Composition Of The Atmosphere
The density of the atmosphere decreases with altitude. This does not affect the composition up to an altitude of at least 60 km. Ozone and some trace elements are affected by the chemical reactions in the upper reaches towards 60 km.
Above 70 km the lower force of gravity causes the atmospheric composition to vary with height.
The following percentages show the composition of dry air in the lower levels:
Carbon Dioxide: 0.03%
The graph below represents this composition:
Other trace elements include:
The above list is background information and needn’t be memorised.
The composition of dry clean air shown above does not allow for the effects of water in the atmosphere (up to 4% in volume), dust and smoke, or carbon dioxide.