Meeting rooms and CO₂

The single most-asked-about office IAQ problem is the conference room everyone hates. The shape is consistent: a closed room, dense occupancy, an HVAC system designed for occasional use, and a one-hour meeting that ends with everyone yawning. The CO₂ math is unforgiving: eight adults emit roughly 130 liters of CO₂ per hour collectively, which a typical 50 m³ meeting room absorbs into a sealed envelope as roughly 1,500 ppm of accumulation per hour.

ASHRAE 62.1 targets a per-occupant fresh-air rate that keeps even a packed room under 1,100 ppm. Most commercial HVAC systems are sized to that floor, but the actual delivery depends on whether the system runs (occupancy schedules, dampers, and economizer settings all interact), whether the building's ventilation control accounts for actual occupancy, and whether the diffusers are clean.

The cognitive cost is documented. Allen et al. at Harvard's Healthy Buildings program ran controlled exposures and found decision-making performance dropped 15% at 1,400 ppm vs 600 ppm, with the largest decrements in strategic thinking and information utilization. Satish et al. at LBNL ran a separate cohort and saw similar effects. The implication: high-stakes decisions made at the end of a long meeting in a closed room are demonstrably worse decisions.

For facility managers, the response is demand-controlled ventilation driven by CO₂ sensors in each room. For individuals, the response is to crack the door (single largest intervention), take 5-minute breaks every 45 minutes (lets the room recover partially), or book larger rooms than headcount strictly requires. The dashboard, deployed in a meeting room, will tell you which of your rooms are routinely starving for air; usually it's the ones everyone avoids.