A pollutant or novel entity is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource. These can be both naturally forming or anthropogenic in origin. Pollutants result in environmental pollution or become public health concerns when they reach a concentration high enough to have significant negative impacts.
Surface runoff, also called nonpoint source pollution, from a farm field in Iowa, the United States during a rainstorm. Topsoil, as well as farm fertilizers and other potential pollutants, runoff unprotected farm fields when heavy rains occur.
The night sky viewed from Luhasoo bog, Estonia with light pollution in the background
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance or energy. Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants.
Litter on the coast of Guyana
Smog in the center of Moscow, Russia in August 2010
An industrial area, with a power plant, south of Yangzhou's downtown, China
A litter trap catches floating waste in the Yarra River, east-central Victoria, Australia.
