Page 105 - Fundamentals of Air Pollution

I. General 75

given off by the trees of the forest (1). Another air pollutant problem, which
can be attributed to plant life, is the pollens which cause respiratory distress
and allergic reactions in humans.
Other natural sources, such as alkaline and saltwater lakes, are usually
quite local in their effect on the environment. Sulfurous gases from hot
springs also fall into this category in that the odor is extremely strong when
close to the source but disappears a few kilometers away.

B. Anthropogenic Sources
1. Industrial Sources

The reliance of modern people on industry to produce their needs has
resulted in transfer of the pollution sources from the individual to industry,
A soap factory will probably not emit as much pollution as did the sum
total of all the home soap-cooking kettles it replaces, but the factory
is a source that all soap consumers can point to and demand that it be
cleaned up.
A great deal of industrial pollution comes from manufacturing products
from raw materials—(1) iron from ore, (2) lumber from trees, (3) gasoline
from crude oil, and (4) stone from quarries. Each of these manufacturing
processes produces a product, along with several waste products which
we term pollutants. Occasionally, part or all of the polluting material can
be recovered and converted into a usable product.
Industrial pollution is also emitted by industries that convert products
to other products—(1) automobile bodies from steel, (2) furniture from
lumber, (3) paint from solids and solvents, and (4) asphaltic paving from
rock and oil.
Industrial sources are stationary, and each emits relatively consistent
qualities and quantities of pollutants. A paper mill, for example, will be in
the same place tomorrow that it is today, emitting the same quantity of
the same kinds of pollutants unless a major process change is made. Control
of industrial sources can usually be accomplished by applying known tech-
nology. The most effective regulatory control is that which is applied uni-
formly within all segments of industries in a given region, e.g., "Emission
from all asphalt plant dryers in this region shall not exceed 230 mg of
particulate matter per standard dry cubic meter of air."

2, Utilities
The utilities in our modern society are so much a part of our lives that
it is hard to imagine how we survived without them. An electric power
plant generates electricity to heat and light our homes in addition to provid-
ing power for the television, refrigerator, and electric toothbrush. When
our homes were heated with wood fires, home-made candles were used