Encyclopedia of Global Resources part 6 pot

second largest energy cost associated with agriculture.
The use of fuel-requiring pumps to irrigate crops is
also a major energy consumer. Additional energy is
used in food processing, distribution, storage, and
cooking after the crop leaves the farm. The energy
used for these activities may be five times as much as
that used to produce the crop.
Current Trends in Agriculture
The development of biofuels, fuels produced from
plants, such as corn and soy ethanol and cellulosic
ethanol (produced from inedible portions of plants),
has been encouraged by the need to find a substitute
for expensive and environmentally harmful fossil fu-
els. However, the fluctuating price of oil has caused
this industry to advance in fits and starts. Critics point
out that biofuels use cropland that otherwise would
be producing food, and the rise of the electric car
could speed the decline in the use of fossil fuels, mak-
ing biofuels obsolete.
The next major development in agriculture will be
the biotechnical revolution, in which scientists will be
able to use molecular biological techniques to pro-
duce exotic new crop varieties. In the future, perhaps
agricultural scientists will be able to use these tech-
niques to develop crop plants that can be produced,
processed, and distributed with less impact on other
resources. Many scientists feel nanotechnology, the
ability to restructure matter at the level of molecules
and atoms, could meet the needfor growth inagricul-
ture through improving the production of both plants
and animals and improving both the safety and qual-

ity of food.A wide range ofdeveloped and developing
countries, from the United Kingdom to Iran to India,
are providing funding to scientific laboratories to de-
velop nanotechnology products. The potential prod-
ucts range from antibacterial agents to technology
that signals when a product is near the end of its shelf
life. There remains concern that including nanopar-
ticles in food may pose a health risk, and consumer
advocates are encouraging more research, consumer
awareness, and governance.
The trend toward globalization in agriculture has
been good for the developed countries, but it poses a
threat to developing nations. For example, countries
in Africa do not benefit from the advances in global
agriculture. Rural dwellers have neither the money
nor the natural resources to take advantage of mod
-
ern agricultural methods. At the same time, the agri
-
cultural practices in the developed world bring with
them many negative consequences for the environ
-
ment. Water pollution from fertilizers and pesticides;
global warming from increasing land under cultiva-
tion and decreasing forests; and decreased diversityof
agricultural productsinspecificregions,whichresults
in increased energy use to get these products to their
global markets. Interest in organic farming, which is
practiced in more than one hundred countries, offers
opportunities for organic farmers from developing

countries. However, if organic farming follows the
pattern of commercial agriculture, withthe growth of
large farms, specialized products, and need for in-
creasing capital, the benefit to the small, local farmer
will disappear andtheenvironmentalimpact will turn
negative.
Commercial Impact of the Agriculture
Industry
Worldwide, some 45 percent of the population makes
a living through agriculture, both subsistence and
commercial. This also includes those people hired by
the agriculture chemical companies, those compa-
nies that produce or sell agriculture implements and
machinery, processing and canning plants, and whole-
sale and retail marketing firms, such as grocery stores.
There are some eight thousand different agricultural
products on the market, and while agriculture is big
business, it amounts to less than 5 percent of the gross
domestic product of all nations. Approximately one-
third of the land worldwide is used for agriculture.
D. R. Gossett
Further Reading
Akinyemi, Okoro M. Agricultural Production: Organic
and Conventional Systems. Enfield, N.H.: Science
Publishers, 2007.
Brody, Aaron L., and John B. Lord, eds. Developing New
Food Products fora Changing Marketplace. 2ded. Boca
Raton, Fla.: CRC Press/Taylor & Francis, 2008.
Field, Thomas G., and Robert E. Taylor. Scientific Farm
Animal Production: An Introduction to Animal Science.

9th ed. Upper Saddle River, N.J.: Prentice Hall,
2008.
Janick, Jules. Horticultural Science. 4th ed. New York:
W. H. Freeman, 1986.
Kipps, M. S. Production of Field Crops: A Textbook of
Agronomy. 6th ed. New York: McGraw-Hill, 1970.
Metcalfe, Darrel S., and Donald M. Elkins. Crop Pro
-
duction: Principles and Practices. 4th ed. New York:
Macmillan, 1980.
20 • Agriculture industry Global Resources
Southgate, Douglas, Douglas H. Graham, and Luther
Tweeten. The World Food Economy. Malden, Mass.:
Blackwell, 2007.
Weis, Tony. The Global Food Economy: The Battle for the
Future of Farming. New York: Zed Books, 2007.
Wojtkowski, Paul A. Agroecological Economics: Sustain-
ability and Biodiversity. Boston: Elsevier/Academic
Press, 2008.
Web Sites
Agriculture and Agri-Food Canada
Agri-Industries
/>afficher.do?id=1166532974345&lang=eng
U.S. Department of Agriculture
Agriculture
/>7_0_1OB?navtype=SU&navid=AGRICULTURE
See also: Agricultural products; Animal breeding;
Animal domestication; Biofuels; Corn; Cotton; Flax;
Forestry; Forests; Genetic prospecting; Global Strat-
egy for Plant Conservation; Green Revolution; Hemp;

Horticulture; Land ethic; Monoculture agriculture;
Plant domestication and breeding; Plant fibers; Rice;
Rubber, natural; Seed Savers Exchange; Slash-and-
burn agriculture; Soil; Svalbard Global Seed Vault;
United Nations Food and Agriculture Organization;
Wheat; Wood and timber.
Agronomy
Categories: Scientific disciplines; environment,
conservation, and resource management
Agronomy comprises a group of applied-science disci-
plines concerned with land and soil management and
crop production. Agronomists’ areas of interest range
from soil chemistry to soil-plant relationships to land
reclamation.
Definition
There are multiple definitions of agronomy, as befits
a discipline with many different facets. The Oxford
Universal Dictionary defines agronomy as “the study
of land management or rural economy”; Merriam-
Webster’s Collegiate Dictionary calls it “a branch of agri
-
culture dealing with field-crop production and soil
management.” The word derives from the ancient
Greek agros (field) and nemein (manage): field man-
agement. Thus the American Society of Agronomy
defines agronomy as “the theory and practice of crop
production and soil management.”
Overview
Agronomy is essentially the discipline or disciplines
that investigate the production of crops supplying

food, forage, and fiber for human and animal use
and that study the stewardship of the soil from which
those crops are grown. Agronomy covers all aspects of
the agricultural environment, from agroclimatology
to soil-plant relationships; crop science; soil science;
weed science; biometry (the statistics of living things);
crop, soil, pasture, and range management; crop, for-
age, and pasture production and utilization; turf-
grass; and agronomic modeling. Within each area are
subdisciplines. For example, within soil science are
traditional disciplines suchas soil fertility, soil chemis-
try, soil physics, soil microbiology, soil taxonomy and
classification, and pedogenesis (the science of how
soils form). Newer disciplines within soil science in-
clude such studies as bioremediation, or the study of
how living organisms can be used to clean up toxic
wastes in the environment, and land reclamation, the
study of how to reconstruct landscapes disturbed by
human activities such as surface mining.
Agronomy treats the agricultural environment as
humankind’s greatest natural resource: It is the source
of our food, the source of our clothing, the source of
our building materials, and the environment that
purifies the air we breathe and the water we drink.
Agronomists, whatever their specific field, utilize the
soil resources and plant resources around them to
benefit society. Crop breeders, for example, use the
genetic diversity of wild varieties of domesticated
plants to obtain the genetic information needed to
breed plants for greater productivity or pest resis-

tance. Soil scientists study landscapes to determine
how best to manage the soil resource by integrating
agricultural practices with the environment in terms
of maintaining soil fertility and in terms of keeping
soil in place so that erosion does not reduce the qual-
ity of the surrounding environment.
Poor field management leads to reduced produc-
tivity and reduced environmental quality. Historical
examples abound,ranging from the1930’s DustBowl
in theUnited States to the deforestation onthe island
Global Resources Agronomy • 21
of Madagascar in the late twentieth century. It is the
role of agronomy to manage soil and crop resources
as effectively as possible so that the twin goals of pro-
ductivity and environmental quality are preserved.
Mark S. Coyne
See also: Dust Bowl; Erosion and erosion control;
Farmland; Fertilizers; Monoculture agriculture;
Rangeland; Slash-and-burn agriculture; Soil; Soil test-
ing and analysis; Wheat.
Air pollution and air pollution
control
Category: Pollution and waste disposal
An air pollutant is any substance added to the atmo-
sphere by human activities that affects humans, ani-
mals, or the environment adversely. Many pollutants
are toxic, while seemingly benign emissions such as
carbon dioxide, a major contributor to global warm-
ing, and chlorofluorocarbons, which decimate the
stratospheric ozone layer, are dangerous inless obvious

ways. Significant worldwide resources have been com-
mitted to reducing all such hazardous emissions.
Background
Air pollution, occurring in gaseous, particulate, or
aerosol form, has been problematic since humans
began living in large cities and burning carbon-based
fuels. The first known air pollution ordinance was
passed in London in 1273, in an attempt to alleviate
the soot-blackened skies from excessive combustion
of wood. From the mid-eighteenth century through
the mid-twentieth century, the increasingly heavy use
of coal for heat, electricity, and transportation re-
sulted in filthy air and an escalation of respiratory
diseases. In the latter half of the twentieth century,
governments began attacking the problem with legis-
lation to control noxious emissions at their source.
Earth’s atmosphere consists primarily of nitrogen,
oxygen, water vapor,andtraceamountsofmanyother
substances. Emissions from human activities can alter
the concentrations ofthese substances or release nox-
ious chemicals with serious implications—including
smog, acid rain, the greenhouse effect, and holes
in the ozone layer—for both human and planetary
health.
The major air pollutants are carbon oxides, sulfur
oxides, nitrogen oxides, hydrocarbons, and particu-
late matter. Each year the United States adds more
than 5.5 billion metric tons of carbon dioxide (CO
2
)

to the air; China adds approximately 6 billion metric
tons. Worldwide, the amount of CO
2
inserted into the
atmosphere exceeds 28 billion metric tons annually,
contributed in roughly equal proportions by fossil-
fuel electric power plants, industry, transportation,
and homes and businesses.
Air Pollutants
CO
2
results whenever a carbon-containingfuel—such
as coal, oil, or gasoline—is burned. When combustion
is incomplete carbon monoxide (CO) is also pro-
duced. Although CO
2
is a relatively benign compound,
the vast amount of fossil fuels (coal, oil, and natural
gas) burned since the Industrial Revolution has in-
creased the atmospheric amount by about 40 percent
and continues to increase at an escalating rate. Car-
bon dioxide molecules, while transparent in visible
light from the Sun, reflect infrared radiation emitted
by Earth and reradiate it as heat. Eventually, this will
likely raise Earth’s average temperature in proportion
to the amount of atmospheric CO
2
. This “greenhouse
effect” poses a long-term risk because a warming
trend could increase sea levels, change rainfall pat-

terns, disrupt grain belts, cause storms of greater in-
tensity, and shift climate zones. Carbon monoxide is
a toxic compound that causes death by suffocation by
replacing oxygen in the bloodstream, thus depriving
cells of their necessary oxygen.
Sulfur oxides are created wheneverfossilfuels,par-
ticularly coal containing sulfur, are burned. Inhaling
even relatively small concentrationsof these gases can
damage the upper respiratory tract and lung tissue.
Another problem isthatthey react with watervaporin
the atmosphere to produce sulfuric acid, a major
component in acid rain.
Nitrogen oxides are synthesized whenever air is
rapidly heated under pressure, followed by quick
cooling, such as occurs in internal combustion en-
gines and thermoelectric power plants. These com-
pounds play a major role in the formation ofacidrain,
photochemical smog, and ozone (O
3
), a potent reac-
tive compound that attacks the lungs. Combustion-
caused ozone is dangerous to living organisms near
Earth’s surface, but in the stratosphere itoccurs natu
-
rally. This “ozone layer” prevents most of the Sun’s ul
-
traviolet light from reaching Earth’s surface. There
-
22 • Air pollution and air pollution control Global Resources
fore, it can cause skin cancer in humans as well as

affect plants and wildlife adversely.
Particulates are minuscule solid or liquid particles
suspended in the air. They occur from combustion,
dry grinding processes, and spraying. The human re-
spiratory system has evolved a mechanism to prevent
certain sizes of particulates from reaching the lungs,
but there is no protection againstthesmallerparticles
of coal dust and the larger particulates in tobacco
smoke. Coal dust settling in the lungs leads to black
lung disease, while the particulates from tobacco
smoke are a leading cause of lung cancer.
The United States emits millions of metric tons of
suspended particulate matter each year, chiefly from
fossil-fuel electric power plants and industrial smelt-
ing plants. Even particulates that do not reach the
lower regions of the respiratory tract can affect breath-
ing, cause emphysema, aggravate an existing cardio-
vascular disorder, or damage the immune system.
Smog
The word “smog” is a meldingof “smoke” and“fog” to
describe fog polluted by smoke. When a local atmo-
sphere becomes stagnant, smog pollution levels can
create “killer fogs.” Three times in recent history
these killer fogs have caused statistically significant in-
creases in the death rate, particularly among those
with respiratory problems. The first instance oc
-
curred in 1948 in Donora, Pennsylvania, when a stag-
nated fog became progressively more contaminated
with the smoky effluents from local steel mills. The

second case occurred in 1952 in London when a stag-
nant fog mixed with the smoke from thousands of
coal-burning homes caused many with respiratory ail-
ments to die. Finally, during Thanksgiving of 1966,
New York City experienced an increased death rate
because of choking smog.
A second, completely different type of smog is
“photochemical smog,” a noxious mixture of reactive
chemicals created when sunlight catalyzes reactions
of residual hydrocarbons and nitrogen oxides from
automotive exhaust. The first occurrence of such was
in the late 1940’s in Los Angeles, where the abundant
sunlight and the dramatic increase ofvehicular traffic
created ideal conditions for photochemical smog.
This smog contains, among other things, powerful
eye irritants, noisome odors, and dangerous reactive
compounds. Although first observed in Los Angeles,
photochemical smog later became prevalent in most
other large cities.
Chlorofluorocarbons
When first synthesized in the 1930’s, chlorofluoro-
carbon (CFC) was hailed as an ideal refrigerant
Global Resources Air pollution and air pollution control • 23
Data from the U.S. Environmental Protection Agency,Source: National Emissions Inventory (NEI) Air Pollution Emissions Trend Data,
1970-2002.
119.5
36.9
14.9
4.8
0.2

Millions of People
12010080604020
Lead
Ozone
Particulate Matter
(2.5-micron-diameter)
Particulate Matter
(10-micron-diameter)
Sulfur Dioxide
NAAQS (National Ambient Air Quality Standards).Note:
People Living in Countries with Pollution Levels Higher than U.S. NAAQS, 2008
(Freon) because it was nontoxic, noncorrosive, non
-
flammable, and inexpensive to produce. Later, pres-
surized CFCs were used as aerosol propellants and
as the working fluid for air conditioners and refrig-
erators. By 1970 scientists realized that the huge quan-
tities of CFCs released into the atmosphere from
aerosol cans and discarded refrigerant units were
migrating to the stratosphere, where they were de-
composed by highly energetic ultraviolet radiation
from the Sun, releasing large quantities of ozone-
destroying chlorine. The reduction ofozonewasmost
pronounced over Antarctica, where an “ozone hole,”
first detected in the early 1970’s, was increasing in
size annually. In1978, pressured by environmentalists
and consumerboycotts, the U.S. government banned
aerosol cans and refrigeration units utilizingCFCpro-
pellant, forcing the chemical industry to develop al-
ternatives. By 1987 the depletion of the ozone layer

had become so problematic that most industrial na-
tions met in Montreal to ratify an international treaty
calling for immediate reductions in all CFC use with a
complete phase-out by the year 2000. By 2001 the
Montreal Protocol had limited the damage to the
ozone layer to about 10 percent of what it would have
been had the agreement not been ratified.
Air Pollution Control in the United States
In the United States, the first attempts to control the
smog or black smoke prevalent in industrial cities
were the Clean Air Act of 1963 and the Motor Vehicle
Pollution Act of 1965. The 1963 act was too weak to be
effective; in 1967, the stronger Air Quality Act was en-
acted. The Clean Air Act Amendments of 1970 man-
dated national air quality standards set by the Envi-
ronmental Protection Agency (EPA) to be met by
1975. Standards for six major air pollutants (sulfur
oxides, nitrogen oxides, particulates, ozone, carbon
monoxide, and lead)were legislated. When thepollu-
tion concentration exceeded these limits, control de-
vices were obligatory, regardless of the cost.
Although most formsof air pollution were reduced
after enactment of the Clean Air Act Amendments,
mounting public concern over the continuing deteri-
oration ofair quality inmajor cities resulted in several
important revisions in 1990. New legislation man-
dated that coal-burning power plants reduce sulfur
oxide emissions by 9 million metric tonsperyearfrom
1980 levels by the year 2000. The revisions also re-
quired that industry reduce several hundred carcino-

genic airborne substances by up to 90 percent by the
year 2000. Because of its smogproblem, California set
even more stringent standards by legislating that 2
percent of all new vehicles must emit zero emissions
by 1998, a rate that was to increase to 10 percent by
2003. In October, 2006, the EPA’s scientific advisers
recommended that the allowable levels of surface
ozone be substantially reduced, but industrial lobby-
ing and the conservative political climate prevented
any substantial change.
During the decades following the Clean Air Act
Amendments, particulate emissions decreased by 80
percent, carbon monoxide by 55 percent, hydrocar-
bon emissions by 40 percent, sulfur oxides by 27 per-
cent, and atmospheric lead by 98 percent. The partic-
ulate emission reduction is attributed to control
equipment installed on utility plant and industrial
smokestacks, a decreased use of coal, and lessburning
of solid wastes. Carbon monoxide and hydrocarbon
emissions have decreased, despiteanincrease in auto-
motive traffic, because of federal automotive emis-
sion standards. The drop in sulfur oxides is directly
attributable to a switch to low-sulfur coal and the re-
moval of sulfur from the discharged gases at electric
power plants. The drastic drop of lead compounds in
the atmosphere resulted from the switch to unleaded
gasoline during the 1970’s.
During the first decade of the twenty-first century,
concern aboutglobal warming causedbyCO
2

created
a consensus that drastic action was needed to reduce
this threat. Early in 2009, the EPA declared CO
2
an air
24 • Air pollution and air pollution control Global Resources
Percentage Change in U.S. Emissions
(millions of tons per year)
1980 vs. 2008
Carbon monoxide −56
Lead −99
Nitrogen oxides −40
Volatile organic compounds −47
Direct particulate matter
(10-micron-diameter)
−68
Direct particulate matter
(2.5-micron-diameter)
—
Sulfur dioxide −56
Source: Data from U.S. Environmental Protection Agency,
Air Quality Trends, 2009.
pollutant, thus empowering the Clean
Air Act to establish national emission
standards for new automobiles and new
coal-fired electric power plants, the two
largest contributors to global warming
emissions.
Global Air Quality Control
Air pollution, an ongoingproblem in in-

dustrialized nations, has also become
problematic in virtually all undeveloped
countries undergoing rapid industrial-
ization. The countries of the European
Union have taken collective action be-
cause pollution generated in one coun-
try affects air quality in neighboring
countries. Because road transportation
is Europe’slargestairpolluter,beginning
in the 1970’s motor vehicles manufac-
tured on the Continent have had re-
quired exhaust-emission controls. Fossil-
fuel emissions from power plants and
factories are also stringently regulated.
In the United Kingdom, national air quality objectives
were instituted in 2000 in association with an air qual-
ity network to monitor levels of major pollutants invari-
ous locations andadaily warning systemto indicate po-
tentiallydangerousairpollutionlevels.Inthesummer
of 2006, a directive on emission ceilings for cleaner air
in Europe was passed by the European Parliament.
The environmental crisis in the former Soviet re-
publics of Eastern Europe is a direct result of the poli-
cies pursued under the communist regime, when
rapid industrialization ignored local conditions. Air
pollution controls were deemedunnecessary because
the biosphere was assumed to be self-purifying. With
the advent of glasnost, a state committee on environ-
mental protection was instituted in 1988; this became
a state ministry in 1991 but was abolished nine years

later. No significant change inecologicalconcerns oc-
curred after the fall of the communist regime and the
transition to capitalism.Becauseagencies responsible
for environmental matters are either nonexistent or
severely underfunded, internationally funded pollu-
tion abatement projects are abandoned when the
funds expire.
The country with the greatest number of prema-
ture deaths because of air pollution is India, where
rapid industrialization and urbanization combined
with unregulated vehicular emissions and uncon
-
trolled industrial effluents have exacerbated a preex-
isting problem. Legislation to alleviate the crisis in
cities such as New Delhi, one of the top-ten most pol-
luted cities in the world, has been extremely difficult
to implement. Auto emissions account for approxi-
mately 70 percent of urban air pollution, and regula-
tions required all public transportation vehicles in
New Delhi to switch to compressed natural gas en-
gines by April 1, 2001. However, the statute had to be
rescinded when it removed about fifteen thousand
taxis and ten thousand buses from service, creating
commuter chaos and public riots. India’s high airpol-
lution has not happened because of a lack of legisla-
tion but becauseof insufficient enforcement at thelo-
cal level.
China’s growing economy has removed millions of
people from poverty, to the detriment of the environ-
ment. The increase of urban automotive traffic, the

dependence on coal, and a weak environmental pro-
tection system have left China with sixteen of the
world’s twenty most polluted cities. Both urban and
rural dwellers suffer from air pollution, which annu-
ally causes approximately 400,000 premature deaths
and 75 million asthma attacks. In 2005, to help allevi-
ate the problem, the government proposed that strict
fuel efficiency standards and emission controls be
required on all vehicles. China’s excessive air pollu
-
Global Resources Air pollution and air pollution control • 25
In Bangladesh, workers in a brick field stand adjacent to a chimney emitting black
smoke. (AP/Wide World Photos)
tion is not contained within its borders. Unregulated
airborne effluents from the numerous coal-burning
plants reach Japan and become a major contributor
to acid rain. In addition, sulfate-encrusted dust, car-
bon particulates, andnitrates cross the Pacific Ocean,
where they are responsible foralmost one-third ofthe
polluted air over Los Angeles and San Francisco.
Arguably, Japan is the Asian country that has taken
air pollution abatement and control most seriously.
Laws regulating the emission of sulfur dioxide and ni-
trogen oxides are among the strictest in theworld,but
polluted air from China keeps the rain acidic. The
huge increase in automotivetraffic in recent decades is
a major contributor to urban air pollution as well as se-
vere congestion. Several stringent laws regulate auto-
motive emissions in an attempt to control these re-
lated problems. In addition, the Japanese environment

agency promotes low-emission vehicles andcontinues
to strengthen measures to reduce factory emissions.
In June, 2001, the Japanese legislature passed a law
strengthening controls on diesel vehicle emissions; two
years later, diesel-powered commercial vehicles were
banned from Tokyo if these limits were exceeded.
Context
More than three million premature deaths in the
world occur annually because of air pollution, the
greatest number of these occurring in India. In both
developed and developing nations,airpollutionfrom
the escalating number ofvehicles,aswell as consumer
preference for larger, more powerful vehicles, con-
tinues as a major challenge despite gains since the
1980’s. Controlling air pollution is not inexpensive.
Pollution control devices increase costs to factories
and to automobiles, costs that are passed to the con-
sumer. Unless a radical change away from conspicu-
ous consumption and the overreliance on fossil fuels
occurs, air quality will not improve substantially.
The issue of whether global warming is caused by
humans may not be completely resolved, but strong
measures to control carbon dioxide as wellas noxious
gaseous and particulate air pollutants began during
the last decades of the twentieth century. Because the
preponderance of scientific evidence suggests that
global warming is due to humanity’s excessive use
of fossil fuels, it would seem prudent to curtail the
disproportionate dependence on nonrenewable re-
sources. When it was discovered that the ozone layer

was being depleted by CFCs, the Montreal Protocol
was ratified by most industrial nations. This precedent
indicates that strong, effective action and interna
-
tional cooperation are possible when the threat tothe
environment are grave enough.
George R. Plitnik
Further Reading
Ayres, Jon, Robert Maynard, and Roy Richards, eds.
Air Pollution and Health. London: Imperial College
Press, 2006.
Calhoun, Yael, ed. Air Quality. Philadelphia: Chelsea
House, 2005.
Gribbin, John. Hothouse Earth: The Greenhouse Effect
and GAIA. New York: Grove Weidenfeld, 1990.
Jacobson, Mark Z. Atmospheric Pollution: History, Sci-
ence, and Regulation. New York: Cambridge Univer-
sity Press, 2002.
Metcalfe, Sarah, and Dick Derwent. Atmospheric Pollu-
tion and Environmental Change. London: Hodder
Arnold, 2005.
Miller, G. Tyler, Jr. Living in the Environment: Principles,
Connections, and Solutions. 15th ed. Pacific Grove,
Calif.: Brooks/Cole, 2007.
Seinfeld, John H., and Spyros N. Pandis. Atmospheric
Chemistry and Physics: From Air Pollution to Climate
Change. New York: John Wiley & Sons, 2006.
Somerville, Richard C. J. The Forgiving Air:Understand-
ing Environmental Change. 2d ed. Boston: American
Meteorological Society, 2008.

Vallero, Daniel. Fundamentals of Air Pollution. 4th ed.
Burlington, Mass.: Academic Press, 2008.
Web Sites
Environment Canada
Clean Air Online
/>WS8C3F7D55-1_En.htm
U.S. Environmental Protection Agency
Clean Air Act
/>U.S. Environmental Protection Agency
Air Pollution Effects
/>airairpollutioneffects.html
See also: Acid precipitation; Atmosphere; Carbon;
Clean Air Act; Electrical power; Environmental Pro-
tection Agency; Greenhouse gases and global climate
change; Internal combustion engine; Ozone layer
and ozone hole debate.
26 • Air pollution and air pollution control Global Resources
Alaska pipeline
Categories: Historical events and movements;
obtaining and using resources
Date: Congress authorized construction in
November, 1973; construction began April, 1974;
pipeline completed in 1977
The planto construct a trans-Alaskan oil pipelinenet-
work generated considerable controversy. After comple-
tion, the pipeline, a triumph of engineering, helped
lower U.S. dependency on imported oil during the
1980’s.
Background
The Naval Petroleum Reserve was created on the

north slopeofAlaska in 1923, butfor two decades, the
exploratory wells drilled there came up dry. More
-
over, the cost of commercial drilling in Alaska ap-
peared prohibitive. From the 1930’s to the 1950’s, oil
was cheap, and interest in Alaska’s unproven reserves
plummeted.
During the 1960’s, the increasing price of oil and
the possibility of a decline in the security of oil sup-
plied from abroad combined to revive interest in
Alaska’s oil possibilities. The Atlantic Richfield Com-
pany (later ARCO) obtained the majority of the gov-
ernment leases granted for exploratory and develop-
mental activity in Alaska. On December 26, 1967, in
temperatures 30° Celsius belowzero, ARCO struck oil
and discovered the largest oil field ever found in
North America.
Huge technological challenges had to be over-
come, including obtaining the oil in volume in the
subzero temperatures of Alaska’s north slope and
Global Resources Alaska pipeline • 27
This portion of the Alaska pipeline was designed to trace the path of the Denali fault. (USGS)
transporting itsafely to theport of Valdez in the south
of Alaska for shipment by tankers to California. Con-
struction of a mammoth,nearly 1,300-kilometer pipe-
line seemed to be the only way to transport the oil
across the frozen tundra.
The political obstacles to transporting the oil
proved even more challenging. Environmentalists
feared that the pipelinewoulddo irrevocabledamage

to Alaska’s ecological systems. The National Environ-
mental Policy Act (NEPA), which was passed after the
Santa Barbara oil spillof1969, gave environmentalists
the leverage they needed to oppose the pipeline’s
construction. When the Department of the Interior
tried to satisfy the NEPA requirements by filing a
slight eight-page environmental impact statement,
the Friends of the Earth and the Environmental De-
fense Fund obtained a court injunction on April 13,
1970, which halted construction of the pipeline until
a definitive court ruling on compliance with NEPA
could be obtained.
Work on the pipeline was suspended for nearly
four years as proponents and opponents battled in
the bureaucracy andthe courts. Then came the Octo-
ber, 1973, Yom Kippur War, the Arab oil embargo on
Western countries assisting Israel, and the quadru-
pling of the price of imported oil to nearly twelve dol-
lars per barrel. A month later, on November 16, 1973,
Congress relieved the Department of the Interior of
further obligations under NEPA and approved the
construction of a nearly ten-billion-dollar trans-
Alaska pipelinefrom Prudhoe Bay to Valdez. In April,
1974, the monumental task of constructing apipeline
that would notbeenvironmentallydisruptive began.
Impact on Resource Use
The pipelinewas completed in 1977 and within ayear
was carrying one million barrels of oil per day to
Valdez. By the early 1980’s, the amount being trans-
ported had doubled, reducing the U.S. appetite for

imported oil. The opening of the Alaska pipeline
came too late to prevent a second oil crisis in 1979
from driving the price of imported oil to more than
thirty-six dollars per barrel butnot too late to contrib-
ute to the general decline in Western demand for Or-
ganization of Petroleum Exporting Countries (OPEC)
oil during the 1980’s. During that decade OPEC lost
control over the production rates of member states
and was unable to prevent the price of oil from plum
-
meting before restabilizing in the 1990’s at approxi
-
mately twenty dollars per barrel. In 2006, oil prices
spiked again when the Department ofTransportation
insisted the Alaska pipeline be examined after an oil
spill that leaked nearly6,290barrels. Upon inspection
conducted by British Petroleum (BP), the pipeline
was found to have a high level ofcorrosion,forcingBP
to replace nearly 26 kilometers of pipeline and caus-
ing a temporary shutdown of service.
Joseph R. Rudolph, Jr.
See also: Energy economics; Energy politics; Exxon
Valdez oil spill; Oil and natural gas drilling and wells;
Oil and natural gas exploration; Organization of Pe-
troleum Exporting Countries.
Alloys
Categories: Mineral and other nonliving
resources; products from resources
Alloys are solid combinations of metals or of metals
and nonmetallic elementsthathave technologically de-

sirable properties. The discoveries of various alloys have
marked significant turning points in human history.
Background
Alloys are mixtures of metal—such as iron, coal, cop-
per, tin, and lead—with other metals or with nonme-
tallic elements developed to add desirable properties
to those possessed by the metallic elements. These
properties include strength, hardness, resistance to
corrosion, and the ability to withstand high tempera-
tures. The properties of alloys depend not only on
their chemical composition but also on the way they
have been prepared. Steel, a family of alloys based on
the addition of carbon and other elements to iron, is
perhaps the most familiar example in modern tech-
nology, but alloys based on aluminum, cobalt, gold,
nickel, mercury, titanium, and many other elements
are also of great practical importance. In many cases
the role they play in alloy formation is the determin-
ing factor in the importance attached to these ele-
ments as natural resources. The metals used in alloys
must be extracted from theirores, a process that often
leaves environmentally troublesomeby-productssuch
as sulfur oxides. The manufacture of alloys generally
requires sustained high temperatures, creating a de
-
mand for fossil fuels and raising concern about ther
-
mal pollution.
28 • Alloys Global Resources
History

Archaeologists and historians have named the stages
of early civilization after the principal materials used
for tools in each of them. Thus at various times in dif-
ferent parts of the world, civilization progressed from
the Stone Age to a Bronze Age, and then to an Iron
Age. Bronze, a mixture of copper andtin, was the first
alloy to receive extensive use. Bronze artifacts dated as
early as 3500 b.c.e. have been found in both Asia Mi-
nor andChina. The Hittites are believed to have been
the first peoples, in about 1500 b.c.e., to have discov-
ered how to extractmetallic iron from its ores. Thesu-
perior strength of iron led to the replacement of
bronze by iron in armor, weaponry, and knives. The
iron used by early civilizations was undoubtedly an al-
loy, though it was not understood as such. Steel,
formed bythe addition ofcarbon to iron, wasmade in
India by 1000 b.c.e. Brass, a mixture of copper and
zinc, appears to have been known to the Romans.
Modern Alloys
Alloys are generally grouped into ferrous alloys, those
containing iron, and nonferrous alloys. Bronze and
brass remain among the mostcommonnonferrous al-
loys. Bronze is used in numerous industrial applica-
tions and as a durable material for sculptures. Brass is
readily machined and widely used in hardware, elec-
trical fixtures, and decorations. Aluminum, extracted
from bauxite ore by high-temperature electrolysis, is
alloyed with manganese, magnesium, or other ele-
ments to produce a lightweight rigid material.
Ferrous alloys include steels and cast iron. Cast

irons are alloys of iron with 2 to 4 percent carbon and
up to 3 percent silicon. Steels are alloys of iron that
contain a smalleramountof carbon as wellas other el-
ements. The manufacture of steel requires extremely
high temperatures. Numerous forms of steel exist.
Chromium steel has increased hardness and rust re-
sistance. Stainless steel is a special form of chromium
steel with admixtures of manganese, silicon, and
nickel. Molybdenum, titanium, phosphorus, and sele-
nium may also be added. Manganese is added to steel
to increase strength and durability. Tungsten steels
are stronger at high temperatures. Vanadium steel
has greater elasticity and is suited to parts that must
bend and regain their shape.
Alloys of gold and silver are important in coinage
and for decorative purposes. Gold is alloyed with sil
-
ver and copper forjewelry. Sterling silver is an alloy of
silver with copper.
Certain alloys are employed in dentistry and medi
-
cine. Throughout most of the twentieth century den-
tists made liberal use of mercury amalgam, a mold-
able mixture of mercury, silver, and other elements, as
a filling material for dental caries (cavities). Concern
about mercury toxicity led to areduction in use ofthis
material. Orthopedic surgeons frequently use stain-
less steel screws, pins, and rods to hold fractured
bones in place so that they can heal properly. Alloys
also play a role in a variety of orthopedic implants

used to replace badly worn or damaged joints.
Another important group of alloys is thoseusedfor
permanent magnets. These include alnico, a combi-
nation of aluminum, nickel, and cobalt. Other mag-
netic materials include iron-nickel and iron-aluminum
combinations. The rare earth elements also play a
role in some magnetic materials.
Superalloys are materials based on nickel, cobalt,
or an iron-nickel mixture and contain carefully con-
trolled amounts of trace elements designed to exhibit
high strength at temperatures above 1,000° Celsius.
These materials are used in jet engines, in heat ex-
changers, and in chemical production plants.
Impact of Alloys on Natural Resources
The development andrefinement of alloy technology
have had a dual effect on natural resource utilization.
By making a larger variety of consumer goods avail-
able, the development of new alloys has tended to ac-
celerate the use of mineral ores and energy sources.
However, the emergence of alloys that are lighter,
more corrosion resistant, and amenable to recycling,
as well as the replacement of some alloys by polymer-
based materials and other alloys, slowedthe rate ofre-
source use somewhat after its peak in the 1970’s.
Donald R. Franceschetti
Further Reading
Askeland, Donald R., and Pradeep P. Phulé. The Sci-
ence and Engineering of Materials. 5th ed. Toronto:
Nelson, 2006.
Campbell, F. C., ed. Elements of Metallurgy and Engi-

neering Alloys. Materials Park, Ohio: ASM Interna-
tional, 2008.
Kranzberg, Melvin, and Cyril Stanley Smith. “Mate-
rials in History and Society.” In The Materials Revolu-
tion, edited by Tom Forester. Cambridge, Mass.:
MIT Press, 1988.
Plowden, David. Steel. New York: Viking Press, 1981.
Raymond, Robert. Outofthe Fiery Furnace: The Impact of
Global Resources Alloys • 29