Atmosphere consists of a lot of trace gasses. Some of the major trace gases in the atmosphere are Argon which constitutes 0.93%, Carbon Dioxide constituting 0.035%, Neon, Methane, Helium, Ozone, Hydrogen, Krypton, Xenon, Nitrous Oxide, Iodine, Carbon Monoxide and Sulphur Dioxide.
In addition to these trace gases we also find water vapour and solid particles in the atmosphere. Although the amount of water vapour is quite less in the atmosphere, the variation in amount of water vapour affects the weather conditions to a great extent.
Some of the gases in the atmosphere are called variable gases because they vary from place to place. These variable gasses are Water Vapour, Carbon Monoxide, Sulphur Dioxide, Nitrous Oxide and Methane.
Some gases are called as Greenhouse Gases because they have a tendency to absorb long wave radiation from the sun and retain the heat in the atmosphere. Excess amounts of greenhouse gases in the atmosphere is the main reason for global warming.
We are aware that Carbon Dioxide is produced by burning fuel. Trees and plants absorb Carbon Dioxide from the atmosphere and replace it with Oxygen.
Ozone is found in the upper atmosphere and helps in absorbing ultraviolet radiation from the sun. Ozone is found approximately at around 10 to 50 kilometres from the surface of earth. The maximum concentration of ozone is found at 20 to 25 kilometres from the earth surface.
In addition to the various gasses, there are a lot of suspended particles in the air. Solid particles like sea-salt and dust causes visibility problems like smog.