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What is the Difference Between Air and Oxygen?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

Air and oxygen are sometimes used interchangeably, but the two things are actually different. Oxygen is a pure element, while the air people breathe is a mixture of elements. Although oxygen is necessary for survival, repeated exposure to the pure form could be harmful. The air that makes up Earth's atmosphere has a healthy balance of elements to sustain human life.

Oxygen is a pure gaseous element. Prolonged exposure to it can actually cause brain damage, although the element is sometimes used therapeutically. Most animals require a certain concentration of oxygen in their blood in order to thrive, and for this reason, the gas is used in emergency situations in which access to air is restricted. When used therapeutically, oxygen is usually mixed with other elements.

Oxygen is number eight on the periodic table, which means that it has eight electrons and eight protons. Only a handful of elements, including helium and hydrogen, are lighter. It has a cubic structure and is a totally colorless element.

Air is a mixture of gases, predominately oxygen and nitrogen.
Air is a mixture of gases, predominately oxygen and nitrogen.

The air that people breathe is a mixture that contains primarily oxygen and nitrogen. The nitrogen generally makes up approximately 78%, while oxygen makes up 21%. Other gases, including carbon dioxide, hydrogen, helium, argon, and neon, make up the remainder. These gases dissolve and are carried in the blood.

Anyone who has experienced radical pressure changes is familiar with the effects of dissolved nitrogen in the blood. While this element is normally carried in the blood without any ill effects, extreme depressurization can cause it to form gaseous bubbles. This causes extreme pain and can lead to death from a condition known to divers as the bends.

Oxygen is a pure gas element.
Oxygen is a pure gas element.

The term "air" is also used to refer to the Earth’s atmosphere as a whole, which makes life on Earth possible. Air forms the lower part of the atmosphere, and becomes thinner the further the observer is away from sea level. Thin air refers to that which is less dense than that at sea level. On Earth, people at high elevations experience thin air, which can cause shortness of breath and nausea. It has less oxygen, which means that the body must work harder and breathe more quickly to extract the necessary amount of oxygen.

Divers use various mixtures of breathable gas, including ones that contain oxygen and helium, when they explore the seas.
Divers use various mixtures of breathable gas, including ones that contain oxygen and helium, when they explore the seas.

Most creatures tend to take air for granted, because it is an abundant substance. However, increasing pollution has led to a decline in air quality, which has resulted in health problems for some animals. Air which is heavily contaminated with particles in high concentrations can damage lung tissue. Low quality can sometimes be physically seen in the form of smog, a heavy collection of hydrocarbons in the atmosphere.

Frequently Asked Questions

What is the primary difference between air and oxygen?

Pollution leads to a decline in air quality.
Pollution leads to a decline in air quality.

Air is a mixture of gases that make up the Earth's atmosphere, with oxygen being just one component. While oxygen is a single type of molecule (O2), air contains roughly 21% oxygen, 78% nitrogen, and 1% other gases such as argon, carbon dioxide, and trace amounts of other elements.

Can we breathe pure oxygen, and if not, why?

Breathing pure oxygen for short periods can be tolerated, but prolonged exposure can be harmful, leading to oxygen toxicity. Our bodies are adapted to the air's natural composition, and high concentrations of oxygen can damage lung tissues and disrupt the balance of other gases in our bloodstream.

How does the oxygen content in the air affect human health?

People at high elevations experience thin air, which can cause shortness of breath.
People at high elevations experience thin air, which can cause shortness of breath.

Oxygen content in the air is crucial for human health as it is necessary for cellular respiration. According to the World Health Organization, maintaining a proper balance of oxygen in the air we breathe is essential for sustaining life and avoiding health issues such as hypoxemia, which can occur if air has too little oxygen.

Why is nitrogen important in the air if we don't use it for breathing?

Nitrogen is important because it dilutes the oxygen in the air, making it safe for us to breathe. Without nitrogen, the high concentration of oxygen would be toxic. Additionally, nitrogen is essential for plant growth and is a fundamental component of the ecosystem, as it is a building block of amino acids and proteins.

How does altitude affect the composition of air and oxygen availability?

As altitude increases, the air pressure decreases, which means that the same volume of air contains fewer oxygen molecules. This can lead to altitude sickness due to lower oxygen availability for breathing. However, the actual percentage composition of oxygen in the air remains roughly the same at about 21%.

What role does oxygen play in combustion and how does this relate to air composition?

Oxygen is a key element in combustion, as it reacts with a fuel source to produce fire. In air, the 21% oxygen content is sufficient to support burning. If the oxygen concentration is too low, combustion may not occur, while environments with pure oxygen can lead to rapid, uncontrollable fires due to increased reactivity.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a AllThingsNature researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a AllThingsNature researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

anon978595

What elements are in air?

behaviourism

When I was a child I thought that the air was entirely oxygen. It wasn't until I was in middle school or so that I studied things like atmosphere and realized that actually, oxygen is not a very big part of our atmosphere at all. Considering how many people do not study much science or remember what they had to learn, it is no surprise how little most of us know about the differences between oxygen and air.

Catapult

@donna61- your comment on exercise and high elevation is really important for professional athletes. I have read about many elite runners in particular who will move to high-elevation areas to train, because it forces them to work towards a higher cardiac efficiency. Then, when those athletes compete, especially in places with lower elevation, they will be that much stronger and better.

donna61

I experienced this first hand when I moved from Florida to Colorado. Within one hour I experienced altitude sickness. It is very unpleasant and will stay with you about a week, until your body adjusts to the oxygen level at the higher altitude.

Interestingly, I did not experience this a few years ago when we went from a higher elevation to a lower one.

Another thing that less oxygen effects is your ability to exercise. At sea level I thought I was in great shape. Moving to a higher elevation, I have discovered that I am out of shape, and I need to work slowly back up to where I was in my exercise routine.

My doctor said this is very normal for people moving from a lower elevation to a higher one.

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    • Air is a mixture of gases, predominately oxygen and nitrogen.
      By: Luiz
      Air is a mixture of gases, predominately oxygen and nitrogen.
    • Oxygen is a pure gas element.
      By: nmcandre
      Oxygen is a pure gas element.
    • Divers use various mixtures of breathable gas, including ones that contain oxygen and helium, when they explore the seas.
      By: eothman
      Divers use various mixtures of breathable gas, including ones that contain oxygen and helium, when they explore the seas.
    • Pollution leads to a decline in air quality.
      By: corepics
      Pollution leads to a decline in air quality.
    • People at high elevations experience thin air, which can cause shortness of breath.
      By: DURIS Guillaume
      People at high elevations experience thin air, which can cause shortness of breath.