Potted-plant presence was associated
with significant reductions in both CO2 and CO concentrations
(Table below). CO2 levels in planted offices were reduced by
about 10% in the air-conditioned building, and by about 25%
in the building without air-conditioning. CO concentrations were
very greatly reduced with plant presence, down to 8-14% of
those in unplanted offices, with or without air-conditioning.