The atmosphere is essential for any life to survive on Earth. Without it, there is little chance of any living organism surviving. Earth’s atmosphere is a vast shell of gas that envelops the entire planet. Within this shell, we survive, but all our activities are restricted. It consists of different gases, water vapor, and tiny particles suspended in the gaseous matter of the air.
What is the Atmosphere?
Earth is a unique planet where life exists. Air is one of the necessary conditions for life on this planet, a mixture of several gases surrounding the Earth. The air that surrounds the Earth is known as the atmosphere.
Structure of Atmosphere:
Earth’s atmosphere consists of several layers, each with different properties. The layers rising above the Earth’s surface are called the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. The exosphere slowly dissolves into interplanetary space.
Troposphere:
It holds 80% of the mass at 11 km, with a surface warmed by solar energy and intense vertical currents, where most meteorological events occur. It is the lowest layer of the atmosphere, stretching from the Earth’s surface to the lower limit of the stratosphere, rich in water vapor and significantly influenced by pollution.
Stratosphere:
Gentle vertical movements, primarily influenced by radioactive mechanisms, heated by ozone’s absorption of solar ultraviolet (UV) radiation, exhibiting the highest (lowest) temperatures at the summer (winter) poles. Situated above the troposphere and beneath the thermosphere, this layer is called the mesosphere, extending from 12 to 50 km.
Mesosphere:
Heat warmed by solar radiation at the bottom of the atmosphere, its coldest region (temperatures between -2 and 92 °C), is dissipated upwards by vertical movement at altitudes between 40 and 80 km.
Thermosphere:
The upper part of the atmosphere above the mesosphere has extremely low mass and is the most heated area (up to 1200 °C).
Exosphere:
The top layer of the atmosphere contains atomic and ionic H2, O2, and He.
Origins of the Atmosphere:
- When Earth formed 4.6 billion years ago, its atmosphere was likely composed primarily of hydrogen (H) and helium (He), as well as hydrogen compounds such as methane (CH4) and ammonia (NH3).
- These gases eventually escaped into space.
- The release of gases from rocks during volcanic eruptions (so-called outgassing) was the main source of atmospheric gases.
- The primordial atmosphere produced by outgassing consisted mainly of carbon dioxide (CO2), some nitrogen (N2), and water vapor (H2O), along with trace amounts of other gases.
Importance of the Atmosphere:
- Oxygen is essential for living things.
- Carbon dioxide is very valuable to plants.
- Dust particles present in the atmosphere create favorable conditions for precipitation.
- The amount of water vapor in the atmosphere is constantly changing, which has a direct impact on plants and living things.
- Ozone acts as a shield for all living beings against the damaging ultraviolet rays of the sun.
Composition of the Atmosphere:
The atmospheric envelope around the Earth is a mechanical mixture of numerous gases and other substances that are crucial to all life on Earth. Four major gases – nitrogen, oxygen, argon, and carbon dioxide – make up 99.99% of the total volume of dry air. Nitrogen has the highest concentration at over 78%, while oxygen makes up just under 21%.
| Groups | Gases | Volume % of dry air |
| Major Gases | Nitrogen | 78.084 |
| Oxygen | 20.9476 | |
| Argon | 0.934 | |
| CO2 | 0.04 | |
| Minor Gases | Methane | 0.002 |
| Neon | 0.001818 | |
| Helium | 0.000524 | |
| Krypton | 0.000114 | |
| Hydrogen | 0.00005 | |
| Xenon | 0.0000087 | |
| Ozone | 0.00006 | |
| Variable Gasses | Water vapor | Variable amount |
| Dust particles | Variable amount | |
| Aerosols | Variable amount |
Human Activity on Earth’s Atmosphere:
Human activities release six major greenhouse gases into the environment. Three of these gases are also found in nature: carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). The remaining three, hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6), are produced exclusively by humans (which is why they are called “anthropogenic”).
HFCs, HFCs, and SF6 occur in much lower concentrations than the others, but their mighty and long-lasting effects make them significant.
Conclusion:
The atmosphere serves as a dynamic framework that supports life on our planet. Its importance in providing the air we breathe and controlling the Earth’s climate should be emphasized. Yet human activities disrupt its balance, and joint efforts are essential to maintaining it. Recognizing its importance and taking proactive measures will ensure this vital resource can continue giving life to future generations.
