Pollution

Nowadays one of the major problems around the world is pollution. Pollution is the principal of contaminants in the environment that causes disorder, harm or discomfort to the ecosystem.
Pollutioncan take the form of chemical substances or energy, such as noise, heat, or light.
Pollutants are the elements of pollution, they can be foreign substances or energies, or naturally occurring; theyare considered contaminants when they exceed natural levels.
The Blacksmith Institute issues annually makes a list of the world's worst polluted places. In the 2007 issues the ten top nominees arelocated in Azerbaijan, China, India, Peru, Russia, Ukraine and Zambia.
In the late industrial age, the term overpollution was common, representing a view that was both critical of industrial pollution,but likewise accepted a certain degree of pollution as nominal industrial practice.

Ancient cultures

Air pollution has always been with us. There were found on ceilings of prehistoric caves thatprovides evidence of the high levels of pollution associated with inadequate ventilation of open fires. The forging of metals appears to be a key turning point in the creation of significant airpollution levels outside the home. Core samples of glaciers in Greenland indicate increases in pollution associated with Greek, Roman and Chinese metal production.

Sources and causes

Air pollutioncomes from both natural and man made sources. Though globally man made pollutants from combustion, construction, mining, agriculture and warfare are increasingly significant in the air pollutionequation.
Motor vehicle emissions are one of the leading causes of air pollution. China, United States, Russia, Mexico, and Japan are the world leaders in air pollution emissions. Principal pollutionsources include chemical plants, coal-fired power plants, oil refineries, petrochemical plants, nuclear waste disposal activity, incinerators, large livestock farms (dairy cows, pigs, poultry, etc.), PVC...