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Instructor's Manual and Test Bank to accompany Meteorology Today, 10th Edition
Jonathan D. W. Kahl
University of Wisconsin-Milwaukee
Chapter 18
Air Pollution
Summary
Air pollutants and meteorological phenomena related to air pollution are examined in this chapter.
Many concepts introduced in earlier chapters, such as atmospheric stability and small scale wind
circulation patterns, are relevant to the air pollution problem and are integrated into the discussion. An
early focus section on “Indoor Air Pollution” describes the reasons why indoor air is as much as 100
times more polluted than outdoor air.
The chapter begins with a brief historical review of air pollution. Many students will be
surprised, perhaps, to see that concern over air pollution dates from at least the 13th century. Students
may also be unaware of the very serious air pollution events that occurred earlier in this century in Europe
and the United States. The London smog of 1952, for example, remains the world's worst air pollution
disaster.
Sources and environmental effects of the primary air pollutants, carbon monoxide, sulfur dioxide,
nitrogen oxides, particulate matter and volatile organic compounds are discussed next. The characteristics
of ozone is presented in some detail. A distinction is made between tropospheric and stratospheric ozone,
with the main features, impacts and chemistry details presented for each. A focus section on “The Ozone
Hole” tells a fascinating story of the discovery of this complex phenomenon, and on global effforts to
reduce its harmful effects on the environment.
Returning to ground level, the air quality index (AQI), a quantitative measure of air quality, is
examined. We see that, while air quality has improved following the passage of clean air legislation,
many urban areas still frequently exceed the government-mandated standards.
The roles that weather conditions, including temperature inversions, stability, and local
topography effects play in air pollution are discussed. Focus sections on “Smokestack Plumes” and “Five
Days in Donora - An Air Pollution Episode” describe the relationship between meteorological conditions
and air pollution. The effect of urban heat islands on air pollution is examined. A final focus section on
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“Heat Waves and Air Pollution: A Deadly Team” describes some of the social and economic impacts of
air pollution. The chapter concludes with a discussion of the causes and effects of acid deposition.
Teaching Suggestions
1.
Heat a small piece of coal using a propane torch in class. The burning coal will produce a lot of
sooty black smoke and a pungent, sulfurous odor. Students will get a better appreciation of how
unhealthy conditions must have been during the London smog episodes.
2.
Effective classroom demonstrations of some of the common reactions in air pollution chemistry
have been given by J. L. Hollenberg et al. (ref: "Demonstrating the Chemistry of Air Pollution," J. Chem.
Educ., 64, 893-894, 1987).
3.
Several websites are available which show air quality conditions in different parts of the world.
These include:
U.S.: http://www.airnow.gov/index.cfm?action=airnow.outlook
Mexico City: http://www.calidadaire.df.gob.mx/calidadaire
Canada: http://www.airnow.gov/index.cfm?action=airnow.canada
Europe: http://www.eea.europa.eu/maps/ozone/map
4.
Invite students to share any personal experiences they may have of air pollution episodes or
exposure. Ask them to describe the weather conditions at the time of their experience.
5.
The potential health effects of indoor air pollution are often overlooked. Discuss indoor pollution
with the class. What pollutants are students exposed to? What controls are in place to limit these
exposures?
6.
Have students share their opinions as to the value of visibility as a national resource. Should
controls on visibility-reducing pollutants be aggressively pursued by governmental agencies? Why or
why not?
7.
Examine realtime visibility data using air quality webcams:
http://www.airnow.gov/index.cfm?action=airnow.webcams
8.
Discuss the problem of air pollution in the world’s megacities. A good resource for this is the
article “Megacities and Atmospheric Pollution” by Molina and Molina:
http://wiki.esipfed.org/images/2/2c/MegaCityPollutionMolina.pdf
9.
Discuss the interesting paradox of tropospheric and stratospheric ozone. The same gas is highly
beneficial in one part of the atmosphere, but is considered an undesirable pollutant in another part of the
atmosphere.
10.
When discussing stratospheric ozone, view realtime images of the Antarctic ozone hole:
http://ozonewatch.gsfc.nasa.gov/index.html
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Student Projects
1.
Have students examine daily air quality summaries for their location and report on conditions.
What emissions are of most concern? What are the primary sources of these emissions? How do the
reported values correlate with observed atmospheric conditions, visibility, and synoptic weather
conditions?
2.
Have students investigate and report on measures are being taken locally to reduce air pollution.
This might include carpooling, subsidized bus passes or other use of mass transit, use of oxygenated fuels
during certain times of the year, vehicle emissions inspections, and no-burn nights.
3.
Have students track regional air quality using the EPA AirNow site (http://www.airnow.gov).
Have them describe the local air quality and, if appropriate, any pollution episodes.
4.
Have students use actual Antarctic stratospheric ozone data
(http://ozonewatch.gsfc.nasa.gov/index.html) to explain why ozone concentrations over Antarctica reach
their lowest levels in September and October.
5.
Have students photograph a smokestack plume on different days/times and also record the
corresponding weather observations. Do they find a relationship between plume behavior and weather
conditions similar to that shown in the Focus section on Smokestack Plumes?
Answers to Questions for Review
1.
Natural sources: windblown dust and soot, volcanoes, forest fires. Human-induced sources:
industrial complexes, power plants, homes, office buildings, motor vehicles, ships, aircraft. Secondary
sources: chemical reactions in the atmosphere.
2.
Soot, dust, smoke, pollen, asbestos fibers, arsenic, sulfuric acid droplets, PCBs, oil, pesticides.
3.
Finer particles with diameters smaller than 10 µm are referred to as PM-10. Particles with
diameters smaller than 5 µm are referred to as PM-2.5. PM-2.5 pose the greater health risk because they
can penetrate further into the lung when inhaled, and because they frequently consist of toxic or
carcinogenic compounds.
4.
Washout by rain and snow; incorporation into cloud or fog droplets.
5.
Building materials, pressed wood products, furnishings, and home cleaning products, pesticides,
adhesives, personal care products, heating sources, cigarette smoke, radon, formaldehyde, asbestos.
6.
Inside a home, the radon decays into polonium, a solid substance that attaches itself to dust in the
air. The tiny dust particles can be inhaled deep into the lungs, where they attach to lung tissue. As the
polonium decays, it damages the lung tissue, sometimes producing mutated cells that may develop into
lung cancer.
7.
(a) Incomplete combustion of carbon-containing fuels. It starves blood hemoglobin of oxygen.
(b) Burning of sulfur-containing fossil fuels. When inhaled into the lungs, high concentrations of
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sulfur dioxide aggravate respiratory problems, such as asthma, bronchitis, and emphysema.
(c) Industrial processes and vehicles. Certain VOCs, such as benzene (an industrial solvent) and
benzo-a-pyrene (a product of burning wood, tobacco and barbecuing), are known to be carcinogens—
cancer-causing agents. Although many VOCs are not intrinsically harmful, some will react with nitrogen
oxides in the presence of sunlight to produce secondary pollutants, which are harmful to human health.
(d) High-temperature combustion of fuel from motor vehicles, power plants and waste disposal
systems. High concentrations are believed to contribute to heart and lung problems, as well as lowering
the body’s resistance to respiratory infections.
8.
London smog: mixture of sulfurous smoke and fog. Los Angeles or photochemical smog: forms
when chemical reactions take place in the presence of sunlight.
9.
The main component of photochemical smog is the gas ozone (O3). Ozone is a noxious substance
with an unpleasant odor that irritates eyes and the mucous membranes of the respiratory system,
aggravating chronic diseases, such as asthma and bronchitis. Because sunlight is required to produce
ozone, concentrations of tropospheric ozone are normally higher during the afternoons and during the
summer months, when sunlight is more intense.
10.
(a) In polluted air, sunlight (with wavelengths shorter than about 0.41 µm) dissociates nitrogen
dioxide into nitric oxide and atomic oxygen, which then combines with molecular oxygen to form ozone.
(b) The ozone is then destroyed by combining with nitric oxide, creating nitrogen dioxide. If
sunlight is present, however, the newly formed nitrogen dioxide will break down into nitric oxide and
atomic oxygen. The atomic oxygen then combines with molecular oxygen to form ozone again.
Consequently, large concentrations of ozone can form in polluted air only if some of the nitric oxide
reacts with other gases without removing ozone in the process. Under these conditions, certain
hydrocarbons (emitted by autos and industrial sources) and the hydroxyl radical come into play. The
hydrocarbons (VOCs) also react with oxygen and nitrogen dioxide to produce other undesirable
contaminants, such as PAN (peroxyacetyl nitrate)—a pollutant that irritates eyes and is extremely harmful
to vegetation—and organic compounds.
11.
Ozone (O3) forms naturally in the stratosphere by the combining of atomic oxygen (O) with
molecular oxygen (O2)—in the presence of another molecule. Ozone is broken down into molecular and
atomic oxygen by absorbing ultraviolet radiation and by colliding with other atoms and molecules. Two
natural destructive gases for ozone are nitric oxide (NO) and nitrogen dioxide (NO 2). Human-caused
destructive factors include nitric oxide from high-altitude aircraft and chlorofluorocarbons.
12.
Stratospheric ozone absorbs harmful ultraviolet radiation from the sun, preventing it from causing
cancer in living cells at the earth's surface. Tropospheric ozone, when inhaled, causes respiratory
problems.
13.
Once chlorofluorocarbon molecules reach the middle stratosphere, ultraviolet energy that is
normally absorbed by ozone breaks them up, releasing atomic chlorine in the process. Atomic chlorine
(Cl) combines with ozone, forming chlorine monoxide (ClO)—a new substance—and molecular oxygen
(O2). Almost immediately, the chlorine monoxide combines with free atomic oxygen to produce chlorine
atoms and molecular oxygen. The free chlorine atoms are now ready to combine with and destroy more
ozone molecules. Estimates are that a single chlorine atom removes as many as 100,000 ozone molecules
before it is taken out of action by combining with other substances. If ozone were removed from the
atmosphere, the amount of ultraviolet radiation reaching the earth's surface would reach dangerous levels,
causing widespread cases of skin cancer.
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14.
During September and October (spring in the Southern Hemisphere), a belt of stratospheric winds
called the polar vortex encircles the Antarctic region near 66°S latitude, essentially isolating the cold
Antarctic stratospheric air from the warmer air of the middle latitudes. During the long dark Antarctic
winter, temperatures inside the vortex can drop to -85°C (-121°F). This frigid air allows for the formation
of polar stratospheric clouds. These ice clouds are critical in facilitating chemical interactions among
nitrogen, hydrogen, and chlorine atoms, the end product of which is the destruction of ozone.
15.
Primary ambient air quality standards are set to protect human health, whereas secondary
standards protect human welfare, as measured by the effects of air pollution on visibility, crops, and
buildings. Those areas that do not meet air quality standards are called nonattainment areas.
16.
The wind speed determines how quickly the pollutants mix with the surrounding air and, of
course, how fast they move away from their source.
17.
Atmospheric stability controls the extent to which air mixes and becomes diluted. Stable
conditions are not conducive to mixing and result in high concentrations; unstable conditions dilute the air
and reduce concentrations.
18. Light winds and poor vertical mixing. A region under the domination of a surface high-pressure
area or ridge often experiences clear skies, light winds, and a subsidence inversion. Moreover, where
warm air rides up over cold surface air, such as ahead of an advancing warm front, stable atmospheric
conditions promote the trapping of pollutants near the surface.
19.
An inversion is an example of extreme atmospheric stability, resulting in little or no mixing and
leading to high pollution concentrations.
20.
Shorter smokestacks are likely to have weaker winds, are less likely to rise above an inversion
layer, and are capable of mixing air through a smaller volume of air as compared to taller smokestacks.
21. The atmosphere tends to be most unstable in the afternoon and most stable in the early morning, so
we typically find the greatest mixing depth in the afternoon and the most shallow one (if one exists at all)
in the early morning.
22.
Los Angeles and Denver: the city of Los Angeles is surrounded on three sides by hills and
mountains. Cool marine air from off the ocean moves inland and pushes against the hills, which tend to
block the air’s eastward progress. Unable to rise, the cool air settles in the basin, trapping pollutants from
industry and millions of autos. Baked by sunlight, the pollutants become the infamous photochemical
smog. By the same token, the “mile high” city of Denver, Colorado, sits in a broad shallow basin that
frequently traps both cold air and pollutants. Mountainous terrain: at night, cold air tends to drain
downhill, where it settles into low-lying basins and valleys. The cold air can have several effects: It can
strengthen a preexisting surface inversion, and it can carry pollutants downhill from the surrounding
hillsides.
23.
Many sources of air pollution, a deep high-pressure area that becomes stationary over a region,
light surface winds that are unable to disperse the pollutants, a strong subsidence inversion produced by
the sinking of air aloft, a shallow mixing layer with poor ventilation, a valley where the pollutants can
accumulate, clear skies so that radiational cooling at night will produce a surface inversion, which can
cause an even greater buildup of pollutants near the ground, for photochemical smog, adequate sunlight to
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produce secondary pollutants, such as ozone.
24.
In cities, where less vegetation and exposed soil exists, the majority of the sun’s energy is
absorbed by urban structures and asphalt. Hence, during warm daylight hours, less evaporative cooling in
cities allows surface temperatures to rise higher than in rural areas. At night, the solar energy (stored as
vast quantities of heat in city buildings and roads) is slowly released into the city air. Additional city heat
is given off at night (and during the day) by vehicles and factories, as well as by industrial and domestic
heating and cooling units. The release of heat energy is retarded by the tall vertical city walls that do not
allow infrared radiation to escape as readily as do the relatively level surfaces of the surrounding
countryside. The slow release of heat tends to keep nighttime city temperatures higher than those of the
faster cooling rural areas. Overall, the heat island is strongest at night.
25.
A breeze blowing from the countryside into the city. Thermal gradients caused by the urban heat
island are stronger at night than during the day, so the breeze is stronger at night. It is more easily
developed in the summer, when more solar radiation is available.
26.
Air pollution emitted from industrial areas, especially products of combustion, such as oxides of
sulfur and nitrogen, can be carried many kilometers downwind. Either these particles and gases slowly
settle to the ground in dry form (dry deposition) or they are removed from the air during the formation of
cloud particles and then carried to the ground in rain and snow (wet deposition).
27. High concentrations of acid deposition can damage plants and water resources. Emissions of sulfur
dioxide (SO2) and oxides of nitrogen may settle on the local landscape, where they transform into acids as
they interact with water, especially during the formation of dew or frost. The remaining airborne particles
may transform into tiny dilute drops of sulfuric acid (H2SO4) and nitric acid (HNO3) during a complex
series of chemical reactions involving sunlight, water vapor, and other gases.
Answers to Questions for Thought
1.
(a) No. Ozone is produced by photodissociation of nitrogen dioxide (NO2) and subsequent
combination of atomic and molecular oxygen. Photodissociation of NO2 also produces nitric oxide (NO)
which reacts with and destroys ozone.
(b) Hydrocarbons can react with hydroxyl radicals and then molecular oxygen. The product
reacts with NO to form NO2. Hydrocarbons thus prevent NO from reacting with and destroying ozone.
2.
In the afternoon when the surface air is highest and the atmosphere is most unstable.
3.
Radiation inversions are usually shallow and solar heating causes them to weaken and disappear
by mid-day. Subsidence inversions may persist for several days.
4.
In cities, heat is given off by vehicles and factories as well as by heating and cooling units.
Surface cooling in cities is reduced by the tall walls of buildings. What sunlight does penetrate clouds
and haze in a city produces warming. In rural areas, a substantial portion of the incident sunlight may be
used to evaporate water and doesn't produce warming.
5.
Acid snow can build up over the winter and then be released suddenly into a lake when the snow
melts in the spring. Acid rain would be added to a lake more gradually.
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6.
We wish to reduce high ozone concentrations at the earth’s surface because ozone is a harmful
pollutant that irritates the eyes and the respiratory system, and aggravates chronic respiratory diseases.
Although stratospheric ozone is the same gas, at stratospheric altitudes it doesn’t come into contact with
humans, thus its effects are mainly beneficial (it absorbs UV radiation).
7.
Nighttime inversions would prevent mixing, allowing pollution to become more concentrated.
Also, in the absence of convection forced by incoming solar radiation, the polluted air found near the
ground will not warm and rise to higher altitudes.
8.
The taller smokestack will likely reduce air quality problems in its immediate vicinity. However,
the taller stack will create new air quality problems for areas downwind.
9.
People generally wear clothing when walking in the rain, so most of their skin is protected. Also,
most people bathe frequently, thus washing the acidic rain off their bodies.
Answers to Critical Thinking Questions
Figure 18.11.
Polar sunrise occurs in late March in the northern hemisphere.
Figure 18.17. If the lapse rate below the inversion were to remain the same, surface warming would
raise the base of the inversion, creating a deeper mixed layer and reduced pollution concentrations.
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Multiple Choice Exam Questions
1.
The smoke in London smogs came primarily from
a. exhaust from diesel engines.
b. trash fires.
c. factories in Eastern Europe.
d. coal combustion.
ANSWER: D
2.
Which of the following is not true of fine particulate matter (particles less than one micrometer in
diameter) in the atmosphere?
a. Particles may remain suspended in the atmosphere for several weeks.
b. Particles are not readily removed from the atmosphere by rain and snow.
c. Particles are small enough to penetrate into the lungs.
d. Particles can cause a significant reduction in visibility.
ANSWER: B
3.
Collectively, particles of soot, smoke, dust, and pollen are called
a. hydrocarbons.
b. aerosols.
c. carcinogens.
d. haze.
ANSWER: B
4.
Which of the following statements is not true of carbon monoxide (CO)?
a. It replaces oxygen in the blood's hemoglobin.
b. It is removed slowly from the atmosphere.
c. It is produced by the incomplete combustion of carbon-containing fuels.
d. Roughly half of the CO in the atmosphere is produced by automobiles.
ANSWER: B
5.
Volcanoes are an important natural source of
a. benzene.
b. ozone.
c. sulfur dioxide.
d. carbon monoxide.
e. chlorofluorocarbons.
ANSWER: C
6.
Nitrogen dioxide (NO2) reacts with ____ in the atmosphere to form nitric acid (HNO3).
a. hydrogen
b. water vapor
c. ozone
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d. carbon dioxide
e. sulfur dioxide
ANSWER: B
7.
A primary component of photochemical smog is
a. ozone.
b. carbon monoxide.
c. sulfur dioxide.
d. chlorofluorocarbons.
ANSWER: A
8.
Photochemical smog is also termed
a. London-type smog.
b. subsidence smog.
c. mixing layer smog.
d. sea breeze smog.
e. Los Angeles-type smog.
ANSWER: E
9.
An air quality index value of 35 on a particular day would indicate ____ conditions.
a. good
b. unhealthful
c. extremely hazardous
d. moderately hazardous
ANSWER: A
10.
A looping smoke plume indicates relatively unstable atmospheric conditions.
a. true
b. false
ANSWER: A
11.
The mixing depth is
a. a very stable layer that extends from the surface up to the base of an inversion.
b. an unstable layer that extends from the surface up to the base of an inversion.
c. a very stable layer found upward from an inversion.
d. an unstable layer that extends upward from an inversion.
ANSWER: B
12.
A looping shape exhibited by a smokestack plume is indicative of ____ conditions.
a. inversion
b. stable
c. neutral
d. unstable
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e. both inversion and stable
ANSWER: D
13.
A coning shape exhibited by a smokestack plume is indicative of ____ conditions.
a. inversion
b. stable
c. neutral
d. unstable
e. both inversion and stable
ANSWER: C
14.
A fanning shape exhibited by a smokestack plume is indicative of ____ conditions.
a. inversion
b. stable
c. neutral
d. unstable
e. both inversion and stable
ANSWER: E
15.
A mixing layer is characterized by
a. enhanced vertical air motions.
b. suppressed vertical air motions.
c. strong horizontal winds.
d. high concentrations of pollutants.
ANSWER: A
16.
Which of the following conditions would act to prevent a buildup of pollutants near the surface?
a. light surface winds
b. a strong subsidence inversion
c. a large, slow-moving anticyclone
d. a deep mixing layer
ANSWER: D
17.
Pollution is most severe in urban areas when
a. a cold upper-level low moves into a region.
b. a warm front passes through the area.
c. a large slow-moving anticyclone moves into an area.
d. a storm system begins developing to the west.
e. a cold front passes through the area.
ANSWER: C
18.
Atmospheric stagnation is a condition normally brought on by
a. thunderstorms.
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b.
c.
d.
e.
slow-moving anticyclones.
overcast skies.
tall buildings in a city.
movement of an upper level trough overhead.
ANSWER: B
19.
Which of the following would probably result in polluted conditions over a fairly long duration?
a. a radiation inversion
b. a subsidence inversion
c. persistent winds
d. overcast skies
ANSWER: B
20.
The urban heat island is
a. warmer air temperatures in urban areas compared to surrounding rural areas.
b. a concentration of energy use in an urban area.
c. locating factories in a single location downwind from cities.
d. use of conservation techniques to reduce energy use in cities.
ANSWER: A
21.
Sunshine in a city is typically less intense than in surrounding rural areas because
a. of the higher pollution levels in cities.
b. of the air temperature in cities.
c. tall structures in cities block our view of the horizon.
d. cement and asphalt in cities absorb a larger percentage of the incident sunshine.
ANSWER: A
22.
When contrasted to a rural area, cities usually do not have higher
a. concentrations of pollution.
b. frequency of fog.
c. temperatures.
d. visibilities.
e. frequency of thunderstorms.
ANSWER: D
23.
Studies suggest that downwind of a large industrial area
a. average annual precipitation can increase.
b. higher surface temperatures are observed.
c. breezy conditions are frequently observed.
d. all of the above
ANSWER: A
24.
Which of the following contribute(s) to the formation of an urban heat island?
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a. a large part of the incident sunlight in rural areas is used to evaporate water in vegetation
and the soil
b. heat is released by vehicles in urban areas
c. heat is released slowly in cities at night
d. all of the above
ANSWER: D
25.
On clear, cold winter nights, cities tend to cool ____ than rural areas and have ____ temperatures.
a. more slowly, higher
b. more quickly, higher
c. more slowly, lower
d. more quickly, lower
ANSWER: A
26.
A country breeze would probably be associated with
a. a large high-pressure area that forms over a city.
b. a hot and humid summer day in a large city.
c. a period of heavy rain that falls over a city.
d. a strong urban heat island.
ANSWER: D
27.
A country breeze blows
a. from the city toward the country at night.
b. from the city toward the country during the day.
c. from the country toward the city at night.
d. from the country toward the city during the day.
ANSWER: C
28.
Which is not correct about acid deposition?
a. It is only a problem in New England and Scandinavia.
b. It can damage plants and water resources.
c. It is caused mainly by the release of oxides of sulfur and nitrogen.
d. It can fall to ground in dry or wet forms.
ANSWER: A
29.
The problem of acid rain is probably most severe in which of the following regions?
a. Gulf Coast
b. New England
c. Desert Southwest
d. Pacific Northwest
e. Central Plains
ANSWER: B
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30.
A decline in the health of forests in Germany has been attributed to
a. erosion caused by excessive lumber cutting.
b. acid rain.
c. increased CO2 concentrations and global warming.
d. urbanization.
ANSWER: B
31.
Rain with a pH of 5.6 would be considered
a. acidic.
b. alkaline.
c. neutral.
d. polluted.
e. harmful.
ANSWER: A
32.
Erosion of limestone buildings, fountains, and sculptures is caused largely by
a. acid rain.
b. ozone.
c. vibrations caused by automobile traffic.
d. urban heat island.
ANSWER: A
33.
A greenhouse gas used as a refrigerant, a solvent, and during the manufacture of foam:
a. water vapor (H2O)
b. carbon dioxide (CO2)
c. methane (CH4)
d. polyvinylchloride (PVC)
e. chlorofluorocarbons (CFCs)
ANSWER: E
34.
The ozone hole is found in this atmospheric layer:
a. thermosphere
b. troposphere
c. stratosphere
d. ionosphere
e. mesosphere
ANSWER: C
35.
About 97 percent of all ozone in the atmosphere is found in the
a. stratosphere.
b. troposphere.
c. mesosphere.
d. exosphere.
e. thermosphere.
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ANSWER: A
36.
The so-called "ozone hole" is observed above
a. the continent of North America.
b. the equator.
c. the continent of Australia.
d. the continent of Antarctica.
e. the continent of Asia.
ANSWER: D
37.
The term "ozone hole" refers to a ____ decrease in ozone concentration.
a. permanent
b. seasonal
c. monthly
d. daily
ANSWER: B
38.
If the concentration of ozone were to decrease significantly, which of the following might also
occur?
a. less absorption of ultraviolet radiation in the stratosphere.
b. an increase in the number of cases of skin cancer
c. The stratosphere would cool.
d. More ultraviolet radiation would be absorbed at the earth's surface.
e. all of the above
ANSWER: E
39.
Polar stratospheric clouds are thought to contribute to the problem of
a. global warming.
b. ozone destruction.
c. acid rain.
d. photochemical smog.
e. radio wave interference.
ANSWER: B
40.
When chlorofluorocarbons are subjected to ultraviolet radiation, ____ is released which rapidly
destroys ozone.
a. chlorine
b. nitrogen
c. carbon dioxide
d. carbon
e. water vapor
ANSWER: A
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41.
What gas is produced naturally in the stratosphere and is also a primary component of
photochemical smog in polluted air at the surface?
a. carbon dioxide
b. carbon monoxide
c. ozone
d. nitrogen dioxide
e. hydrocarbons
ANSWER: C
42.
Which of the following is a major way in which chlorofluorocarbons can enter the stratosphere?
a. from the exhaust of high-altitude aircraft
b. in an inversion
c. in building thunderstorms that penetrate into the lower stratosphere
d. from the rupture of radiosonde balloons
ANSWER: C
43.
Once released into the atmosphere, chlorofluorocarbons remain about
a. 10 days.
b. 100 years.
c. 1 year.
d. 1 month.
ANSWER: B
44.
Particulate pollution with diameters less than 2.5 micrometers are particularly dangerous because
a. they can penetrate deep into the lungs.
b. they dissolve easily in water.
c. they are chemically neutralized by dissolved carbon dioxide.
d. they dissolve easily in water and they are chemically neutralized by dissolved carbon
dioxide.
e. none of the above
ANSWER: A
45.
Which of the following are capable of destroying ozone in the stratosphere?
a. oxygen atoms
b. chlorine atoms
c. other ozone molecules
d. all of the above
ANSWER: D
46.
Thunderstorms are most likely to form on a day when smokestack plumes have a
a. fanning shape.
b. looping shape.
c. coning shape.
d. lofting shape.
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ANSWER: B
47.
Suspended particles in the atmosphere can affect climate by
a. reflecting incoming radiation.
b. absorbing outgoing infrared radiation from the earth's surface.
c. all of the above
ANSWER: C
48.
The Los Angeles area has shown a steady decline in the number of unhealthful days due to ozone.
a. true
b. false
ANSWER: A
49.
Indoor air is typically more polluted than outdoor air.
a. true
b. false
ANSWER: A
50.
The country breeze tends to ____ pollutants in the urban air.
a. dilute
b. concentrate
ANSWER: B
Essay Exam Questions
1.
What atmospheric conditions would you expect to find associated with a major air pollution
episode?
2.
What stability condition is most favorable for improving urban air quality? What time of day or
night does this stability condition typically occur?
3.
Explain why locating industrial facilities on the perimeter of a city might not always prevent air
pollution in the city.
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4.
What is the urban heat island effect?
conditions nearby?
How could an urban heat island affect atmospheric
5.
How can topography contribute to pollution in a city or region?
6.
Would you expect to find the same environmental conditions upwind and downwind of a large
city? Explain.
7.
What causes acid rain? What are some of the environmental concerns associated with acid rain?
Are problems with acid rain confined to a small area or do they extend over a large region?
8.
Describe some of the measures that are being taken to reduce the problem of acid precipitation.
9.
How does Los Angeles-type smog differ from London-type smog?
10.
List some of the ways that pollutants are removed from the atmosphere. Does this occur quickly
or slowly?
11.
Describe some of the ways an industrial facility that is constructed in or near a large urban area
could attempt to reduce emissions of air pollutants.
12.
Describe how the use of a tall smoke stack might improve air quality in the vicinity of a large
industrial facility.
13.
Would you expect the concentrations of air pollutants to vary significantly during the day in the
city where you live? If so, when would you expect to find the highest concentrations of
pollutants?
14.
Explain how ozone might be thought to have both a beneficial and a detrimental role in the earth's
atmosphere.
15.
Why doesn’t an acidified lake look polluted?
16.
Would highly polluted cities tend to have more clouds than less-polluted cities? Explain your
answer.