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Pollution is the introduction of contaminants into the natural environment that cause harm. [1] Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants.
Air pollution is an important risk factor for various diseases, such as COPD (a common lung disease), stroke, heart disease, lung cancer and pneumonia. Indoor air pollution is also associated with cataract. [117] Air pollution has further been linked to brain disorders, such as dementia, depression, anxiety and psychosis. [118]
A pollutant or novel entity [1] is a substance or energy introduced into the environment that has undesired effect, or adversely affects the usefulness of a resource. These can be both naturally forming (i.e. minerals or extracted compounds like oil) or anthropogenic in origin (i.e. manufactured materials or byproducts).
Levels of air pollution rose during the Industrial Revolution, sparking the first modern environmental laws to be passed in the mid-19th century. The environmental movement (sometimes referred to as the ecology movement) is a social movement that aims to protect the natural world from harmful environmental practices in order to create ...
Sources of water pollution are either point sources or non-point sources. [156] Point sources have one identifiable cause, such as a storm drain, a wastewater treatment plant, or an oil spill. Non-point sources are more diffuse. An example is agricultural runoff. [157] Pollution is the result of the cumulative effect over time.
air pollution - the modification of the natural characteristics of the atmosphere by a chemical, particulate matter, or biological agent. albedo - reflectance; the ratio of light from the Sun that is reflected by the Earth's surface, to the light received by it.
A practical definition of water pollution is: "Water pollution is the addition of substances or energy forms that directly or indirectly alter the nature of the water body in such a manner that negatively affects its legitimate uses." [1]: 6 Water is typically referred to as polluted when it is impaired by anthropogenic contaminants.
Looking down from the Hollywood Hills, with Griffith Observatory on the hill in the foreground, air pollution is visible in downtown Los Angeles on a late afternoon.. Air pollution is the introduction of chemicals, particulate matter, or biological materials into the atmosphere that cause harm or discomfort to humans or other living organisms, or damage ecosystems.