Extended Data Fig. 2: Envisioned system for CO2 capture from indoor environments.

Occupancy in buildings often results in higher indoor CO2 concentrations relative to atmospheric CO2 concentrations. Direct air capture (DAC) modules installed in a building’s heating, ventilation, and air conditioning (HVAC) systems take indoor air (red arrow) and output highly-concentrated CO2 as a product gas (beige arrow) while recirculating the purified air back into the building (grey arrow) (Source: authors).