Causes of Pollution

New inventions and processes have been continuously developed to improve our way of life. Such developments are called technological ad­vances. Technological advances help us, but many of them also bring about harm to the environment. In addition, there are economic and social causes of pollution.

Technological causes. Many environmental pollution problems are a result of the rapid advances in technology that have been made since about the end of World War II (1945). Technological advances in agriculture, industry, and transportation have greatly improved our way of life. But most of the advances were made without consideration of the effects they would have on the environment.

The automobile engine is an example of a very useful technological development that harms the environment. Through the years, automobiles have been made more and more powerful. Many cars being built today have two to three times as much power as most cars built during the 1940s.

Because of this, the new cars produce much more polluting exhaust than the older ones did. In order to make engines more powerful, automobile manufacturers increased the pressure and — as a result — the temperature at which combustion takes place in the engines' cylinders. The higher temperatures during combustion cause chemical reactions that put large amounts of nitrogen oxide gases into the engines' exhausts. In addition, high compression engines require special gasolines that burn evenly to prevent "knocking" noises. Mechanisms called catalytic converters now remove some of the polluting materials produced by automobile engines. Also, the gradual elimination of the lead from gasoline has helped make automobiles less polluting. However, there is still much to do to eliminate pollution from automobiles. An increase in their number may cancel gains from using catalytic converters and unleaded gasoline.

The sewage treatment plant is an example of a technological develop­ment that was designed to protect the environment, but which can cause pollution nevertheless. Most treatment plants prevent dangerous organic wastes (wastes from animal and plant matter) from upsetting the natural cycles in water. The treatment plants use bacteria and oxygen to break down the organic wastes and turn them into inorganic nutrients. But when the nutrients are put into the water, they upset natural cycles by increasing the growth of algae. Scientists and engineers are working to develop sewage treatment plants that will also remove inorganic nutrients from sewage.

Some products of advanced technology contribute to environmental pollution in more than one way. For example, plastics are a troublesome solid waste because they will not break down and cannot be absorbed by the soil. Plastics also indirecdy cause pollution when they are produced. Large amounts of electricity are required in order to produce plastics. As a result of this need for electricity, the production of plastics helps create a demand for more electric power plants. Electric power plants that burn fuel, such as coal, are a major source of air pollution.