CO₂ is not toxic at the concentrations you will ever encounter indoors. It is, however, a near-perfect proxy for how much of the air in the room is recycled human breath.
Harvard's COGfx study (Allen et al., 2016) placed knowledge workers in a controlled environment and measured decision-making performance at 550, 945 and 1,400 ppm. The results:
- 15% drop at 945 ppm — the level a full meeting room reaches in 30 minutes.
- 50% drop at 1,400 ppm — the level your classroom, your boardroom, and your co-working hot desk reach routinely.
The mechanism is still debated — likely a combination of direct CO₂ narcosis at higher concentrations and a correlated drop in ventilation-linked pollutants. The fix is the same either way: move fresh air in.
Three things you can do this week
- Place a monitor in the room where the most important conversations happen. A dashboard is worth a thousand policies.
- Pre-vent. Open windows or ramp ventilation five minutes before meetings start, not five minutes after.
- Cap meetings at 45 minutes. CO₂ in a packed room reliably crosses 1,200 ppm on the hour.
CO₂ is invisible, and invisible things get ignored. Envora makes it visible.