Page 102 - Fundamentals of Air Pollution

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Sources of Air Pollution

I. GENERAL

The sources of air pollution are nearly as numerous as the grains of sand.
In fact, the grains of sand themselves are air pollutants when the wind
entrains them and they become airborne. We would class them as a natural
air pollutant, which implies that such pollution has always been with us.
Natural sources of air pollution are defined as sources not caused by people
in their activities.
Consider the case in which someone has removed the ground cover and
left a layer of exposed soil. Later the wind picks up some of this soil and
transports it a considerable distance to deposit it at another point, where
it affects other people. Would this be classed as a natural pollutant or an
anthropogenic pollutant? We might call it natural pollution if the time span
between when the ground cover was removed and when the material
became airborne was long enough. How long would be long enough? The
answers to such questions are not as simple as they first appear. This is
one of the reasons why pollution problems require careful study and analy-
sis before a decision to control them at a certain level can be made.

A. Natural Sources

An erupting volcano emits particulate matter. Pollutant gases such as
SO 2/ H 2 S, and methane are also emitted. The emission from an eruption

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