Quantification of Carbon Assimilation of Indoor Plants in Simulated and In Situ Interiorscapes

Quantification of Carbon Assimilation of Indoor Plants in Simulated and In Situ Interiorscapes

Article Reference: Green Plants for Green Buildings
Source: Svoboda V. Pennisi and Marc W. van Iersel




Abstract
Interiorscape plants have many documented benefits, but their potential for carbon sequestration is not clear. This study was undertaken to quantify the amount of carbon assimilation under growth chamber conditions designed to mimic the photosynthetic photon flux (PPF) levels and temperatures of typical indoor environments and to quantify the amount of carbon assimilation in situ in a representative interiorscape composed of a variety of indoor plant species and sizes.

Quantitative data were obtained in 1) growth chambers for interiorscape plants with a typical range of PPF levels encountered indoors; and 2) in situ conditions in an interiorscape environment. Under growth chamber conditions, most species exhibited positive dry mass accumulation and carbon sequestration but Sanseveria and Dracaena "Janet Craig" exhibited consistent dry mass loss throughout the ten weeks under simulated conditions in the interiorscape environment. Carbon content was lower in herbaceous species (e.g., Scindapsus aureus, 38% of dry mass) compared with woody ones (e.g., Ficus benjamina, 43%). PPF-saturated net photosynthetic rates of plants were low. In situ, indoor plants exhibited varying dry mass gain, largely dependent on size. In general, a large interiorscape plant and/or indoor plant species with a higher amount of woody tissue in their above- or below ground organs (e.g., 4.6 m high arboreal plant) sequestered more carbon than small and/or herbaceous species.

This study is the first to provide quantitative data of carbon sequestration in interiorscape environments.

Conclusions
Carbon fixation in an interiorscape environment was dominated by a few large interior plants. Over time larger interior lants (which are generally woody species) accumulated significantly larger quantities of dry mass (and carbon) compared with smaller, herbaceous species of interior plants. Although positive carbon gains were demonstrated both under simulated and in situ conditions, the reduction in ambient carbon dioxide levels by interiorscape plants is not likely to substantiate claims for a significant impact on indoor air quality.

Interiorscape plants have been documented to remove volatile organic compounds (VOCs), and it is this aspect that should serve as a basis for the claim for improvement of indoor air quality. Carbon dioxide assimilation provides corollary information to the VOC removal and a more complete assessment of plants’ benefits to the interiorscape environment.