LARGE-SCALE EFFECTS OF AIR
POLLUTION
Large-Scale Effects
The tall smokestacks used by industries and utilities do not remove pollutants
but simply boost them higher into the atmosphere, thereby reducing their
concentration at the site. These pollutants may then be transported over
large distances and produce adverse effects in areas far from the site
of the original emission. Sulfur dioxide and nitrogen oxide emissions
are causing acid rain. The pH level, or relative acidity, of many freshwater
lakes has been altered so dramatically by this rain that entire fish populations
have been destroyed. These effects also occur in Europe. Sulfur dioxide
emissions and the subsequent formation of sulfuric acid can also be responsible
for the attack on limestone and marble at large distances from the source.
The worldwide increase in the burning of coal and oil since the late
1940s has led to ever increasing concentrations of carbon dioxide. The
resulting "greenhouse effect", which
allows solar energy to enter the atmosphere but reduces the reemission
of infrared radiation from the earth, could conceivably lead to a warming
trend that might affect the global climate and lead to a partial melting
of the polar ice caps. Possibly an increase in cloud cover or absorption
of excess carbon dioxide by the oceans would check the greenhouse effect
before it reached the stage of polar melting. Nevertheless, research reports
indicate that the greenhouse effect is definitely under way and that the
nations of the world should be taking immediate steps to deal with it.
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