Gas Exchange Research on Plant Layers of Green Structures and Indoor Greening for Sustainable Construction

Green structures, buildings incorporating living plants, offer numerous benefits, including carbon sequestration and improved indoor air quality. (1) However, the effective design and analysis of these structures are hindered by a lack of standardised methodologies. This work proposes a novel four-zone method for instantaneous gas exchange testing in green structures. (2) The method involves estimating gas exchange by measuring gas content at the plant zone’s entrance and exit, with individual CO2 content measurements within the zone to account for inertia and stratification effects exacerbated by mixing. (3) This method has been adopted into a national standard draft. The dependency of CO2 absorption/release is obtained for Chlorophytum comosum. The method is also successfully tested on Ligustrum vulgare. (4) The developed method provides formulas and data on CO2 absorption/release for use in designing green structures and indoor greening systems. Results show that Chlorophytum comosum can consume over 23 μg/s of CO2 per square meter of foliage, with a light saturation threshold for CO2 absorption between 8500 and 20,000 phlx, depending on CO2 levels.