Who invented the air?

Answer 1

No one invented air.

This is a flawed question. Air was not invented like telescopes or light bulbs were. 'Invent' implies that a person thought of and built it. It is like asking 'Who invented America?' or 'Who invented birds?'. Originally Earth would have had an atmosphere of hydrogen and helium. This is because these were the gasses that just happened to be lying around at the Earth's formation. Hydrogen and helium are very light gasses and easily escape into space, Earth's first 'permanent' atmosphere originated from volcanic eruptions which released ammonia and carbon dioxide. At some point plant life developed and changed the carbon dioxide into oxygen via photosynthesis, and absorbed the ammonia releasing nitrogen. Nitrogen is a very non-reactive gas so the amount of nitrogen in the air doesn't change much and the oxygen is constantly replaced by the action of plants.

The composition of air was worked out by a number of scientists. Most had little idea what they were really doing when they separated oxygen and nitrogen, most experiments involved putting animals in glass bottles and seeing how long they took to asphyxiate.