Evaluation on the Potential of 18 Species of Indoor Plants to Reduce Particulate Matter

Background and objective: The main objective of this study is to measure the amount of particulate matter (PM) reduction under different characteristics of leaves in 18 different species of indoor plants. Methods: First, a particular amount of PM was added to the glass chambers (0.9×0.86×1.3 m) containing the indoor plant (height = 40 ± 20 ㎝), and the PM concentration were measured at 2-hour intervals. The experiment with the same conditions was conducted in the empty chamber as the control plot. Results: The range of PM reduction per unit leaf area of 18 species of experimental plants was 3.3-286.2 ㎍·m⁻² leaf, total leaf area was 1,123-4,270 ㎠, and leaf thickness was 0.14-0.80 ㎜ and leaf size 2.27-234.47 ㎠. As time passed, the concentration of PM decreased more in the chamber with plants than in the empty chamber. Among the 18 indoor plants, the ones with the greatest reduction in PM2.5 in 2 hours and 4 hours of exposure to PM2.5 were Pachira aquatica and Dieffenbachia amoena. As the exposure time of PM increased, the efficiency of reducing PM2.5 was higher in plants with medium-sized leaves than plants with large or small leaves. The effect of reducing PM2.5 was higher in linear leaves than round or lobed leaves. Plants with high total leaf area did not have advantage in reducing PM because the leaves were relatively small and there were many overlapping parts between leaves. In the correlation between leaf characteristics and PM 2.5 reductions, all leaf area and leaf thickness showed a negative and leaf size showed a positive correlation with PM reduction. Conclusion: The PM reduction effect of plants with medium-sized leaves and long linear leaves was relatively high. Moreover, plants with a large total leaf area without overlapping leaves will have advantaged in reducing PM. Plants are effective in reducing PM, and leaf characteristics are an important factor that affects PM reduction.