air

(ār)

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[Gr. aēr, air]
The invisible, tasteless, odorless mixture of gases surrounding the earth. Air at sea level consists of approx. 78% nitrogen and 21% oxygen by volume. The remaining constituents are water vapor, carbon dioxide, and traces of ammonia, argon, helium, neon, krypton, xenon, rare gases, and some pollutants.

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