Monitoring of air quality and indoor environment in rooms occupied by houseplants

The present paper describes an experimental test to identify the possible influences that the presence of plant species may have on the environmental quality of indoor spaces. For this purpose, a selection of houseplants with high air purification capacities was made based on existing literature (Sansevieria, Poto, Spathiphyllum, Ficus Benjamina, Kentia and Areca). Two adjacent rooms within an experimental building were used as test cells. The two rooms have similar characteristics. One room was occupied with the plants and the other was left empty. The test was conducted without human presence, except for maintenance tasks. Indoor environmental quality variables (T, RH and CO2) were recorded every 10 minutes during the whole period of the experiment. In addition, spot measurements of formaldehyde and volatile organic compounds were also included. From the analysis of the results recorded by the sensors it is concluded that the presence of houseplants can reduce the concentration of VOCs. The conclusions are less clear for the CO2 measurements, due to the uncertainties identified. Nevertheless, it was detected that factors such as plant density, irrigation, ventilation, sun exposure and the type of substrate and specimen, influenced the test. The results such as the increase in CO2 when placing a high number of plants with organic substrate or the good performance of most species to reduce this pollutant, allow the design of a new detailed experiment with specific conditions on the number and type of plants, the type of substrate and the possibility of introducing pollutants in a controlled way.