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buildings. Exposure to asbestos through inhalation has shown a higher than expected
incidence of bronchial cancer. Various technologies for the control of airborne asbestos
have been reported in US EPA Report No. TS-799 (28), a United Nations report (27),
and elsewhere (29–32).
Air toxics emit from existing point and area sources. Large point sources include
chemical plants, petroleum refineries, and power plants. The small point sources of air
toxic emission, such as dry cleaners, are more widespread than large point sources. Air
toxics emissions are also attributed to waste-management sources; the US EPA OSW
has shown that there are 2600 to 3000 potential TSDFs.
Acute (short-term) or chronic (long-term) exposure to an air pollutant has charac-
teristic health effects. The neurological, respiratory, and reproduction systems can be
affected by exposure to air toxics. Exposure to benzene, for instance, can result in
cancer. The US EPA has developed two methods to identify or quantify the impact of
carcinogenic air toxics: individual risk and population risk. Individual risk is expressed
as a statistical probability to show an individual’s increased risk of contracting cancer
when exposed to a specific concentration of a pollutant over a 70-yr lifetime. Population
risk, which is expressed as number of cancer incidences per year expected nationwide,
shows the risk as result of exposure to a pollutant.

9.4. Greenhouse Gases Reduction and Industrial Ecology Approach
9.4.1. Industrial Ecology
Industrial ecology seeks to balance industrial production and economic performance
with the emerging understanding of both local and global ecological constraints. As a
result, industrial ecology is now a branch of systems science for sustainability, or a frame-
work for designing and operating industrial systems as sustainable and interdependent
with natural systems (33).
9.4.2. Global Warming
Over the past 50 yr, global warming has been attributed to greenhouse gases, such as
carbon, water vapor, methane, nitrogen dioxide, CFCs, and so forth. It has been projected
that average temperatures across the world could climb between 1.4ºC and 5.8ºC over the
next century. A major cause for this projected global warming is the increased carbon
dioxide emission by industries and automobiles. At the source, carbon dioxide emission
can be easily removed from industrial stacks by a scrubbing process that utilizes alkaline
substances. The long-term effect of global warming, projected in the UN Environmental
Report released in February 2001, may cost the world about $304 billion (US) a year
down the road. This projected cost is based on the following anticipated losses: (1) human
life loss and property damages as a result of more frequent tropical cyclones; (2) land loss
as a result of rising sea levels; (3) damages to fishing stocks, agriculture, and water
supplies; and (4) disappearance of many endangered species (33).
According to a 2001 Gallup poll, 57% of Americans surveyed stated that where eco-
nomic growth conflicts with environmental interests, the interest of the environment should
prevail. On the other hand, the same survey discovered that only 31% of those polled think
global warming would pose a serious threat to themselves or their way of life. The results
of this poll indicate that both environmental and economical interests are important to