The topics that air contains a mixture of a giant "sea" of gases that are usually colorless and odorless.
The bulk of what the air contains nitrogen (78%), then it's oxygen (21%), then it is noble gases (0.93%), carbon dioxide (0.04%) finally there is the other gases (0.03 %)
The air surrounding the Earth as a thin layer called the atmosphere. The longer one coming up from the earth's surface the sparser the molecules in the air. The air gets thinner and therefore it is harder to breathe at higher altitudes. There is no clear boundary where the air ends and outer space begins, but at 100 km altitude is customary to say that all the air is for one.
Nitrogen and oxygen in the air
Oxygen is the gas that there are second-most in our air. Oxygen is a basic subject and it consists of one molecule with two atoms in each. We humans need oxygen to breathe and oxygen needed for something to be able to burn, the more oxygen, the better it burns.
The bulk of it in the air is nitrogen. Nitrogen has been named to the gas suffocates fire, animals and humans. Nitrogen is not toxic. Nitrogen is a basic element like oxygen. Nitrogen is used to produce various chemical compounds which can then make fertilizers and dyes with.
How an ozone molecule looks
Ozone is formed when sunlight is strong smashes oxygen molecules high in the atmosphere, then formed the free oxygen atoms. The ozone molecule is formed by a free oxygen (O) atom and an oxygen molecule (O2) hits together (O3). Once they have done that form them an ozone molecule that looks like this:
Human use of gases
Refrigerated, liquid nitrogen is used for example as refrigerants during freeze-drying and transport of food.
Oxygen is used for fighter pilots or sick people who need oxygen. Oxygen is also used to make iron and steel. Noble gases are used to make lighting of various kinds.
An oxide is a chemical compound in which oxygen atoms stuck together with another kind. Oxide comes from the Latin word for oxygen, oxygenium. In the air, we have carbon monoxide, nitrogen oxide and sulfur oxide.
What happens when burned
The substances containing carbon burns very easily as wood, gasoline and plastics. There is plenty of oxygen in combustion, each atom two oxygen atoms to react with, then formation of carbon dioxide (CO2).
When we have eaten dioxide is formed when food is burned in the body. The carbon dioxide leaves the body through the airways
Is there too little oxygen, so that only one oxygen atom reacts with the carbon carbon monoxide (CO), which is toxic.