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 Air Pollution
3. Sources of air pollution

Undesireable materials can be emitted to the atmosphere from either natural or human sources. The air pollution caused by nature is generally small, compared to anthropogenic pollution.

Natural Sources of Air Pollution

Man-Made Air Pollution

3.1.  Natural sources of air pollution

Some of the natural sources of air pollution are organic compounds from vegetation, ground dust, salt spray from oceans, hydrogen sulfides from natural sources, cosmic dust etc. During catastrophes large amount
of gases and ash from volcanic eruptions, gases and smoke from forest, grass, and swamp fires blacken the skies and increase the background pollution levels for years even at points distant from the original
source. Radon, fog and mist, and ozone are the most common natural air pollutants.

3.2  Man-made air pollution

Man-made air pollution sources can be divided into three different groups, as (1) point sources, (2) area sources, and (3) line sources. Industries, power plants, oil refineries etc. with their tall stacks are a major
source of air pollution and are considered to point sources. Residential areas, apartments, office buildings, hospitals, and schools are also major contributors of air pollution. These are area sources of air pollution.
Highways are considered to be line sources of air pollution. Some man-made air pollution sources are motor vehicles, industrial facilities, power plants, space heating, refuse disposal, and transportation services.

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