Man-Made Causes of Air Pollution

By Mark Orwell
Industrial smog and smoke is a major source of air pollution.
Thinkstock/Comstock/Getty Images

Man is responsible for most of the world's air pollution, both indoors and outdoors. Everything from smoking a cigarette to burning fossil fuels tarnishes the air we breathe and potentially causes health problems as minor as a headache to as harmful as respiratory, lung and heart disease. The issues related to air pollution are addressed by ongoing efforts across the globe that seek to mitigate health and environmental problems. These include American governmental programs aimed at cleaning the air to primary-school volunteer sampling groups throughout Eastern Europe. With luck, efforts like these will one day lead to healthier air.

Types of Pollutants

Man is at least partially at fault for most of the world's major air pollutants. Carbon monoxide, a colorless and odorless gas, is the most widely distributed of these. Carbon dioxide is also highly prevalent. Nitrogen oxide and dioxide, while both natural components of the Earth's atmosphere, are found in greater amounts due to human actions and are the cause of smog and acid rain. There are also chlorofluorocarbons, which were used as refrigerants and aerosol propellants. These damage the ozone layer, which is why the Environmental Protection Agency banned them in 1978.

Causes of Air Pollutants

The single largest source of air pollutants is the burning of fossil fuels such as coal and gasoline. Fossil fuels are used for heating, to operate transportation vehicles, in generating electricity, and in manufacturing and other industrial processes. Burning these fuels causes smog, acid rain and greenhouse gas emissions. It also disperses some heavy metal contaminants and increases the amount of soot in the air. Power plants and factories emit much of the sulfuric air pollutants. In all, developed nations -- particularly the United States and the Soviet Union -- are responsible for the majority of the world's air pollutants.


Smog is one of the most dangerous air pollutants to humans and other biological organisms. It is made when coal and oil containing minor amounts of sulfur are burned. The oxides of these sulfur particles form sulfuric acid, which is toxic to life and damaging to many inorganic materials. Air pollution can damage human life, especially in major cities where there is a conglomerate of industries and fumes from vehicles. It is also harmful to plants. Sulfur dioxide, nitrogen oxides and peroxyacl nitrates enter leaf pores and damage plants that way. Pollutants also break away the waxy coating of leaves that prevent excessive water loss, causing further damage to crops and trees that are important to the surrounding environment.

Extreme Cases

When man-made pollution aggregates over a large city with a large population, the dangers are many. There are two instances of major pollution-related deaths and illnesses occurring over a short period of time. They best show how badly pollution affects humans over a short period as well as a long one. The first occurred in Donore, Pennsylvania, in 1948. A period of several days with stagnant air created a high pressure system that contained dangerous levels of smog over the city for extended periods of time. It caused 20 deaths and 6,000 cases of illness. In London, in 1952, the same situation caused between 3,500 and 4,000 deaths in five days. While air pollution illnesses and deaths usually don't occur over such short periods of time, these are examples of worst-case scenarios with the possibility of occurring again if air pollution isn't mitigated.