Just wanted to write to say after reading this article I went out and bought a CO2 meter. Levels in my house were high enough to effect drowsiness and trouble

Just wanted to write to say after reading this article I went out and bought a CO2 meter. Levels in my house were high enough to effect drowsiness and trouble concentrating. (> 1100ppm, even with the window cracked) Subsequently decided to leave my sliding glass door open all day, allowing levels to drop to around 550ppm. Haven't felt this alert and active in ages. What the hell have I been doing to myself?