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Composition of Earth’s Atmosphere

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he Earth’s atmosphere is a thin layer of gases that surrounds it and is kept in place by gravity. This layer is vital for maintaining the planet’s ecosystem by supplying the air necessary for respiration, regulating its temperature, and safeguarding it from harmful radiation. Nitrogen and oxygen constitute approximately 99% of the Earth’s atmospheric volume, with the remaining 1% comprising various gases such as argon, carbon dioxide, neon, helium, methane, and ozone, whose concentrations can fluctuate depending on location and time. Any variations in the composition of these gases can have a significant impact on the environment and climate of the Earth.

Composition of Earth's Atmosphere

Composition of Earth’s Atmosphere

Salient Facts About Earth’s Atmosphere

The important features of the atmosphere which surrounds the Earth are as follows:

  1. The thickness which is present of the earth’s atmosphere is about 480 km. About 99 percent of the total thickness lies up to the height of about 32 km above the earth’s surface.
  2. The pressure of air decreases with an increase in altitude.
  3. The atmosphere of Earth is a mixture of gases that helps in the sustenance of life on Earth.
  4. The gravity on the surface of the earth helps in holding the atmosphere in place.
  5. One of the most important roles of the atmosphere is to sustain the entry of ultraviolet rays to the surface of the earth.

According to NASA, the composition of the atmosphere of Earth are as follows:

  1. Nitrogen- About 78 percent
  2. Oxygen- About 21 percent
  3. Argon- About 0.93 percent
  4. Carbon Dioxide- About 0.04 percent
  5. Certain amounts of other gases like neon, helium, methane, krypton, and hydrogen along with hydrogen is found.

Composition of Earth’s Atmosphere

The Earth is enveloped by a thin layer of gases, known as the atmosphere, that is vital for sustaining life on the planet. The composition of the atmosphere is predominantly nitrogen and oxygen, accounting for approximately 99% of its total volume. The remaining 1% consists of various gases like carbon dioxide, helium, neon, and methane, as well as water vapor in varying amounts depending on weather conditions. Changes in the atmospheric composition can significantly impact the environment and climate of the planet, leading to increased temperatures, altered precipitation patterns, and more frequent and severe weather events. 

Hence, it is essential to monitor and regulate human activities that contribute to these changes, such as the burning of fossil fuels and deforestation, to ensure a sustainable future for the Earth. The composition of the earth’s atmosphere is due to the by-product of the life it holds. As the activities of humans have a great impact on the composition of Earth’s atmosphere which goes up to 10,000 kilometers above the ground beyond which it, merges into space. 

Oxygen

Oxygen is one of the most important gases for the survival of humans but it is a very small part of the gases present in the atmosphere as it is only 21 percent of the total gases present. It is a very common misconception that trees or forests are the main sources of oxygen, but oceans are the main source of oxygen. 

Carbon- Dioxide

Carbon- dioxide consists of 0.03 percent of the atmosphere and plants use carbon dioxide in the making of oxygen and also plays a significant role in the outgoing terrestrial radiations as well as remains transparent for the solar radiations which come inside. It is one of the significant gases responsible for the formation of Greenhouse Gases.

Nitrogen

Nitrogen is a gas that is found mostly in the atmosphere covering up to 78 percent. The most abundant element in the Earth’s atmosphere is nitrogen, which makes up approximately 78% of its total volume. Nitrogen is a gas that has no color, odor, or taste and is crucial in building proteins and nucleic acids, which are essential for life. 

Ozone Gas

The ozone gas is present around 10-50 km above the surface of the earth and acts as a shield by absorbing the UV radiations from the sun and also reverts back the harmful rays from reaching the surface of the earth.

Other gases

The rest of the gases together make up to 1 percent of the atmosphere which includes 0.93 percent argon and 0.04 percent carbon dioxide and many other gases. The percentage of carbon dioxide has been increasing throughout the years due to the activities of humans. Though the composition of Carbon Dioxide may seem very low from the figures it is on a constant rise and it is of huge danger to humans as it has been the reason for the constant increase in the earth’s temperature and causing a greenhouse effect. The increase in the level of carbon dioxide is due to the increased emissions of vehicles and industries. The 1 percent also contains water vapors, helium, and other noble gases. 

The amount of water present in the atmosphere is very less and is dependent on a number of factors. It is mostly absent in the atmosphere, but the concentration is high where the climate is humid. Though it is very less in quantity it is the most important part of the atmosphere other than oxygen. While a lot of gases are present in the atmosphere the number of suspended particles can’t be neglected. The suspended particles are called Aerosols .it may include soil from desert salt particles due to the evaporation of salt water, plant pollens, and a lot more particles. When a volcano eruption takes place the fine particles of lava or magma are suspended in the air. They have a huge impact on the atmospheric heat balance, cloud formation, and many more properties.

Structure of the Earth’s Atmosphere

The atmosphere on Earth can be divided into five different layers which depend on the different temperature conditions:

  1. Troposphere
  2. Stratosphere
  3. Mesosphere
  4. Thermosphere
  5. Exosphere
Earth's Atmosphere

Earth’s Atmosphere

Troposphere

It is the lowest layer in the Earth’s atmosphere. and closest to the ground. It reaches 15 kilometers from the earth’s surface. Almost 75 percent of the mass of the atmosphere is from this part due to the heavy gases. The troposphere is found to be thick at the equator and thin at the north and south poles due to the difference in Gravity at the poles and the equator. The clouds are found in the area and so does all the activities of the weather. Air is warmer at the bottom and as the height increases the temperature decreases this is true not only for the Troposphere but also for most of the other layers. 

Stratosphere

It is the layer directly above the Troposphere. It reaches from the top of the troposphere to  50 kilometers above the ground. It has the highest concentration of oxygen and even the ozone layer is present in the stratosphere. The ozone layer is very important for the survival of humans as it protects us from the harmful UV rays emitted by the sun and prevents various health diseases like skin cancer etc.

Mesosphere

It is the layer above the stratosphere and is about 83 kilometers above the Stratosphere. The concentration of oxygen and nitrogen is high in this layer and the concentration of water vapor is almost null. The Temperature decreases with the increase in altitude till this point in the atmosphere, the coldest point in the earth’s atmosphere is at the top of the Mesosphere. The reason it increases after this point is that the gases above it absorbed solar radiation It is also the place where most meteors burn up before reaching the ground.

Thermosphere

It is the layer above the Mesosphere and reaches from the top of the Mesosphere to 600 kilometers above the earth’s surface. The temperature of this region is generally very high due to the absorption of solar radiation emitted by the sun, which can go up to 2,000 degrees. Atomic oxygen takes up most of the area at this level and is present in its lone form as an atom.

Exosphere

It is the layer above the Thermosphere. It is the uppermost layer in the Earth’s atmosphere. Due to very low gravity, the gas molecule escapes into outer space. The air in this layer is extremely thin and it merges with the space in the end.

Related Links

  1. Composition and Structure of the Atmosphere
  2. Natural Environment

FAQs on the Composition of the Earth’s Atmosphere

Q 1. What was the original composition of Earth’s atmosphere?

Answer-

The original composition of Earth’s atmosphere is composed of hydrogen and helium.

Q 2. What is the importance of the atmosphere?

Answer-

The importance of atmosphere is that it protects us from any harmful ultraviolet solar radiations which is prevalent.

Q 3. What is the composition of the Earth’s atmosphere?

Answer-

The composition of earth’s atmosphere include nitrogen, oxygen, argon, carbon dioxide and other gases.



Last Updated : 11 May, 2023
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