How Carbon Dioxide Affects Indoor Air Quality

The air we breathe is becoming polluted every day. One factor contributing to the bad air quality is the presence of Carbon Dioxide in the environment. In this post, we look at how Carbon Dioxide affects indoor air quality.

What is carbon dioxide?

Carbon dioxide (CO2) is a colorless, odorless, non-flammable gas naturally occurring in the atmosphere.

Where does CO2 come from?

CO2 is a natural constituent of the air we breathe; it is a colorless, odorless, and non-flammable gas produced by metabolic processes (such as respiration) and by the combustion of fossil fuels. 

The average outdoor air concentration of CO2 is 300 to 400 ppm. Indoor levels are usually higher due to the CO2 exhaled by building occupants.

Human metabolism alone can lead to CO2 levels over 3,000 ppm, especially in poorly ventilated rooms. Indoor combustion appliances, particularly gas stoves, can also increase CO2 levels.

How Carbon Dioxide Affects Indoor Air Quality

CO2 is frequently an issue in the context of indoor air quality concerns. It is relatively easy to measure and is commonly included in indoor air quality monitoring. 

CO2 at indoor levels does not pose a direct health risk. However, elevated CO2 levels (e.g.,> 1100 ppm) may suggest the need for more ventilation. 

Indoor CO2 levels are generally higher than outside, as building occupants produce CO2 when they exhale.  Ventilation exchanges indoor and outdoor air and reduces indoor CO2 levels. 

High indoor CO2 levels may indicate that the air exchange rate is too low for the number of people in the room.

The best way to combat this is to increase ventilation by turning up mechanical ventilation systems or opening windows. 

What are the health effects of Carbon Dioxide?

CO2 is considered to be minimally toxic by inhalation. Its primary health effects result from its behavior as a simple asphyxiant.

A simple asphyxiant is a gas that reduces or displaces the normal oxygen in breathing air. Symptoms of mild CO2 exposure may include headache and drowsiness.

At higher levels, rapid breathing, confusion, increased cardiac output, elevated blood pressure, and arrhythmias may occur.

Breathing oxygen-depleted air caused by extreme CO2 concentrations can lead to death by suffocation.

What are the symptoms of different levels of exposure?

300-400ppm Normal background concentration in outdoor ambient air
400-1,000ppm Concentrations typical of occupied indoor spaces with good air exchange
1,000-2,000ppm Complaints of drowsiness and poor air.
2,000-5,000 ppm Headaches, sleepiness, and stagnant, stale, stuffy air may also be present. Poor concentration, loss of attention, increased heart rate, and slight nausea may also be present.
5,000 Workplace exposure limit (as 8-hour TWA) in most jurisdictions.
>40,000 ppm Exposure may lead to serious oxygen deprivation, resulting in permanent brain damage, coma, and even death.

 

FAQ: How Carbon Dioxide Affects Indoor Air Quality

How does carbon dioxide harm the air?

Carbon dioxide in the atmosphere warms the planet, causing climate change. Human activities have raised the atmosphere’s carbon dioxide content by 50% in less than 200 years.

What is the CO2 limit for air quality?

Normal outdoor air contains around 400 ppm of CO2. Guidelines state that CO2 levels below 1000 ppm are often considered a marker for good indoor air quality.

Maintaining CO2 levels below this threshold ensures better ventilation and higher comfort for occupants.

What are the effects of high carbon dioxide levels in the air?

Symptoms of mild CO2 exposure may include headache and drowsiness. At higher levels, rapid breathing, confusion, increased cardiac output, elevated blood pressure, and arrhythmias may occur.

Breathing oxygen-depleted air caused by extreme CO2 concentrations can lead to death by suffocation.

How can I reduce high household CO2?

  • Make sure you have proper ventilation. Open windows often and run fans to circulate air. 
  • Incorporate live plants in your home. 
  • Keep your HVAC well maintained with regular service and new air filters. 
  • Air purifiers.

What should CO2 levels be in a room?

Occupied spaces with good air exchange usually have 400-1,000 ppm.

What can an excess of CO2 in the air cause?

Carbon dioxide is a greenhouse gas, and an increase in the amount of carbon dioxide in the atmosphere would cause more heat to be retained by the atmosphere and lead to global warming.

How Can I monitor indoor air quality at my home or office?

We recommend using an indoor air monitor, the Qingping Air Monitor 2. The Qingping Air Monitor 2 provides real-time monitoring of seven metrics, including temperature, humidity, CO2, Noise, and Temperature.

indoor air quality monitor

 

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