Changes

==Etymology==

==Etymology==

[https://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English], from Anglo-French, from [[Latin]] aer,  from [[Greek]] aēr

[https://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English], from Anglo-French, from [[Latin]] aer,  from [[Greek]] aēr

*Date: [http://www.wikipedia.org/wiki/14th_Century 14th century]

*Date: [https://www.wikipedia.org/wiki/14th_Century 14th century]

==Definitions==

==Definitions==

*1 a archaic : [[breath]]  

*1 a archaic : [[breath]]  

*10 : the height achieved in [[performing]] an aerial maneuver <a snowboarder catching big air>; also : the maneuver itself

*10 : the height achieved in [[performing]] an aerial maneuver <a snowboarder catching big air>; also : the maneuver itself

==Description==

==Description==

'''Air''' is mainly composed of nitrogen, oxygen, and argon, which [[together]] [[constitute]] the major [[gases]] of the [[atmosphere]]. The remaining [[gases]] are often referred to as trace gases, among which are the [http://en.wikipedia.org/wiki/Greenhouse_gas greenhouse gases] such as water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Filtered air includes trace amounts of many other [http://en.wikipedia.org/wiki/Chemical_compound chemical compounds]. Many [[natural]] substances may be present in tiny amounts in an unfiltered air sample, including dust, pollen and spores, sea spray, volcanic ash, and meteoroids. Various industrial [http://en.wikipedia.org/wiki/Pollutant pollutants] also may be present, such as chlorine  (elementary or in compounds), fluorine  compounds, elemental mercury, and sulfur compounds such as sulfur dioxide [SO2].

'''Air''' is mainly composed of nitrogen, oxygen, and argon, which [[together]] [[constitute]] the major [[gases]] of the [[atmosphere]]. The remaining [[gases]] are often referred to as trace gases, among which are the [https://en.wikipedia.org/wiki/Greenhouse_gas greenhouse gases] such as water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Filtered air includes trace amounts of many other [https://en.wikipedia.org/wiki/Chemical_compound chemical compounds]. Many [[natural]] substances may be present in tiny amounts in an unfiltered air sample, including dust, pollen and spores, sea spray, volcanic ash, and meteoroids. Various industrial [https://en.wikipedia.org/wiki/Pollutant pollutants] also may be present, such as chlorine  (elementary or in compounds), fluorine  compounds, elemental mercury, and sulfur compounds such as sulfur dioxide [SO2].

[[Category: Earth Science]]

[[Category: Earth Science]]