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Is CO2 Heavier Than Air? (The Answer Is All Around You)

Is CO2 Heavier Than Air?

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All living creatures need a balance of carbon dioxide (CO2) and oxygen in order to survive. You probably remember this from your grade school science lesson: humans inhale oxygen and exhale carbon dioxide. Carbon dioxide is then absorbed (or inhaled, for a better analogy) by trees so they can release (or exhale) oxygen, which in turn we inhale. So if carbon dioxide is present in the air all around us, it begs the question: is CO2 heavier than air? 

The chemicals that compose CO2 are heavier in terms of density than the elements that make up air. So yes, CO2 is heavier than air. It’s important to understand that CO2 (carbon dioxide) is a chemical compound, while air is a mixture of different elements (like oxygen, nitrogen, carbon dioxide, neon, argon, and hydrogen). We will explore this more in-depth below.

Understanding CO2

Carbon dioxide on its own is about 1.5 times heavier than air. The reason why you don’t see carbon dioxide sinking to the ground is that although there is carbon dioxide present in the air all around us, seeing carbon dioxide in a concentrated form out in nature is quite unusual. 

In a state of non-disturbance (or an extremely concentrated form), carbon dioxide will sink lower to the ground than air.

How CO2 is Formed

How CO2 is Formed

Carbon dioxide is a chemical compound that consists of two oxygen atoms and one carbon atom. This is created by digestion, fermentation, and the decomposition of organic materials. The rise of CO2 in the atmosphere is thought to be the major reason why sea levels are rising, the overall temperature on Earth is increasing, and why storms are harsher. 

However, carbon dioxide is necessary for everyday life because it is utilized by plants and exhaled by animals.

The Danger of Overexposure to CO2

Carbon dioxide is released into the air by human activities and is the number one contributor to human-caused global warming. It is produced when cars and power plants burn fossil fuels such as coal, oil, and gasoline, and the fumes get emitted into the air. High exposure to CO2 will also cause you to feel dizzy, have difficulty in breathing, and even lead to death in extreme cases. That’s why poorly ventilated buildings, spaces, and rooms cause one to feel nauseous and lightheaded. 

CO2 in Everyday Items 

Apart from causing damage to our ozone layer, carbon dioxide is also present in a lot of everyday products. Here are a few examples of common items where you may not have known that a concentration of carbon dioxide is present: 


Ever wondered why beer has suds in it? It’s the carbon dioxide released by the keg when you pour yourself a mugful. It’s also possible to alter the composition of carbon dioxide in your beer by adjusting the pressure and temperature at which you are storing it. 

Dry Ice 

Dry ice is carbon dioxide when frozen or in a solid form. You may have noticed that it does not thaw easily like how normal ice does. And unlike normal ice, which goes back to liquid once it melts, solid dry ice resumes the form of gas once it “melts” (or evaporates). 

Gardens and Greenhouses

As mentioned earlier, plants and trees require carbon dioxide in order to grow and make their own food by the process of photosynthesis, aside from water and sunlight. Carbon dioxide is important to encourage the growth of fuller flowers, leaves, plants, vegetables, and fruits.

You may have noticed that working in an enclosed greenhouse can tire you out rather quickly; this is likely due to the high levels of carbon dioxide that are being released into the air. 

Wine Making

Carbon dioxide is extremely important in the process of winemaking. Unlike the beer industry, carbon dioxide is used in wines in their solid form, which is dry ice. This is to ensure that the flavors and sugar levels in fermented grapes are not altered by any other foreign element.

Imagine using regular ice in fermenting your grapes; the ice would melt and turn into water. The water will most likely combine itself with your grapes, therefore altering the sugar level and flavor of the grape itself. On the other hand, you won’t have the same problem with dry ice. 

Is CO2 Heavier Than Air?

While CO2 is denser than air, it’s important to remember that carbon dioxide itself is not poisonous; rather, it is essential for living things to survive. It’s only when CO2 gets concentrated that we all need to worry because carbon dioxide can’t possibly replace the oxygen that our body needs. 

We should do our best to preserve nature by walking if we don’t need to use our cars, choosing to eat only organic and whole foods, and switching the lights off when not in use. These are simple acts that can reduce the amount of CO2 that is produced and can help reverse some of their damaging consequences to our planet

The Campbells love finding sustainable and fun ways to increase their independence from traditional brick and motor supermarkets. Aquaponics provides a full lifecycle food source for families and a great hobby. #aquaponicslifestyle

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