Carbon dioxide (CO₂) is a natural part of the air, but too much of it indoors can make us feel tired, foggy, or even sick. It’s not poisonous like carbon monoxide, but it’s a helpful indicator of ventilation quality.

Where does CO₂ come from?

• Every time we breathe, we exhale CO₂.
• High levels are most common in crowded rooms or homes with poor ventilation.
• Combustion (burning fuel) can also produce CO₂ indoors.

Why it matters:

When CO₂ levels rise, oxygen levels effectively drop. This can lead to:

• Fatigue or drowsiness
• Headaches
• Brain fog and difficulty focusing
• Increased heart rate in some individuals