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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 can occur naturally or be caused by human activities. [4] Air pollution causes around 7 or 8 million deaths each year. [5] [6] It is a significant risk factor for a number of pollution-related diseases, including heart disease, stroke, chronic obstructive pulmonary disease (COPD), asthma and lung cancer.
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Main list: Lists of English words Quebec French • Language teaching terms and ideas • Rhetorical terms • Alternative words for British • Greek words for love • Case-sensitive English words • Chicano Caló words and expressions • Dacian words • English words containing Q not followed by U • English words with disputed usage • French words of Arabic origin • Frequently ...
List of mathematical constants (typically letters and compound symbols) Glossary of mathematical symbols; List of physical constants (typically letters and compound symbols) List of common physics notations (typically letters used as variable names in equations) Rod of Asclepius / Caduceus as a symbol of medicine
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).
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.
Water pollution also reduces the ecosystem services such as drinking water provided by the water resource. 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.