| Indoor low concentrations of CO,formaldehyde and particulate matter are hazardous to human health in the long term,and the scientific basis for potted plants as a popular means of air purification has yet to be further explored.In this thesis,four potted plants,namely,Scindapsus aureus,Chlorophytum comosum,Spathiphyllum floribundum,Sansevieria trifasciata,were used to investigate the purification ability of CO and formaldehyde at initial CO concentrations of 10,25,50,100,200 and 400 ppm,and at initial formaldehyde concentrations of 0.5,1.0 and 2.0 mg/m~3.In addition to these four potted plants,a total of eight potted plants,including Peperomia tetraphylla,Anthurium andraeanum,Monstera deliciosa,Ficus elastica,were used to investigate their adsorption capacity for indoor particulate matter.The main findings of this thesis are as follows:1)The purification ability of the four potted plants for CO was ranked as follows:Scindapsus aureus>Chlorophytum comosum>Spathiphyllum floribundum>Sansevieria trifasciata.Each plant was able to reduce the CO concentration to below the concentration exposure limit specified by some countries and organizations within a certain period of time.The CO purification rate of the four green plants decreased exponentially with the increase of CO concentration,and the purification rate of the green plant was as high as 96%at the initial CO concentration of 10 ppm within 48 h.The hourly CO uptake of each green plant increased linearly with the increase of CO concentration.There was a significant positive correlation between the number of stomata and leaf area and cumulative CO uptake.After the 48-h experiment with initial CO concentration≥100 ppm,the leaf tips of Scindapsus aureus and Chlorophytum comosum were successively damaged within a week,and the damaged leaf area increased with the increase of CO concentration.2)The purification ability of the four potted plants for formaldehyde was ranked as follows:Scindapsus aureus>Spathiphyllum floribundum>Chlorophytum comosum>Sansevieria trifasciata.The tested plants were able to reduce the concentration of formaldehyde to below the concentration exposure limit specified by some countries and organizations within a certain period of time.The purification rate of formaldehyde by the four green plants decreased with the increase of formaldehyde concentration,and the purification rate of the four green plants could reach 100%when the initial concentration of formaldehyde was 0.5 mg/m~3 within 48 h.The formaldehyde absorbed by each potted green plant per hour increased linearly with the increase of formaldehyde concentration.There was a significant positive correlation between the number of stomata and leaf area and the cumulative formaldehyde absorption.Within one week after the 48-h experiment with initial formaldehyde concentration≤2.0 mg/m~3,the leaves of Scindapsus aureus,Chlorophytum comosum and Spathiphyllum floribundum were successively damaged,with the greenery having the largest damaged area,and the damaged leaf area increased with the increase of formaldehyde concentration,but each plant as a whole still survived.3)The adsorption of particulate matter per unit leaf area was from high to low:Ficus elastica>Peperomia tetraphylla>Monstera deliciosa>Anthurium andraeanum>Spathiphyllum floribundum>Scindapsus aureus>Chlorophytum comosum>Sansevieria trifasciata,and the highest adsorption of particulate matter per unit leaf area was 1.126 mg/cm~2 in 3 weeks.The highest total particulate matter adsorption(nearly2900 mg)over the 3-week period was found in the Monstera deliciosa and Scindapsus aureus,and the lowest was found in the Sansevieria trifasciata and Anthurium andraeanum.The adsorption of particulate matter per unit leaf area increased with increasing stomatal density and increased with decreasing stomatal length,leaf long-axis and leaf long-short axis ratio.The total particulate matter adsorption increased with the increase of total stomatal number,total leaf area,plant height and plant crown width.The frequency of single particle size distribution of particulate matter adsorbed on the leaf surface of the eight green plants showed a single-peaked distribution with peaks concentrated at 1～4μm.Particulate matter was mainly deposited in the grooves between folds and folds,and the larger the groove space,the larger the particle size of deposited particulate matter.Fine particles are deposited around or above the stomata and can enter the inside of the stomata when the stomata are opened.There are 47 figures,22 tables and 151 references in this thesis. |
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