other photochemical oxidants, different types of particulates, lead and other
heavy metals, and various kinds of volatile organic compounds (VOCs). The
major source of air pollution is the combustion of fossil fuels for electricity and
transportation, various industrial processes, heating, and cooking. According
to the North American Commission for Environmental Cooperation (CEC),
one-quarter of the industrial pollution released into the North American
environment in 1998 came from U.S. electric power plants. This is closely
followed by pollution from the primary metals sector, the chemical industry,
and the hazardous waste management sectors.
7
2.1.3.2 Air Pollution and Developing Economies
While problems associated with air pollution remain of global concern,
encouraging results were shown for its control in the U.S. and other
industrialized countries. For example, according to a recent EPA report, a
large improvement in air pollution has occurred in the U.S. since 1970.
Emissions of six principal air pollutants (i.e., SO x , NO x , CO, O 3 , particulate
matter, and lead) have declined 48% since 1970. Sulfur dioxide (SO 2 ) emissions
from power plants are 9% lower than in 2000, and 41% lower than in 1980,
while NO x emissions declined 13% from 2000, and 33% from the 1990 level.
The levels of ground-level O 3 , however, have decreased the least. The ten-year
trend has been relatively unchanged.
7
By contrast, many of the rapidly growing cities in the world are
experiencing an increasing number of environmental problems, especially
those related to air pollution. Serious concerns have been raised about the
health hazards of air pollution in a number of less-developed countries. With
unprecedented growth shown in urban centers, megacities with populations of
10 million or more have emerged in many less-industrialized countries,
including China and India. In India alone there are four such cities, with
three others expected to join the ranks in the next 20 years.
8 In India, a
majority of the 300 million urban dwellers, who constitute 30% of India’s
population, are experiencing deteriorating air quality. Major cities in India are
reportedly among the most polluted in the world, with concentrations of
several air pollutants well above the levels recommended by the World Health
Organization (WHO). Some scientists in the country caution that the residents
of India’s megacities face significant risks to their health from exposure to air
pollutants.
8
As is widely known, China has achieved rapid economic growth during the
past several decades. The growth is coupled with industrialization, accelerated
urbanization, and greatly increased energy consumption.
9 The accelerated
urbanization is evidenced by marked increases in the proportion of urban
population to the total population in China, from 18% in 1978 to 31% in 1999,
a growth rate three times the world average during this period. The explosive
economic growth also made China the world’s second-largest energy
consumer, after the U.S. Energy consumption, especially coal consumption,
is the main source of anthropogenic air-pollution emissions in Chinese cities.
16
Environmental Toxicology
[16:55 26/8/04 P:/CRC PRESS/4365 MING-HO.751 (1670)/4365-002.3d]
Ref: 4365 MING-HO YU Chap-002 Page: 16 13-30
heavy metals, and various kinds of volatile organic compounds (VOCs). The
major source of air pollution is the combustion of fossil fuels for electricity and
transportation, various industrial processes, heating, and cooking. According
to the North American Commission for Environmental Cooperation (CEC),
one-quarter of the industrial pollution released into the North American
environment in 1998 came from U.S. electric power plants. This is closely
followed by pollution from the primary metals sector, the chemical industry,
and the hazardous waste management sectors.
7
2.1.3.2 Air Pollution and Developing Economies
While problems associated with air pollution remain of global concern,
encouraging results were shown for its control in the U.S. and other
industrialized countries. For example, according to a recent EPA report, a
large improvement in air pollution has occurred in the U.S. since 1970.
Emissions of six principal air pollutants (i.e., SO x , NO x , CO, O 3 , particulate
matter, and lead) have declined 48% since 1970. Sulfur dioxide (SO 2 ) emissions
from power plants are 9% lower than in 2000, and 41% lower than in 1980,
while NO x emissions declined 13% from 2000, and 33% from the 1990 level.
The levels of ground-level O 3 , however, have decreased the least. The ten-year
trend has been relatively unchanged.
7
By contrast, many of the rapidly growing cities in the world are
experiencing an increasing number of environmental problems, especially
those related to air pollution. Serious concerns have been raised about the
health hazards of air pollution in a number of less-developed countries. With
unprecedented growth shown in urban centers, megacities with populations of
10 million or more have emerged in many less-industrialized countries,
including China and India. In India alone there are four such cities, with
three others expected to join the ranks in the next 20 years.
8 In India, a
majority of the 300 million urban dwellers, who constitute 30% of India’s
population, are experiencing deteriorating air quality. Major cities in India are
reportedly among the most polluted in the world, with concentrations of
several air pollutants well above the levels recommended by the World Health
Organization (WHO). Some scientists in the country caution that the residents
of India’s megacities face significant risks to their health from exposure to air
pollutants.
8
As is widely known, China has achieved rapid economic growth during the
past several decades. The growth is coupled with industrialization, accelerated
urbanization, and greatly increased energy consumption.
9 The accelerated
urbanization is evidenced by marked increases in the proportion of urban
population to the total population in China, from 18% in 1978 to 31% in 1999,
a growth rate three times the world average during this period. The explosive
economic growth also made China the world’s second-largest energy
consumer, after the U.S. Energy consumption, especially coal consumption,
is the main source of anthropogenic air-pollution emissions in Chinese cities.
16
Environmental Toxicology
[16:55 26/8/04 P:/CRC PRESS/4365 MING-HO.751 (1670)/4365-002.3d]
Ref: 4365 MING-HO YU Chap-002 Page: 16 13-30