Earth’s Atmosphere Composition: Nitrogen, Oxygen, Argon and CO2
Some people are surprised to learn that oxygen isn’t the most abundant gas in Earth’s atmosphere composition.
Based on the relative volumes of the gases in Earth’s atmosphere, nitrogen is actually more than 3 times more than oxygen.
Because the troposphere is the lowest atmosphere layer, it contains 75 percent of the atmosphere’s mass.
From largest to smallest, Earth’s atmosphere composition contains nitrogen, oxygen, argon, CO2 and trace gases. Because water vapor is highly variable geographically, it’s excluded from this total.
1. Nitrogen (78.1%)
While nitrogen is the most abundant gas in Earth’s atmosphere, it only makes up 0.005% of Earth’s crust in weight (David Darling).
Nitrogen is incredibly stable and requires a lot of energy to change forms.
Even though its volume in Earth’s crust is relatively small, nitrogen plays an important role in the nitrogen cycle.
As part of this cycle, nitrogen constantly exchanges between the atmosphere and living organisms.
2. Oxygen (20.9%)
Earth has the conditions for life to flourish. Oxygen is essential to human life as our lungs respire oxygen and uses it in metabolism.
While nitrogen is an extremely stable gas, it’s difficult to break up and use for chemical processes. But oxygen will readily take part in chemical reactions because it’s an electron thief.
So even though nitrogen is plentiful, we need oxygen to drive chemical reactions that produce energy.
3. Argon (0.93%)
As an inert gas, argon doesn’t bond or do much in the atmosphere.
This is why there’s no argon cycle. But we have nitrogen and carbon because of their ability to bond with other elements.
When potassium radioactively decays, argon is one of the possible product. And the lithosphere has lots of potassium.
It’s not too exciting of a gas. But it’s up in the atmosphere at 0.93% of air volume.
4. Carbon Dioxide (0.04%)
Carbon is the most important element for building molecules essential for living things.
As you can see from the long-term carbon cycle, carbon takes up various forms such as carbon dioxide (CO2), methane (CH4) and glucose (C6H12O6).
Since 1900, carbon dioxide has increased mostly because of human activity. After extracting fossil fuels, humans burn fossil fuels.
In turn, gases like methane and carbon dioxide become air pollution in the atmosphere. In fact, carbon dioxide has nearly doubled since 1900.
5. Trace Gases
The remaining portion of the atmosphere belongs to trace gases. For example, neon, helium, methane, methane, and krypton are some of the major trace gases that make up a small part of the atmosphere.
But humans can also cause some trace gases. For example, chlorofluorocarbons (CFCs) has damaged the ozone layer in the north and south pole.
When chlorine enters the troposphere and eventually the stratosphere, it reacts with ozone (O3) essentially depleting it. Similar to ozone, water vapor is a variable gas.
6. Water Vapor (Variable)
Water vapor has been removed from the 100% total because of its region variability. But it can make up large portions of the atmosphere. For example, it can make up 5% by volume in hot regions but much less in colder regions.
Water vapor regulates air temperature because it absorbs solar radiation. It evaporates from lakes and rivers from the surface of Earth. Once it’s in the atmosphere, water vapor condenses such as in the form of rain. It simply changes form from water vapor to a liquid.
As part of the hydrological cycle, water is always in motion. And it’s all driven by the sun’s energy.
The main focus is how water is stored – in the atmosphere, glaciers, oceans, plants and humans. Most evaporation takes place at oceans. It’s the Coriolis effect that moves it away from the equator.
What is the distribution of gases in the atmosphere?
In this video, it displays a year in the life of Earth’s carbon dioxide. As you can see, carbon dioxide is the most important gas affected by human activity.
In the northern hemisphere, we see the highest concentrations of carbon dioxide from major emission sources. For example, carbon emissions are mostly focused around North America, Europe, and Asia. But the gas disperses, finding its circulation path with global weather patterns and ocean currents.
Even the seasonal patterns on Earth affect the amount of carbon dioxide in the atmosphere. During photosynthesis in spring and summer, plants absorb a substantial amount of carbon dioxide from the atmosphere.
As summer transitions to fall, photosynthesis begins to decrease as carbon dioxide accumulates back into the atmosphere. This effect is from the Earth metabolism or net primary productivity.
Earth’s Atmosphere Composition
The Earth’s atmosphere is made up of many different gases. At the lower levels, nitrogen and oxygen are the most abundant gases. If you want to learn more about our atmosphere and beyond, try out some of the courses below:
One of the most important things to remember about Earth’s atmosphere is that it is dynamic, meaning what we see today may not be the same as what we see years from now. Do you have any comments or questions? Please let us know in the comment form below.
At 0.04% of the atmosphere will let you think for yourselves if a gas can have such an impact. Must be pretty toxic, yes i just exhaled some of it a sec ago! At 0.02% CO2 plants die! and industrial greenhouses pump it x5 if they want increased yield. Even Patrick Moore one of the greenpeace founders talks about the CO2 scam. There are many scientists on the logical side, check youtube.
Thank you. This is really helpful for my science project.
If the environmentalists could succeed in ridding the atmosphere of CO2, all plant life would die, swiftly followed by all large animal life. It would be left to decay bacteria living off the corpses to replenish the Earth and restart evolution from a low level.
This says Atmospheric carbon has doubled since 1900. As it states Carbon is 0.04% that means in 1900 it was 0.02, which in turn means due to plant life depletion (which would happen if carbon was that low) the carbon reduction would not be reversible. This would mean what carbon we have (or had) would escape the atmosphere and we would all be looking forward to having a planet just like Mars. Given the scaremongering here can’t manage the simple stuff, I wouldn’t trust the rest of it too much.
Forget it Clint, you’ll never convince their closed minds. Its years and years of programming.
As almost 1% of the atmosphere is Argon, I wonder how it is distributed in the atmosphere from the ground to TOA. Is it more abundant, in terms of consentration/ppmv, at the ground than the upper atmosphere? It is a heavy gas that does not mix with other gases, with at molar mass at 40g/mol, more than twice as heavy as air (16g/mol), I would assume it was more abundant at the lower atmosphere, but is this correct?
Under the Obama administration the EPA convinced the Supreme Court that Carbon Dioxide should be considered a pollutant and regulated under the Clean Air Act. That then let the EPA set emission standards for CO2 that eliminated any coal-fired power generation.
Sorry to break it to you but carbon dioxide is not a pollutant! That is shear propaganda.