The presence of ozone is important because it shields living organisms from some harmful radiation from the Sun.
As it happens, the vibrational frequency of the atoms in ozone matches that of UV light, consequently it protects organisms on earth by absorbing (in the upper atmosphere) most of the UV radiation before it hits people and other living things here on the surface. Unfortunately ozone in the lower atmosphere is actually harmful to most living things since it is very reactive. It irritates our respiratory systems and eyes as well as attacking cellular membranes of plants and participating in reactions that produce other types of pollution.
It helps people breath.
oxygen
Ozone is an important form of oxygen. It forms a miracle layer in atmosphere.
The most important elements in the Earth's atmosphere are N (nitrogen) and O (oxygen).
The most important gases when studying the atmosphere are nitrogen and oxygen (as O2 and O3).
Earth's atmosphere is mainly nitrogen, oxygen, carbon dioxide, and water vapor. Oxygen is the most reactive of these. Oxygen allows all of the life as we know it on earth. Even though oxygen is less than 1/4 of the atmosphere it is the most important part.
Oxygen is important because us humans have to breath and our brain have to function.
Nitrogen and Oxygen
The essential gas is oxygen...
I'd say the most important gasses in the Earth's atmosphere are oxygen and water vapour.
Oxygen
the atmosphere is important because without the atmosphere the oxygen would escape from our atmosphere into space and without the atmosphere we would all dye because there would be nothing to protect us from the suns heat
Oxygen is necessary for most organisms to carry out their life functions.