle miles traveled between 1990 |change in air pollution between 1995 |
|and 2001? |and 2006? |
| | |
| | |
| | |
|2. What was the approximate percent |4. What was the percent change in |
|change in air pollution between 1970 |energy consumption between 1970 |
|and 1995? |and 2006? |
Earth’s Atmosphere 71
Name Date Class
LESSON 4
Air Quality
Key Concept How do humans impact air quality?
Directions: On the line before each air pollution source listed below, write P if it is a point source or N if it is a
nonpoint source.
1. large city
2. coal-burning power plant
3. erupting volcano
4. swamp microorganisms
5. old factory
6. busy highway
7. airplanes
8. open furnace where trash is burned
Directions: Answer each question on the lines provided.
9. What type of precipitation is often formed when chemicals in the atmosphere combine
with water vapor?
10. What are three lung diseases that can be caused by air pollution?
Earth’s Atmosphere 73
Name Date Class
LESSON 4
Air Quality
Key Concept How do humans impact air quality?
Directions: On each line, write the term from the word bank that correctly completes each sentence. Each term is
used only once.
|chemistry |methane |nitrogen dioxide |ozone |
|sulfur dioxide |sunlight |temperature |wind |
1. Marshes and volcanoes are natural sources of .
2. The patterns in an area can influence the buildup of
pollutants in the air.
3. A major contributor to smog is from gasoline exhaust.
4. Acid precipitation affects the of rivers and lakes.
5. Although is beneficial in the upper atmosphere, it is a
pollutant at ground level.
6. Bacteria in swamps release into the air.
7. Smog forms when chemicals in the air interact with .
8. The of different air layers can determine how polluted the
lower atmosphere becomes.
Earth’s Atmosphere 75
Name Date Class
LESSON 4
Air Quality
Key Concept Why do humans monitor air quality standards?
Directions: On the line before each statement, write T if the statement is true or F if the statement is false.
1. The Clean Air Act became law in 1970.
2. Levels of particulate matter in the air have decreased in U.S. cities during the
past 35 years.
3. A problem that persists is unhealthful levels of ground-level ozone in many
cities.
4. Many lakes and rivers are still being harmed by smog.
5. Carpets and cleaning products are examples of indoor air pollutants.
6. The color maroon on the Air Quality Index means that air conditions are
moderate.
7. The color orange on the Air Quality Index means that air conditions are
unhealthful for sensitive groups.
8. When air pollution levels are high, authorities might advise people to limit
outdoor activities.
76 Earth’s Atmosphere
Name Date Class
40 minutes
Radiant Energy Absorption
The Sun is the source of all energy for Earth. Energy from the Sun is absorbed or reflected
from different surfaces as it radiates toward Earth. Light, bright surfaces reflect energy, and
dark surfaces absorb energy. Land and sea surfaces absorb radiant energy from the Sun, and
air that is in contact with these warm surfaces is warmed through conduction.
Ask a Question
Which surfaces on Earth absorb the most energy from the Sun?
Materials
|thermometer |potting soil |
|lamp |500-mL beaker |
|spoon |paper towels |
|sand |clay |
|stopwatch | |
Safety
Make Observations
1. Read and complete a lab safety form.
2. Use the data table below to record your observations of energy transfer.
|Type of Surface |Temperature Before |Temperature After |
| |Heating |Heating |
|Sand | | |
|Clay | | |
|Topsoil | | |
3. Half-fill a 500-mL beaker with sand. Place a thermometer in the sand and carefully
add enough sand to cover the thermometer bulb––about 2 cm deep. Keep the bulb
under the sand for 1 minute. Record the temperature in the data table.
4. Place the beaker under the light source. Record the temperature after 10 minutes.
5. Repeat steps 3 and 4 using soil and water.
Earth’s Atmosphere 81
Name Date Class
Form a Hypothesis
6. Use the data in your table to form a hypothesis about which surfaces on Earth, such
as forests, wheat fields, lakes, snowy mountaintops, and deserts, will absorb the most
energy from the Sun.
Test Your Hypothesis
7. Decide which materials could best act like the surfaces on Earth from your hypothesis.
8. Repeat the experiment with materials approved by the teacher to test your hypothesis.
9. Examine your data. Do they support your hypothesis? Why or why not?
Analyze and Conclude
10. Infer which types of areas on Earth absorb the most energy from the Sun. Use the
areas listed in step 5 as examples.
11. Think Critically How might changing the surface of Earth, such as paving large areas,
cutting down forests, or draining lakes, affect how the Sun’s energy is absorbed or
reflected?
How might changing the surface of Earth affect
conduction and convection in the atmosphere?
82 Earth’s Atmosphere
Name Date Class
12. The Big Idea How does the absorption and reflection of thermal energy from
the Sun on Earth’s surface relate to keeping conditions in the atmosphere suitable
for life?
Communicate Your Results
Display data from your initial observations to compare your findings with your classmates’
findings. Explain your hypothesis, experiment results, and conclusions to the class.
Lab Tips
• If possible, use leaves, straw, shaved ice, and other natural materials to test your
hypothesis.
Earth’s Atmosphere 8
-----------------------
Launch Lab
|Substances |pH |
|Hydrochloric acid |0.0 |
|Lemon juice |2.3 |
|Vinegar |2.9 |
|Tomato juice |4.1 |
|Coffee (black) |5.0 |
|Acid rain |5.6 |
|Rainwater |6.5 |
|Milk |6.6 |
|Distilled water |7.0 |
|Blood |7.4 |
|Baking soda solution |8.4 |
|Toothpaste |9.9 |
|Household ammonia |11.9 |
|Sodium hydroxide |14.0 |
Content Vocabulary
Lesson Outline
MiniLab
Content Practice A
Content Practice B
Math Skills
Key Concept Builder
Key Concept Builder
Key Concept Builder
Lab A
Lab A continued
Lab A continued
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