The Efficiency of Vertical Plants’ Types and Catchment Areas for Absorbing Carbon Dioxide in Ambient Air

Abstract

The Indonesian government has set regulation, whereby 30% of the city region should be repurposed as green open spaces to mitigate climate change. However, several cities have not attained this because of a lack of land availability. One of the potential solutions is using of vertical gardens that can absorb CO2 in limited areas. The study aims to determine the CO2 absorption by several vertical plants at different sizes of planting areas and elevations. The study was conducted on three sites in the Department of Environmental Engineering Institut Teknologi Sepuluh Nopember under various circumstances. The study variables included: (i) plant species, i.e. Antigonon leptopus, Epipremnum aureum, and Vernonia elliptica, which were grown in a 55×40×37cm box reactor, (ii) different catchment or planting areas (25%, 50%, and 75% of the reactor’s surface area), as well as (iii) elevations (0 m, 4.5 m, and 8.5 m above ground level). A single reactor was used as control variable. The parameters under observation were CO2 level, temperature, and light intensity recorded hourly from 06.00 a.m. to 06.00 p.m. The capability of the plant to absorb determined by the difference of Net-CO2-Con. The result shows that the more plant’s catchment areas positively contribute to the reduced CO2. The 75% of Antigonon leptopus potentially decreased by 314 ppmCO2/day, while 50% and 25% of it only decreased by 271 ppmCO2/day and 119 ppmCO2/day. Antigonon leptopus is the most efficient plant in its light tolerance, compared to other plants. Antigonon leptopus showed the highest CO2 uptake value at 314 ppmCO2/day, while Epipremnum aureum and Vernonia elliptica displayed 126 ppmCO2/day and 184 ppmCO2/day respectively. However, the CO2 uptake capability of each plant at different elevations was subjected to bias due to coverage by buildings and canopies. This altered the intensity of sunlight and interfered with plant assimilation, ultimately impacted the uptake capability of CO2.