Studies related to the effects of CO2 on the our health

 
Let's explore various research findings on why carbon dioxide (CO₂) affects our health.

First, lets look at how different levels of CO₂ concentration impact our health.

Figure 1: Health impacts at various levels of CO₂ concentration (measured using CO₂ detectors).

The Hidden Dangers of Carbon Dioxide (CO₂)

CO₂ is a common gas in the air and a byproduct of numerous processes. While it is essential for various applications, high concentrations can harm health. Controlling CO₂ levels is vital for health and safety.

CO₂, essential for life on Earth, retains solar heat and is a non-flammable inorganic gas at room temperature. It is colorless and odorless, undetectable by human senses, and requires measuring devices for detection. In low concentrations, it is non-toxic, but high concentrations can impair health, causing decreased focus, drowsiness, reduced performance, and even increasing the risk of certain health issues. If CO₂ replaces oxygen, severe oxygen depletion can cause suffocation.

Figure 2: Waking up unrefreshed, partly due to CO₂ build-up in the bedroom.

Excessive CO₂ also harms the environment and is a leading cause of the greenhouse effect, resulting in global warming. As temperatures rise, people increasingly rely on air-conditioned, enclosed spaces that limit fresh air circulation. Poorly ventilated rooms, offices, and vehicles tend to have higher CO₂ levels than outside air, posing even greater health risks.

In 2013, Berkeley researchers conducted a study where participants completed a decision-making task in a simulated organizational crisis under controlled CO₂ levels (600 ppm, 1000 ppm, and 2500 ppm). Results showed significant cognitive decline at 1000 ppm, while at 2500 ppm, strategic thinking and initiative dropped to unusable levels.

Its clear: higher CO₂ concentrations lead to rapid declines in complex problem-solving, strategic thinking, initiative, and situational responsiveness.

Figure 3: Impact of CO₂ concentration on decision-making abilities (Source: Fisk et al., 2013)

Human activities such as burning fossil fuels are increasing atmospheric CO₂, currently around 426 ppm. Without changes, CO₂ levels may reach 1000 ppm by the centurys end and potentially 2500 ppm or more later.

Figure 4: Current CO₂ level of 426 ppm (Source: https://www.co2.earth/), showing a steady increase.

Figure 5: CO₂ emission model projections (Source: Zickfeld et al., 2013), predicting atmospheric CO₂ could reach 2500 ppm or higher if we dont reduce emissions.

Higher CO₂ concentrations lead to blood acidosis and various health issues, including decreased cognitive function. Studies show that increased atmospheric CO₂ correlates with reduced IQ, as illustrated below.

Figure 6: IQ distribution comparison at CO₂ levels of 1000 ppm and 2000 ppm, showing a 5-point drop in IQ (Source: https://psr.org/resources).

Case Study: CO₂ Production During Sleep

Figure 7: Sleeping in a bedroom

Research by Anna Mainka from Silesian University of Technology found that average CO₂ levels in closed bedrooms reached 1,402 ppm for teens and 1,336 ppm for young children. High CO₂ disrupted sleep, causing drowsiness and dizziness. Fresh air improves sleep quality.

Developed countries have air quality standards for CO₂, with legal limits to prevent health risks. CO₂ concentrations over 1,000 ppm cause drowsiness and decreased focus, while also increasing breathing rate, difficulty breathing, and palpitations.

In a theoretical unventilated 20 m³ room, one person could increase CO₂ from 350 ppm to 6,000 ppm over eight hours, with levels rising even faster in crowded spaces.

Indoor CO₂ Levels

CO₂ levels in enclosed spaces such as schools, offices, meeting rooms, bedrooms, classrooms, car cabins, or even airplanes can accumulate over time. While air conditioners or air purifiers may be present, they do not reduce CO₂ unless there is proper ventilation, such as opening doors or windows, or installing an air exchange system. Without adequate ventilation, our breathing causes CO₂ levels to build up, which can impact our health and cognitive abilities.

Figure 8: CO₂ build-up in a car cabin affects the body and mind, causing yawning, drowsiness, headaches, high blood pressure, etc.

CO₂ impacts sleep, especially in unventilated bedrooms. The more people in a room, the higher the CO₂ concentration, which can disrupt sleep quality and negatively impact health, especially in children. As CO₂ levels rise, people experience decreased focus, drowsiness, headaches, increased heart rate, and nausea.

CO₂ Effects on the Brain

Figure 9: CO₂ effects on the brain

We spend 90% of our time indoors in places like homes, offices, schools, and hospitals, breathing in CO₂ without considering air quality. Signs of CO₂ impact include fatigue, drowsiness, and concentration loss in poorly ventilated spaces, indicating COs effects on brain function and productivity. Long-term exposure may be even more harmful.

Studies show indoor CO₂ levels can reach 1500-2000 ppm or higher, depending on the number of people and ventilation, compared to outdoor levels of 350-450 ppm. High indoor CO₂ negatively affects cognition, school learning, and employee performance.

While air conditioning provides temperature comfort, it often circulates stale air without ventilation, which is energy-efficient but increases indoor CO₂. This closed environment contributes to higher CO₂ exposure, impacting overall health.

Figure 10: In a controlled test, a 400 ppm increase in CO₂ decreased cognitive scores by 21%.

CO₂ Health Impacts on Children

Figure 11: CO₂ effects on childrens health

A renowned study by Professor Joseph Allen from Harvards School of Public Health found cognitive function declined by 15% at 950 ppm and by 50% at 1400 ppm, with significant impacts on productivity, learning, and safety as CO₂ levels rise.

Reference

https://bubblynet.com/blog/post/co2-and-wellbeing-part-2


https://axiomet.eu/gb/en/page/1954/air-quality-monitoring-indoors/

https://www.iqhome.org/index.php?route=extension/d_blog_module/post&post_id=17

https://goodtitevs.best/product_details/35975349.html

https://www.advancedsciencenews.com/co2-on-the-brain-and-the-brain-on-co2/

https://gasmonitor-point.co.uk/news/-the-hidden-dangers-of-carbon-dioxide/

https://skepticalscience.com/how-sapiens-in-the-world-of-high-co2-concentration.html

https://www.pranaair.com/blog/harmful-effects-of-carbon-dioxide-co2-on-human-cognitive-function/