Page 498 - Environment: The Science Behind the Stories

Identify major pollutants, outline the scope of outdoor dangers to life because they allow more ultraviolet radia-
air pollution, and assess solutions tion to reach Earth’s surface. (pp. 486–487)

• Natural sources such as fires, volcanoes, and windblown • Ozone depletion is most severe over Antarctica, where an
dust pollute the atmosphere. Human activity can worsen “ozone hole” appears each spring. (p. 487)
some of these phenomena. (pp. 474–475)
• The Montreal Protocol and its follow-up agreements have
• The pollutants we emit include primary and secondary pol- proven remarkably successful in reducing emissions of
lutants from point and non-point sources. (p. 475) ozone-depleting substances. (p. 490)

• To safeguard public health under the Clean Air Act, the • The long residence time of CFCs in the atmosphere
U.S. EPA and state governments monitor emissions of six accounts for a time lag between the protocol and full
major pollutants: carbon monoxide, sulfur dioxide, nitro- restoration of stratospheric ozone. (p. 490)
gen oxides, volatile organic compounds, particulate matter,
and lead. (pp. 476–477) Define acid deposition, illustrate its consequences,
• Agencies also monitor ambient concentrations of the six and explain how we are addressing it
criteria pollutants: carbon monoxide, sulfur dioxide, nitro- • Acid deposition results when pollutants such as SO and
2
gen dioxide, tropospheric ozone, particulate matter, and NO react in the atmosphere to produce strong acids that are
lead. (p. 478) deposited on Earth’s surface. (p. 491)
• Thanks to public policy and to pollution-control tech- • Acid deposition may be wet (e.g., “acid rain”) or dry, and
nologies, emissions in the United States have decreased it may occur a long distance from the source of pollution.
substantially since 1970, and ambient air quality has (p. 491)
improved in most respects. (pp. 477–480)
• Acid deposition damages soils, water bodies, plants, ani-
• Emissions of 187 toxic air pollutants are also declining, but mals, ecosystems, and human property and infrastructure.
they still pose health risks. (p. 480) (pp. 491–492)
• The U.S. EPA is taking early steps toward regulating • Regulation, cap-and-trade programs, and technology are
greenhouse gases as pollutants because they drive climate all helping to reduce acid deposition in North America.
change. (pp. 480–481) Industrializing nations will need to tackle the problem as
• Industrializing nations such as China and India are experi- well. (pp. 492–493)
encing some of the world’s worst air pollution today. (pp.
481–482) Characterize the scope of indoor air pollution and
assess solutions
• Industrial smog produced by fossil fuel combustion is still
a problem in urban and industrial areas of many developing • Indoor air pollution causes more deaths and health prob-
nations. (pp. 482–483) lems worldwide than outdoor air pollution. (p. 493)
• Photochemical smog is created by chemical reactions of • Indoor burning of fuelwood is the developing world’s pri-
pollutants in the presence of sunlight. It impairs visibility mary indoor air pollution risk. (pp. 493–494)
and human health in urban areas. (p. 483) • Tobacco smoke and radon are the worst indoor pollutants
• Cities such as Los Angeles and Mexico City are taking in the developed world. (p. 494)
bold steps to address photochemical smog. (pp. 483, 486) • Volatile organic compounds and living organisms can pol- CHAPTER 17 • AT m os PHER i C sC i E n CE , Ai R Qu A li T y, A nd Poll u T i on Con TR ol
lute indoor air. (pp. 494–495)
Explain stratospheric ozone depletion and identify
steps taken to address it • Using low-toxicity materials, keeping spaces clean, moni-
toring air quality, and maximizing ventilation all help to
• CFCs and other persistent human-made compounds destroy enhance indoor air quality. (p. 496)
stratospheric ozone. Thinning ozone concentrations pose

testing your Comprehension

1. What determines the amount of solar radiation that strikes 3. How does solar energy influence weather and climate?
Earth’s surface? What is the role of solar energy in creat- Describe how Hadley, Ferrel, and polar cells help to
ing seasons? determine long-term climatic patterns and the location of
2. Where is the “ozone layer” located? How and why is biomes.
stratospheric ozone beneficial for people, whereas tropo- 497
spheric ozone is harmful?

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