UCSB Science Line
Sponge Spicules Nerve Cells Galaxy Abalone Shell Nickel Succinate X-ray Lens Lupine
UCSB Science Line
How it Works
Ask a Question
Search Topics
Our Scientists
Science Links
Contact Information
What is in Carbon Dioxide that can kill you?
Question Date: 2005-10-27
Answer 1:

There’s actually nothing about carbon dioxide that kills you. It’s the gas that companies put into soda to make it bubbly! Carbon dioxide is also in the air that we breathe every day. However, if you were in a room of just carbon dioxide, you would die because of the lack of oxygen! This would be the same if you were in a room with any other gas.

Carbon dioxide is slowly killing our planet though because it is a greenhouse gas, which means it absorbs a lot of the sun’s heat that leads to global warming.

You might be thinking of another similar gas that is poisonous called carbon monoxide. There is a protein in our blood called hemoglobin that is responsible for transporting oxygen throughout our body. Hemoglobin does this by binding to oxygen and carrying it around when our heart pumps blood throughout our body. However, carbon monoxide binds to hemoglobin a lot better than oxygen does, which prevents your body from getting the oxygen it needs to function.

Answer 2:

Humans like fish, amphibians, reptiles and other mammals obtain energy by using chemical reactions that require oxygen. This oxygen is taken in from air which is 78% Nitrogen and 21% oxygen. The process is called respiration. Without oxygen (O2), an animal can only survive for a few minutes. CO2 is a molecule and the oxygen that makes it up can NOT be used in the process of respiration.

In fact CO2 is a waste product that leaves our body when we exhale. The reaction that gives our cells energy that uses O2 has CO2 as a waste product; so we get rid of it when we exhale.

Answer 3:

Hi Brittany! Carbon dioxide (CO2) in itself is not poisonous, it is even necessary for life on earth, as plants need CO2 for photosynthesis. As it comes to human health, it's only when CO2 gets concentrated (a lot higher CO2 level than normal) that it can have an effect.

When we are thinking about indoor CO2 level, the main creator is actually your body, as you breathe in oxygen (O), and release CO2. Other sources of indoor CO2 can include smoking and open flames like a gas stove or a fireplace. This released CO2 will increase the CO2 concentration in a closed room. As a CO2 level in a closed room increases, it replaces the oxygen your body needs and when your body doesn't have enough oxygen, it does not function properly. The symptoms include fatigue, loss of focus, headache, and tiredness. The easiest remedy is to open the windows or step outside for a few minutes. Good ventilation is key!

As for what can kill you, I wonder whether you were thinking of carbon monoxide (CO), which is indeed a toxic gas. The reason why carbon monoxide is much more dangerous is that carbon monoxide outcompetes oxygen in the lung as you breathe. So even a very small level of CO can cause all the symptoms mentioned above and a higher level of CO can lead to a carbon monoxide poisoning, where carbon monoxide builds up in your body and there is not enough oxygen for you, which can potentially lead to death. That is why we have a carbon monoxide detector in our houses to let us know when the CO level might be too high. It is pretty scary, but it is very rare, and good ventilation can always help you out!


Answer 4:

Carbon dioxide (CO2) is a molecule consisting of 1 carbon atom (C) and two oxygen atoms (O). At room temperature, it is a gas and is found in normal air with concentrations of 0.04 %. At concentrations that low and even up to about 5 % it has little to no toxicological effects. However, if humans inhale higher concentrations of over 5 %, CO2 can cause two diseases called hypercapnia and respiratory acidosis.

If the human body realizes the abnormal high level of CO2 in its blood, it initiates a reflex that increases the breathing frequency in order to exchange the CO2 from the blood with the air (exhale it) and infuse the blood with more oxygen (inhale it). If the hypercapnia is caused by high CO2 concentration in the air, this reflex followed by increased breathing will increase the blood CO2 level even further. This eventually leads to something called respiratory acidosis. The CO2 reacts with the water in the blood and forms carbonic acid (H2CO3). Increased amounts of this acid can cause long term damage to organs, like the kidneys, and will result in death in really high concentration. This means that there is nothing in carbon dioxide that kills humans. It is the gas itself that changes the acidity of the human blood and can influence the chemistry of the body so much that it is deadly. However, the typical concentrations in the air we breathe are harmless.

Answer 5:

Hi Brittany, there's nothing intrinsically dangerous at all about carbon dioxide. Really, it's what's not in carbon dioxide that can kill you: oxygen. Humans need to breathe in oxygen in order to keep our cells functioning properly and feed the many simultaneous biological processes occurring within our bodies. Without any oxygen, humans will suffocate and die.

Our bodies take in oxygen that goes from the lungs to the bloodstream and produce carbon dioxide and water through the process ofcellular respiration. When the cell has consumed the input oxygen, it releases carbon dioxide back into our bloodstream that is then transported back to the lungs and exhaled. Without oxygen, cellular respiration can not take place and a person's cells will begin to die, ultimately causing the person to die too. Our need for oxygen is the distinguishing feature between aerobic and anaerobic organisms: we, as aerobic organisms, require oxygen to survive while anaerobic organisms do not. In summary, there is nothing dangerous about carbon dioxide itself; we as humans, however, need to breathe in oxygen to continue to survive.

Answer 6:

Carbon dioxide can't kill you in and of itself. It's not a breathable gas; you still need oxygen to live. However, carbon dioxide itself is not poisonous.

Excess carbon dioxide is harmful to the environment in two ways. First, it is a greenhouse gas, and as a result increasing the amount of the stuff in the atmosphere will change the world's climate, possible in a way that is bad for us. Second, carbon dioxide can combine with water to form carbonic acid. While a weak acid, carbonic acid does lower the pH of the oceans, which can be bad for marine life in a number of ways.

Answer 7:

A big problem with CO2 (carbon dioxide) is this: when the air has lots of CO2, there's less oxygen (O2), and we need O2 for breathing. CO2 is heavier than O2 - there are 3 atoms in each CO2 molecule and only 2 atoms in each O2 molecule, so the CO2 settles near the ground instead of going up into the atmosphere.

Another problem with CO2 is that it makes the blood too acidic when it reacts with H2O (water). CO2 + H2O = H2CO3 (carbonic acid).

Click Here to return to the search form.

University of California, Santa Barbara Materials Research Laboratory National Science Foundation
This program is co-sponsored by the National Science Foundation and UCSB School-University Partnerships
Copyright © 2020 The Regents of the University of California,
All Rights Reserved.
UCSB Terms of Use