On Influence of Plants on the Quality of Indoor Environment from the Point of View of Building’s Operation and Ventilation
Authors:   , Franek Ondřej 
Published: May 2024

The present paper deals with unique research on the effect of plants on the quality of the indoor building’s environment with a positive impact on operational savings in building ventilation aspects. The present paper contains a number of theoretical simulations and unique verifying of practical measurements that are necessary for understanding the issue of implementing plants into the internal environment of buildings and their operation. Theoretical simulations deal with variable parameters of the required quality of the indoor environment Creq and the quality of the supplied air Csup from the point of view of CO2 and VOC (Volatile Organic Compounds) with variable lighting. Based on the provided calculation, it was shown that for a sample office indoor environment with a volume of 74.7 m3, occupancy of 3 people and the implementation of 3 m2 of green leaves, when lighting 40 % green plant leaves PPFD (Photosynthetic Photon Flux Density) = 300 μmol · m-2 · s-1 and 60 % green leaves 80 μmol · m-2 · s-1, brings potential saving of 0.31 % to 1.44 % on building ventilation and PPFD = 100 / 60 μmol · m-2 · s-1 potential savings of 0.15 % to 0.98 %. Using provided theoretical simulations, it was shown that VOC is a minority compared to CO2, but plants can still contribute significantly to reducing its concentration. Using practical measurements, it was found that for plant illumination, it is advisable to place them near openings with direct access to natural light, since in the model office, only artificial lighting used for office lighting showed insufficient illumination values in the PPFD range of 0 to 10 μmol · m-2 · s-1, whereas after sunrise and illumination of the workplaces with natural light, the measured values in the autumn-winter-spring period ranged from 0 to 647 μmol · m-2 · s-1 PPFD. In this thesis, the actual performance of selected cultivars of Ficus Benjamina and Aloe Vera was practically measured in an enclosed model space simulating light conditions and the respective CO2 concentrations of the indoor environment. The measurements of the cultivar Ficus Benjamina (C3 - the most common metabolic pathways for carbon fixation in photosynthesis) significantly exceeded the theoretical assumptions when, with a leaf area of ~ 0.26 m2, and a PPFD light level of ~ 139 μmol · m-2 · s-1 at the upper level of the plant canopy, it was able to reduce the CO2 concentration on average by 0.526 g · m-2 · h-1, and at PPFD ~ 49 μmol · m-2 · s-1 by 0.421 g - m-2 - h-1, whereas the theoretically calculated value at more suitable light conditions of PPFD 300 / 80 μmol · m-2 · s-1 was only 0.307 g · m-2 · h-1 and 0.150 g · m-2 · h-1, respectively, in the case of PPFD 100 / 60 μmol · m-2 · s-1. For the Aloe Vera cultivar (CAM - carbon fixation pathway that evolved in some plants as an adaptation to arid conditions), the values were less favourable as expected, with an average of 0.022 g · m-2 · h-1 assimilated by the plant at PPFD ~ 90 μmol · m-2 · s-1 and 0.005 μmol · m-2 · s-1 at PPFD ~ 50. The last part of the work takes into account the monitoring of the behaviour of employees in a real office environment with the monitoring of the CO2 concentration evolution for one working week, where habits and potential opportunities with an impact on savings in the field of building ventilation can be appropriately identified. Overall, this work confirms the current limited understanding of the issue of plant implementation in the indoor environment of buildings and points to a completely new scientific field that needs to be further developed and researched.