Air and Atmosphere - Composition of Air

Air is a mixture of gases, primarily composed of Nitrogen ($N_2$), Oxygen ($O_2$), Carbon dioxide ($CO_2$), Water vapor ($H_2O$), and noble gases like Argon ($Ar$).

Nitrogen ($N_2$) makes up about $78\%$ of the air. It is relatively inactive and helps in controlling the rate of combustion.

Oxygen ($O_2$) makes up about $21\%$ of the air. It is vital for respiration in living organisms and is a supporter of combustion.

Carbon dioxide ($CO_2$) is present in a very small amount (approx $0.03\%$ to $0.04\%$). It is essential for photosynthesis and contributes to the greenhouse effect.

The presence of water vapor ($H_2O$) in the atmosphere is responsible for weather phenomena and determines the humidity of a place.

Noble gases like Argon ($Ar$), Helium ($He$), and Neon ($Ne$) are present in traces, making up about $0.9\%$ of the atmosphere.

Air also contains varying amounts of dust particles, smoke, and pollutants depending on the location and environment.