This paper reviews the state of art of vegetation systems and their effect on the indoor environmental quality (IEQ), based on scientific studies from the past 30 years. Some studies have shown that biophilic workspaces and interaction with plants may change human attitudes, behaviours, improve productivity and the overall well-being. Evapotranspiration from plants helps lowering the temperature around the planting environment and this can be utilised for air cooling and humidity control. Also, indoor greenery can be used to reduce sound levels as a passive acoustic insulation system. Living wall systems in combination with biofiltration are emerging technologies to provide beneficial effects on improvement of indoor comfort. Several studies have indicated that green systems may improve indoor air quality and that they have different pathways for pollutant removal of volatile organic compounds. The plant root zone in potted plants may be an effective area for removing volatile organic compounds under controlled conditions. In conclusion, the full capacity of plants in real-life settings will need to be clarified to establish the true pollutant-removal mechanisms and the general effect on IEQ. The effects of green systems in combination with mechanical elements such as conventional heating, ventilation and air conditioning would need to be studied.

Potted plants have been reported to uptake VOCs and help “cleaning” the air. This paper presents the results of a laboratory study in which two species of plants (peace lily and Boston fern) and three kinds of substrates (expanded clay, soil, and activated carbon) were tested and monitored on their capacity to deplete formaldehyde and CO2 in a glass chamber. Formaldehyde and CO2 were selected as indicators to evaluate the biofiltration efficacy of 28 different test conditions; relative humidity (RH) and temperature (T) were monitored during the experiments. To evaluate the efficacy of every test, the clean air delivery rate (CADR) was calculated. Overall, soil had the best performance in removing formaldehyde (~0.07–0.16 m3/h), while plants, in particular, were more effective in reducing CO2 concentrations (peace lily 0.01m3/h) (Boston fern 0.02–0.03 m3/h). On average, plants (~0.03 m3/h) were as effective as dry expanded clay (0.02–0.04 m3/h) in depleting formaldehyde from the chamber. Regarding air-cleaning performance, Boston ferns presented the best performance among the plant species, and the best performing substrate was the soil.

Potted plants have been reported to uptake VOCs and help ‘cleaning’ the air. This paper presents the results of a laboratory study in which two species of plants (Peace Lily and Boston Fern) and three kinds of substrates (expanded clay, soil and activated carbon) were tested and monitored on their capacity to deplete formaldehyde and CO2 in a glass chamber. Formaldehyde and CO2 were selected as indicators to evaluate the bio-filtration efficacy of 28 different test conditions; relative humidity (RH) and temperature (T) were monitored during the experiments. To evaluate the efficacy of every test the Clean Air Delivery Rate (CADR) was calculated. Overall, soil had the best performance in removing formaldehyde (~ 0.07–0.16 m3/h), while plants, in particular, were more effective in reducing CO2 concentrations (Peace lily 0.01m3/h) (Boston fern 0.02-0.03m3/h). On average, plants (~ 0.03 m3/h) were as effective as dry expanded clay (0.02–0.04 m3/h) in depleting formaldehyde from the chamber. Regarding air cleaning performance, Boston ferns presented the best performance among the plant species, and the best performing substrate was the soil.

Active plant-based systems are emerging technologies that aim to improve indoor air quality (IAQ). A person’s olfactory system is able to recognize the perceived odor intensity of various materials relatively well, and in many cases, the nose seems to be a better perceiver of pollutants than some equipment is. The aim of this study was to assess the odor coming out of two different test chambers in the SenseLab, where the participants were asked to evaluate blindly the level of acceptability, intensity, odor recognition, and preference at individual level with their noses. Two chambers were furnished with the same amount of new flooring material, and one of the chambers, Chamber A, also included an active plant-based system. The results showed that in general, the level of odor intensity was lower in Chamber B than in Chamber A, the level of acceptability was lower in Chamber A than in Chamber B, and the participants identified similar sources in both chambers. Finally, the preference was slightly higher for Chamber B over Chamber A. When people do not see the interior details of a room and have to rely on olfactory perception, they prefer a room without plants.

Our sensory system (nose) could predict the perceived odour intensity of various materials relatively well and in many cases the nose seems to be a better receptor of pollutants than some equipment. To test this ability with children, odour tests were performed as part of a study performed with 335 primary school children in the air quality test chamber of the SenseLab. Two similar experiments were conducted to assess the identification of potentially recognizable odours for children. The different sources of odour were placed in different containers and the children were asked how they feel about the smell and to identify the source of smell. There were statistically significant differences among children’s evaluations of different smells and it was difficult for them to identify certain sources of smell.