Green wall technology for the phytoremediation of indoor air: a system for the reduction of high CO<inf>2</inf> concentrations

© 2016, Springer Science+Business Media Dordrecht. Along with the growing requirement to reduce building carbon emissions, a need has arisen to find energy efficient means of improving the quality of indoor air. Indoor plants have been shown to be capable of reducing most air pollutants; however, practical numbers of potted plants will not have the capacity to control many forms of air pollution, especially CO2. Green walls are space-efficient means of increasing the density of indoor plants. We assessed an active green wall for its potential to reduce CO2 in chambers and a test room. Chlorophytum comosum and Epipremnum aureum were both effective cultivars for CO2 removal at light densities greater than 50 μmol m−2 s−1. Substrate ventilation increased the rate of CO2 draw down from chambers, possibly due to increased leaf gas exchange rates. Green walls were then tested in a 15.65-m3 sealed simulation room, allowing the calculation of clean air delivery rate (CADR) and air changes per hour (ACH) equivalents based on CO2 draw down. Rates of CO2 draw down were modest under typical brightly lit indoor conditions (50 μmol m−2 s−1); however, when light intensity was increased to relatively bright levels, similar to indoor conditions next to a window or with the addition of supplementary lighting (250 μmol m−2 s−1), a 1-m2 green wall was capable of significant quantifiable reductions of high CO2 concentrations within a sealed room environment. Extrapolating these findings indicates that a 5-m2 green wall containing C. comosum could balance the respiratory emissions of a full-time occupant