This article will provide you with answers to the most frequently asked questions about compressed air, allowing you to gain an understanding of everything you need to know!

Table of Contents

What is in Compressed Air? What is Compressed Air Made of?

Compressed air ingredients are the exact same as the air surrounding us that we breathe in and out every day. The difference is that the compressed air is forced into a smaller size and kept under pressure so becomes unbreathable. When you take atmospheric air and force it into a smaller volume, the molecules take up less space and so, the air is now compressed.

What’s in compressed air, is just like what’s in atmospheric air:

  • 78% Nitrogen
  • 21% Oxygen
  • 1% Other Gases

What is in compressed air doesn’t change from atmospheric air when it is compressed, just the amount of space the molecules take up does!

What is Compressed Air?

Whether you are aware or not, compressed air is all around us, from balloons being blown at birthday parties to the air in tires of cars of bicycles! It quite possible was used to help manufacture whatever devices you’re reading this on.

Compressing air is to literally force atmospheric air into a smaller space and as a result, brings the molecules closer to each other. It then stores this energy created for future use. Compressed air is a very good medium for storing and transmitting energy. It’s flexible, versatile, and relatively safe compared to other methods for storing energy, like batteries and steam for instance.

How Does Compressed Air Work?

So, how do you compress air? The way compressed air works is that when it is forced into a smaller space, and the molecules are brought closer together, the kinetic energy of the air increases. This energy that gets released when doing this is also equal to the energy required to force the air into the smaller space, and so, the compressed air stores the energy for future use.

When called upon, the energy of the compressed air is transferred elsewhere to provide power to complete a certain task. For instance, when blowing up a balloon, the air gets forced into a smaller volume, and so, the energy required to inflate the balloon is equal to the energy contained in the compressed air. Or, when operating an impact wrench in a mechanical environment, for the tool to operate effectively it needs the required amount of pressurized/compressed air.

Why is Compressed Air Hot?

Compressed air is hot because the temperature of the air is directly proportional to the mean kinetic energy of its molecules. So as the air is compressed and the molecules begin to move faster, the kinetic energy and the resulting temperature will increase. This is known as the “heat of compression”.

Though, when compressed air leaves an air compressor, it is not as hot as it is in the compression chamber. This is because the air has had time to cool down either in the storage tank or through an aftercooler.

How is Air Compressed?

Air is compressed in two very simple steps:

  1. First the air is sucked in through an intake and trapped in a cylinder, tank or some form of container
  2. Then the space becomes smaller, which forces the air molecules closer together

The air is now compressed and will remain trapped in its smaller state until it’s ready for use. There are numerous styles of air compressors on the market, each with varying methods of compressing air. To learn more about each, visit our type-specific pages:

The YouTube demonstration below provides useful animations on how reciprocating, diaphragm and rotary compressors compress air.

How Much Can Air Be Compressed?

Atmospheric air is around 14.7 PSI (pounds per square inch), or 14.696 PSI to be precise, and is capable of being compressed to a pressure of up to 6004 PSI when forced into a smaller state during the compression stage. The exact amount of how much air can be compressed and pressurized is determined by science.

What Causes Pressure in Compressed Air?

Air pressure is typically explained by the following three scientific laws: The first law of thermodynamics, Boyle’s law, and Charles’ law. The first law of thermodynamics states that an increase in pressure equals a rise in heat and that compressing air creates a proportional increase in heat during the compression stage. Boyle’s law states that if a volume of air halves during compression, the pressure is doubled, and, Charles’ law states that the volume of air changes in direct proportion to the temperature.

So what we have here, is that the three laws together state that pressure, volume, and temperature are proportional. If you alter one of these values, then one or two of the others are going to change too. This can best be described using the volume formula:

(P1 * V1) / T1 = (P2 * V2) / T2

Where:
P = Pressure
V = Volume
T = Temperature

On the left-hand side of the formula, we have the initial state of the air, and on the right, the final state after a change. With air compressors, the air volume and pressure can be controlled and increased where needed. Luckily, you don’t need to know this formula as it’s as simple as setting the pressure you require on an air compressor and science does the rest.

Why Do We Need Compressed Air?

First of all, compressed air accounts for about 10% of the global energy currently used within industries. You may not realize it, but compressed air plays a vital role in the majority of products available in the market. Somewhere within their process, compressed air was utilized.

It’s described as the fourth utility, behind electricity, petroleum, and gas. The main difference between compressed air and these other sources is that users of compressed air are able to easily generate their own supply and choose how to generate it. For this reason, compressed air is capable of accommodating various applications in various environments. Air compressors can be configured to compress air at specific pressures, at a certain flow, and of the right quality.

Why Do We Use Compressed Air?

One of the most important reasons that people use compressed air instead of electricity is for safety concerns. Electrical equipment poses a safety hazard in applications where equipment becomes overloaded. Compressed air and pneumatic tools can be used under many conditions, such as on wet floors or in high humidity areas, while electrical shocks or even fires may occur in these conditions if electricity is used. This can lead to damages to equipment, property, and even personnel.

In addition to that, compressed air is far more flexible. For remote areas like construction sites and mines, it is easier to use. Air tools boast the advantages of being able to run cooler and have variable speed and torque. Now, consider some form of impact-type equipment… It would be almost impossible to develop an equivalent force with electricity, especially in these remote areas.

Compressed air-powered tools also tend to be far more lightweight. They can easily be manufactured with materials that make them lightweight and more ergonomic. And so, they balance the cost of air with the cost of labor due to reduced worker fatigue because of using these lighter tools.

Finally, there’s the cost. The cost equivalent of compressed air can be up to 7 to 8 times higher than that of electricity. However, the equipment designed to use compressed air is far lower in cost. A lot fewer parts are used due to the simplicity of the design and, pneumatic tools last longer in production environments due to their ruggedness.

What is Compressed Air Used for?

Compressed air is typically used as either an energy source or for active air. When used as the former, compressed air is capable of powering air tools and production equipment. These tools and equipment are used tremendously across dozens of applications in many industries which include construction, factory product, industrial processes, and maintenance. You’ll even find roller coasters at your nearest theme park using compressed air!

Active air is used when a steady stream of air is required for a task. Tonnes of industries from pharmaceutical and chemical companies to food and beverage factories use active air in their processes to produce the highest-quality goods and services.

What Are the Benefits of Using Compressed Air?

Using compressed air has many benefits, and there are reasons why it has become such a popular energy source. The main benefits include:

  • Cheap power source
  • Compact, light and easy to move
  • Energy efficicent
  • Improved productivity
  • Lower theft rates
  • Low operating costs
  • Versatile tools & applications

Why is Compressed Air Quality Important?

Compressed air can contain unwanted substances or contaminants, for example, water in droplet or vapor form, oil in a droplet or aerosol form, as well as dust and even rust. Depending on the compressed air’s application, these substances can impair production results and even result in increased operating costs. When it comes to spray painting, if water or another contaminant was in the compressed air stream then the quality of the paint finish is bound to be hindered by patchiness or watermarks.

The purpose of compressed air treatment is to produce the compressed air quality specified by the consumer, usually of the highest quality possible. When the role of compressed air in a process is clearly specified, finding the system that will be the most profitable and efficient in that specific situation is a simple process.

It is a question, for users, to establish whether the compressed air will come into direct contact with the product (like with spray painting) or whether, for example, oil vapor or mist can be accepted in the working environment because it will not have detrimental effects. A systematic method is required to select the right equipment to ensure that the requirements of the compressed air quality are met.

What Contaminants Do We Find in Compressed Air?

The most common contaminants found in compressed air are dry & wet dust, water in both liquid and vapor form, oil in both liquid (aerosol) and vapor (hydrocarbon) form as well as rust which is typically caused by the presence of water. Because of this, it’s important to have the necessary components in your compressed air system to ensure the compressed air is as pure as possible. These might include but are not limited to:

The YouTube video below by Parker discusses the 10 main compressed air contaminants in detail.

Is Compressed Air Safe?

Compressed air is one of the cleanest, safest, simplest, and efficient energy sources available when used properly. It doesn’t release any dangerous fumes or other harmful by-products and is non-combustible. However, compressed air can become dangerous if it is misused or if the systems are not maintained properly (especially the air receiver tank). Therefore, compressed air users should follow all guidelines provided to them!

Can You Breathe Compressed Air?

Compressed air is only breathable if it has undergone sufficient and significant air treatment. You cannot simply breathe air from an air compressor and this sort of air is not suitable for human breathing. So, only when the compressed air leaving the compressor has then been treated with a multi-stage breathing air filter, is it possible to breathe the air without risking any harm to yourself.

The YouTube video below demonstrates the breathing air filtration products available for compressed air.

https://www.youtube.com/results?search_query=breathing+compressed+air

What Happens if You Breathe in Pressurized Air?

If you were to breathe in compressed air straight from the compressor, a depression of oxygen levels will occur in your body as the fumes go into your lungs and then your central nervous system. This will lead to you finding it impossible to breathe and eventually suffocating.

Can Compressed Air Kill You?

Compressed air is safe to use if used properly. If you were to mess around with it or use it in unconventional ways it can be very dangerous and even deadly. How much compressed air can kill you? It won’t take a lot, and it can do so in any of the following ways:

  • Compressed air can blow eyes out of their sockets
  • Compressed air blown into an ear can ruptrue eardrums and cause brain damage
  • Compressed air blown into the skin can obstruct an artery and result in embolism
  • Inhaling compressed air can rupture your lungs or esophagus

I mean, these situations are very rare but it’s good to be aware that they’re possible so you ensure you use compressed air safely. You should never point compressed air directly at a person or clean your clothes with it, and abiding by this should make the above injuries preventable. Canned air can also potentially kill you due to the chemicals inside the air.

Can Compressed Air Explode?

Yes, it is possible that your air receiver tank that holds compressed air will explode – of course, this is a rare situation but it has happened! Take a look at the image below for proof.

Blown Compressor Tank
Blown Compressor Tank

Why do air compressors explode? The most common reason for an air compressor tank to explode is corrosion which is caused by water build-up. If the tank is not drained regularly then water is allowed to accumulate inside the tank which will lead to corrosion, eventually weakening the tank to a point that it explodes when compressed air is inside it.

Another quite common reason for tanks to explode is simply down to the manufacturing defects. It’s important to use reputable air receiver tanks to ensure that these types of explosions don’t occur.

What is Canned Air? & What is in a Can of Compressed Air?

Compressed air cans, or otherwise known as canned air or gas dusters, are used to provide a pressurized blast that knocks loose dust and dirt from keyboards, clears out computer vents, and even opens up tight apertures in an SMT (surface mount technology) stencil. Canned air most commonly contains the chemicals difluoroethane, trifluoroethane, tetrafluoroethane, or butane.

Can Canned Compressed Air Explode?

Yes, canned compressed air is more likely to explode than normal compressed air become they’re not the same. Canned air contains highly flammable chemical mixtures which of course, gives them a higher chance of exploding.


If you have any questions about compressed air, please leave a comment below, with a photo if applicable so that someone can help you!