Air

Air is the invisible mixture of gases that surround the Earth.  Air contains important substances such as oxygen, carbon dioxide, and nitrogen that most species need to live. Air is also called the atmosphere. However, atmosphere comprises several layers that include the layer that contains what we call air.

The atmosphere is made up of FIVE layers:

Troposphere

  • The altitude is 0 to 12 kilometers 

  • Where we live and where nearly all weather occurs. Contains most of the atmosphere's mass and water vapor.

  • Temperature decreases with altitude

Stratosphere

  • 15 to 50 km in altitude 

  • Contains the ozone layer, which absorbs harmful UV radiation. Commercial jet planes often fly in the lower part for smoother air.

  • Temperature increases with altitude (due to the ozone absorbing UV)

Mesosphere

  • 50 to 85 km in altitude

  • The coldest layer of the atmosphere, with temperatures dropping to about 90°C. Most meteors burn up here.

  • Temperature decreases with altitude

Thermosphere

  • 85 to 1000 km in altitude

  • Experiences extremely high temperatures (hundreds or thousands of degrees) due to absorbing high-energy solar radiation. The auroras (Northern and Southern Lights) occur here.

  • Temperature increases with altitude

Exosphere

  • 1000 to 10,000 km in altitude

  • The outermost layer, where the atmosphere gradually fades into space. Gas molecules are extremely thin and can escape into space. Most Earth satellites orbit here.

  • The temperature is really high here but the air so thin that it will feel cold.

ADDITIONAL IMPORTANT REGIONS

Ozone Layer: A region within the stratosphere with a high concentration of ozone (O3) molecules. Its vital function is to absorb most of the Sun's damaging ultraviolet (UV) radiation.

Ionosphere: Not a distinct layer, but a region encompassing parts of the mesosphere and thermosphere where solar radiation has ionized (charged) gas particles. This region is critical for radio communications and is where the spectacular auroras are created.

WHAT IS IN OUR AIR?

  1. NITROGEN

Nitrogen is one of the most abundant gases in the Earth’s atmosphere. While living things cannot use it directly in the form that it exists in the air, nitrogen is a very important component of all living things. It is necessary to make proteins and DNA.

Humans also use nitrogen for several things:

  • part of chemical fertilizers (NPK)

  • explosives

  • to make fuels for high powered machinery

  • in chemical manufacturing

  1. OXYGEN

Oxygen is considered the most important gas in the atmosphere as all living things need it in order to respire. It is the second most abundant gas in the atmosphere, and forms part of all living things. Oxygen is also a very flammable gas and so, is used in factories to ignite substances.

  1. NOBLE GASES

Noble gases are the gases: helium, neon argon, krypton, xenon and radon. They are called noble gases because they never react to anything. Because of this, they are used in very delicate environments where safety has to be guaranteed. They are used in:

  • lighting (headlights, neon signs)

  • photographic lighting

  • medical imaging

  • welding equipment

  1. CARBON DIOXIDE

Carbon dioxide is made up of carbon and oxygen, which are two of the most important parts of all living things. It is very important because it is needed by plants in order to undergo photosynthesis and make food.

Carbon dioxide does not support fire, and so it is used in fire extinguishers. It is a by product of the burning of fossil fuels, so, it is emitted by cars factory machines, planes, etc.

  1. WATER VAPOUR

Water vapor is the gaseous form of the liquid called water. It is present in very minute amounts in the air, but is still important to living things and t maintaining the balance of the atmosphere. It’s percentage composition in the air determines the amount of rainfall possible as well as humidity levels. In a similar way, transpiration and evaporation levels on the ground determine its percentage in the air.

AIR POLLUTION

Air pollution is the contamination of the air . This reduces the air quality available for living things to breathe in. It also affects the nutrient cycles and the ozone layer, and leads to the greenhouse gas effect that is the cause of global warming. Air pollution is caused by:

  • overuse of transportation that runs on fossil fuels

  • smoking

  • high number of factories

  • mass deforestation

GREEN HOUSE GASES

The green house gas effect refers to the effect that the abundance of certain gases in the atmosphere has on the temperature of the Earth. The way these gases are, when they accumulate in the air, they do not allow heat to escape into space. Instead gets trap in the Earth’s atmosphere, which in turn, drives up the overall temperature of the Earth.

The increase in temperature is what’s known as global warming or climate change. The increase of temperature:

  • melts ice in the poles leading to increased sea and ocean levels.

  • affects the amount of water vapor in the atmosphere, which changes how rainfall, snow, and such natural phenomenon like rainstorms and hurricanes