42 research outputs found
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Can houseplants improve indoor air quality by removing CO2 and increasing relative humidity?
High indoor CO2 concentrations and low relative humidity (RH) create an array of well-documented human health issues. Therefore, assessing houseplantsâ potential as a low-cost approach to CO2 removal and increasing RH is important.
We investigated how environmental factors such as âdryâ ( 0.30 m3 m-3) growing substrates, and indoor light levels (âlowâ 10 ”mol m-2 s-1, âhighâ 50 ”mol m-2 s-1 and âvery highâ 300 ”mol m-2 s-1), influence the plantsâ net CO2 assimilation (âAâ) and water-vapour loss. Seven common houseplant taxa â representing a variety of leaf types, metabolisms and sizes â were studied for their ability to assimilate CO2 across a range of indoor light levels. Additionally, to assess the plantsâ potential contribution to RH increase, the plantsâ evapo-transpiration (ET) was measured.
At typical âlowâ indoor light levels âAâ rates were generally low (< 3.9 mg hr-1). Differences between âdryâ and âwetâ plants at typical indoor light levels were negligible in terms of room-level impact. Light compensation points (i.e. light levels at which plants have positive âAâ) were in the typical indoor light range (1-50 ”mol m-2 s-1) only for two studied Spathiphyllum wallisii cultivars and Hedera helix; these plants would thus provide the best CO2 removal indoors. Additionally, increasing indoor light levels to 300 ”mol m-2 s-1 would, in most species, significantly increase their potential to assimilate CO2. Species which assimilated the most CO2 also contributed most to increasing RH
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Interaction between plant species and substrate type in the removal of CO2 indoors
Elevated indoor concentrations of carbon dioxide [CO2] cause health issues, increase workplace absenteeism and reduce cognitive performance. Plants can be part of the solution, reducing indoor [CO2] and acting as a low-cost supplement to building ventilation systems.
Our earlier work on a selection of structurally and functionally different indoor plants identified a range of leaf-level CO2 removal rates, when plants were grown in one type of substrate. The work presented here brings the research much closer to real indoor environments by investigating CO2 removal at a whole-plant level and in different substrates. Specifically, we measured how the change of growing substrate affects plantsâ capacity to reduce CO2 concentrations. Spathiphyllum wallisii 'Verdi', Dracaena fragrans 'Golden Coast' and Hedera helix, representing a range of leaf types and sizes and potted in two different substrates, were tested. Potted plants were studied in a 0.15 m3 chamber under âvery highâ (22000 lux), âlowâ (~ 500 lux) and ânoâ light (0 lux) in âwetâ (> 30 %) and âdryâ (< 20 %) substrate.
At ânoâ and âlowâ indoor light, houseplants increased the CO2 concentration in both substrates; respiration rates, however, were deemed negligible in terms of the contribution to a room-level concentration, as they added ~ 0.6% of a humanâs contribution. In âvery highâ light D. fragrans, in substrate 2, showed potential to reduce [CO2] to a near-ambient (600 ppm) concentration in a shorter timeframe (12 hrs, e.g. overnight) and S. wallisii over a longer period (36 hrs, e.g. weekend)