Is There Too Much Carbon Dioxide in Your Classroom?

Bryan Ng
Readability
6.89

How does this align with my curriculum?

Did you know that too much carbon dioxide in the classroom can affect your body, and even your grades?

You have been stuck in your classroom for the whole afternoon, and there is another half hour until it is time to go home. You have a pounding headache. You cannot focus or think properly. What’s going on?

It just might have something to do with the air you are breathing. Let’s look at what happens to your mind and body when the air you breathe has more carbon dioxide (CO2) than it should.

What happens when you breathe?

Your body uses oxygen to create the energy you need to live. When you breathe air into your lungs, the oxygen in it sticks to your red blood cells. This way, it reaches your organs and muscles.

Through a complex process called cellular respiration, oxygen goes through a series of chemical reactions in order to form energy, CO2, and water vapour. Using that energy, your heart can pump, your brain can think, and your muscles can contract. Meanwhile, the CO2 and water vapour are released back into the environment.

So, what’s the problem?

CO2 is a natural part of the atmosphere. You may have heard that too much CO2 can affect the environment. However, scientists have found too much CO2 can also affect people indoors.

When a room has lots of people and poor ventilation, the concentration of CO2 may get too high.

  • Air is made up of a combination of different gases (not just oxygen!)
  • Nitrogen 
  • Oxygen
  • Argon
  • Xenon
  • Hydrogen
  • Helium
  • Krypton
  • Carbon dioxide

High levels of CO2 in the air can reduce the amount of oxygen you breathe in. That means there is less oxygen going to your brain. If your classroom has too much CO2, you might find it hard to pay attention to your teacher, concentrate on tests, or even stay awake. In one study, scientists found that high levels of CO2 can even make it harder for you to make decisions.

Diagram showing percentages of gases that make up air
Diagram showing percentages of gases that make up air (Source Life of Riley [CC BY-SA 3.0] via Wikimedia Commons).

 

Graph - Text Version

The percentages of gases that make up air. Nitrogen represents more than 78%, Oxygen represents nearly 21%. Xenon, Neon, Hydrogen, Helium, Krypton and Carbon Dioxide make up the remaining percentage.

 

Too much CO2 can also make you feel physically bad. You might start to get a headache, feel dizzy or nauseous, get tired, or have trouble breathing. Poor indoor air quality may also worsen allergies, asthma symptoms and lung health.

Did you know?

The average Canadian spends about 90% of their time indoors.

How much CO2 is too much? 

To put a number to it, the average outdoor atmospheric level of CO2 is around 400 ppm (ppm = parts per million). Different people start to feel the effects at different CO2 levels. Some people start to feel tiredness and other effects at CO2 levels around 1 000 ppm.

What does ppm mean? Parts per million is a unit of concentration. One ppm means that you have one of something in a million of something else. The “something” and “something else” can be measured in molecules, masses, volumes, or whatever else you can think of. Normally, when we are talking about things in the air, we are talking about volumes. That’s why you’ll sometimes see ppmv or parts per million by volume.

Did you know?

One part per hundred (1/100) is more commonly referred to as one percent (%). This comes from the latin word “centum,” which means “hundred.”

Let’s get back to the issue of CO2 in your classroom. Imagine your classroom holds a volume of 1 000 L of air and has a CO2 level of 1 000 ppm.

1 000 L * 1 000 parts/1 000 000 = 1 L (* is another way of representing multiplication)

In other words, there is 1 L of CO2 in the 1 000 L of air in your classroom.

CO2 levels of 1 000 to 2 000 ppm can cause drowsiness. Headaches and other physical effects described above can begin at between 2 000 and 5 000 ppm. More serious, and potentially toxic, effects can happen when CO2 levels are above 5 000 ppm.

How much CO2 is in your classroom?

It is important to maintain low CO2 levels inside. CO2 can be measured using a simple electronic CO2 meter that people can buy in a store or online.

So, when you are sitting in your classroom, how much CO2 are you actually being exposed to? Between 2010 and 2015, 106 Toronto schools had air quality testing done. 43% of those schools had one or more classrooms with a CO2 concentration above 1 000 ppm. This means schools need to do a better job at ventilating some of their classrooms!

Remember, 1 000 ppm is not high enough to hurt you. But it is high enough to cause some physical effects that can affect your grades.

So if you don’t feel well in a classroom, and think the air might have something to do with it, what can you do? You may ask to open a window, leave the door open, or take a break and breathe in the fresh air outside.

CO2 levels affect everyone differently, so not all of your classmates will feel the same way you do. But if CO2 levels are high, chances are, someone else is feeling bad as well. This means that it may be worth mentioning to a teacher or staff member who can find out what is wrong and fix it. Of course, this can happen anywhere, not just in the classroom. So whenever you’re inside, it’s a good idea to take a break every once in a while from your homework (or video games), open a window or go outside.

Starting Points

Connecting and Relating

  • Do you ever notice the air quality when you enter a room? Is it hot, stuffy, dry or humid?
  • Have you ever experienced sleepiness or a headache in class or an indoor environment? If so, what did you think was the cause? How did it affect your ability to do you schoolwork or other tasks?
  • Has the air quality in your house or classroom ever been tested? If so, what was it tested for?
  • Do schools have legally enforced air quality standards that they must meet in order to remain open? Who is responsible for governing and policing these standards?
  • Should governments invest more into testing the quality of air that young people are exposed to in schools? Why or why not?
  • Who is responsible for setting/providing standards or guidelines for indoor air quality? What are acceptable levels for CO2?
  • What are some simple steps that could be taken to improve the air quality in a room?

Connecting and Relating

  • Do you ever notice the air quality when you enter a room? Is it hot, stuffy, dry or humid?
  • Have you ever experienced sleepiness or a headache in class or an indoor environment? If so, what did you think was the cause? How did it affect your ability to do you schoolwork or other tasks?
  • Has the air quality in your house or classroom ever been tested? If so, what was it tested for?
  • Do schools have legally enforced air quality standards that they must meet in order to remain open? Who is responsible for governing and policing these standards?
  • Should governments invest more into testing the quality of air that young people are exposed to in schools? Why or why not?
  • Who is responsible for setting/providing standards or guidelines for indoor air quality? What are acceptable levels for CO2?
  • What are some simple steps that could be taken to improve the air quality in a room?

Exploring Concepts

  • What is the role of CO2 in cellular respiration? What is the chemical reaction that occurs during this process?
  • What factors can contribute to higher levels of CO2 in a room?
  • How is CO2 measured and represented numerically? What tools can be used to test CO2 levels in an indoor space?

Exploring Concepts

  • What is the role of CO2 in cellular respiration? What is the chemical reaction that occurs during this process?
  • What factors can contribute to higher levels of CO2 in a room?
  • How is CO2 measured and represented numerically? What tools can be used to test CO2 levels in an indoor space?

Nature of Science/Nature of Technology

  • Sometimes, in fixing one problem we create another! To make homes and buildings more energy-efficient, engineers and builders have made them tighter, with less air leakage around doors and windows and an increased reliance on central air conditioning. How might society’s energy conservation concerns be creating problems in terms of air quality in indoor environments?

Nature of Science/Nature of Technology

  • Sometimes, in fixing one problem we create another! To make homes and buildings more energy-efficient, engineers and builders have made them tighter, with less air leakage around doors and windows and an increased reliance on central air conditioning. How might society’s energy conservation concerns be creating problems in terms of air quality in indoor environments?

Media Literacy

  • What items in the media have you heard or seen with respect to indoor air quality? What air quality issues are commonly reported?

Media Literacy

  • What items in the media have you heard or seen with respect to indoor air quality? What air quality issues are commonly reported?

Teaching Suggestions

  • Teachers could use this article to support learning about Earth’s atmosphere and gases in the atmosphere. The concepts introduced in the article include carbon dioxide and air quality.
  • After reading the article, students could complete a carbon dioxide Concept Definition Web to build their understanding about this atmospheric gas. Download ready-to-use reproducibles using the Concept Definition Web learning strategy for this article are available in [Google doc] and [PDF] formats.
  • Students could also read the backgrounder Carbon Dioxide on Earth and on the ISS to help develop the Concept Definition Web and further understand the risks of excess CO2 in a closed environment, as on the International Space Station (ISS).
  • If you want to explore this topic further, consider participating in the Living Space action project. In this project, students investigate environmental conditions, such as temperature, humidity, and air quality, in their classroom, and how these relate to health and well-being.

Teaching Suggestions

  • Teachers could use this article to support learning about Earth’s atmosphere and gases in the atmosphere. The concepts introduced in the article include carbon dioxide and air quality.
  • After reading the article, students could complete a carbon dioxide Concept Definition Web to build their understanding about this atmospheric gas. Download ready-to-use reproducibles using the Concept Definition Web learning strategy for this article are available in [Google doc] and [PDF] formats.
  • Students could also read the backgrounder Carbon Dioxide on Earth and on the ISS to help develop the Concept Definition Web and further understand the risks of excess CO2 in a closed environment, as on the International Space Station (ISS).
  • If you want to explore this topic further, consider participating in the Living Space action project. In this project, students investigate environmental conditions, such as temperature, humidity, and air quality, in their classroom, and how these relate to health and well-being.

Learn more

Poor air quality in Toronto schools could impair learning environment (2015)

Article from CTV News looking at the carbon dioxide levels in Toronto classrooms, and the effect that it could have on students.

Carbon Dioxide in Indoor Air (2010)

Information on carbon dioxide and air quality from the National Collaborating Centre for Environmental Health.

Indoor Air Quality in Schools

Information from Berkeley Lab about indoor air quality, and what can cause poor air quality indoors.

Living Space (2018)

Let’s Talk Science's Action Project about living spaces, and how indoor environmental conditions can impact human health.

References

Haverinen-Shaughnessy, U., & Shaughnessy, R. (2015). Effects of classroom ventilation rate and temperature on students’ test scores. PLOS ONE, 10(8). DOI: 10.1371/journal.pone.0136165

The Lung Association. (2019). Indoor Air Quality.

Satish, U., Mendell, M., Shekhar, K., Hotchi, T., Sullivan, D., Streufert, S., & Fisk, W. (2012). Is CO 2 an indoor pollutant? Direct effects of low-to-moderate CO2 concentrations on human decision-making performance. Environmental Health Perspectives, 120(12), 1671-1677. DOI: 10.1289/ehp.1104789

Wisconsin Department of Health Services. (2018). Carbon dioxide.