室內植物移除二氧化碳能力之研究

Abstract

隨著人們生活水準的提高，室內裝飾材料不斷翻新，導致辦公大樓和住宅內空氣污染物質增加，威脅人類的健康。二氧化碳(Carbon dioxide, CO2)已被臺灣列為室內空氣污染物質，為室內空氣品質之指標，因此必須維持室內場所之CO2在一定濃度以下，雖然許多研究指出植物具有空氣淨化能力，但利用植物於室內移除CO2之相關資料並不完整，因此本研究將四十種室內植物置於1200 ± 50 μL･L-1之密閉熏氣箱(0.128 m3)中測定其CO2移除能力之差異，進而探討植物於不同光強度、光質、光度馴化及生長調節劑處理，並模擬夜間黑暗環境與長時間於高CO2環境下，對室內植物CO2移除能力之影響。 室內植物之CO2移除能力方面，將四十種室內植物置於光強度80 μmol･m-2･s-1和CO2初始濃度1200 μL･L-1之密閉熏氣箱中，測定0800 HR至1700 HR其CO2移除能力之表現，探討不同室內植物對CO2移除能力之差異。研究結果顯示：所有參試植物種類於高CO2濃度與明亮環境下皆具有CO2移除能力，且多數參試植物於試驗開始至第1小時，有最大的單盆與單位葉面積CO2移除能力；植物之總葉面積多寡與單盆CO2移除能力具顯著相關性(R2=0.58)，如波斯頓腎蕨(Nephrolepis exaltata ‘Bostoniensis’)、白鶴芋‘帕拉斯’ (Spathiphyllum floribundum ‘Palas’)及臺灣山蘇(Asplenium nidus)等總葉面積較高者有較高的單盆CO2移除能力。利用單盆、單位葉面積及T50%之CO2移除能力三種方式進行綜合評估，大岩桐(Sinningia speciosa)、黑葉觀音蓮(Alocasia ×amazonica)、聖誕紅‘倍利’ (Euphorbia pulcherrima ‘Pepride’)等，具有較高的CO2移除能力。 室內植物淨化空氣之效果易受到各環境因子影響，其中光線變化影響甚大，因此本研究主要探討光線對室內植物CO2移除能力之影響。大岩桐、黃金葛(Epipremnum aureum)及合果芋‘綠精靈’ (Syngonium podophyllum Schott ‘Pixie’)，上述三者之單盆CO2移除能力分別為1203 ± 56 μL･L-1、604 ± 49 μL･L-1及 336 ± 45 μL･L-1，因此將三種室內植物列為CO2移除能力之高、中、低的代表，並進行相關試驗。光強度方面，隨著光強度由5 μmol･m-2･s-1增加至80 μmol･m-2･s-1，大岩桐、黃金葛及合果芋‘綠精靈’CO2移除能力皆提升，但光度為5 μmol･m-2･s-1時，黃金葛與大岩桐單盆CO2移除能力分別為-2.3 μL･L-1與-4.0 μL･L-1，並由三種室內植物之光曲線試驗中結果顯示光補償點可作為評估室內植物維持CO2移除能力之最低光強度標準，而光飽和點則可視為最高光強度標準。在光質方面，光強度40 μmol･m-2･s-1下，以白光、紅光、藍光、紅光/藍光比例為R84/B16、R57/B43及R12/B88之6種不同光質處理，結果以R84/B16光質比例下，大岩桐、黃金葛及合果芋‘綠精靈’均有最佳移除效果。光馴化試驗方面，以臺灣山蘇(Asplenium nidus)於未馴化、光強度100 μmol･m-2･s-1及200 μmol･m-2･s-1下馴化45天後，於40 μmol･m-2･s-1下測定其CO2移除能力，三者之間並無顯著差異，但未馴化者之淨光合作用速率最高，而100 μmol･m-2･s-1馴化者比200 μmol･m-2･s-1馴化者有較高淨光合作用速率。 在生長調節劑試驗方面，先將參試植物置於光強度40 μmol･m-2･s-1下，分別施噴去離子水(對照組)與1、5、10 μM Kinetin (N6-Furfuryladenine)及 1、5、10 μM IBA (indole-3-butyric acid, IBA)，測量其前後氣孔導度之差異，以進行後續試驗，研究顯示：在試驗第1小時，5 μM IBA處理之熏氣箱中CO2濃度下降得比對照組快，但於0900 HR後無顯著差異，而合果芋‘綠精靈於試驗開始2小時，5 μM Kinetin處理之熏氣箱中CO2濃度下降得比對照組快，但於1000 HR後無差異。大岩桐噴施5 μM IBA之單盆CO2移除能力與對照組並無顯著差異，而合果芋‘綠精靈’噴施5 μM Kinetin之單盆CO2移除能力與對照組也有相似的結果。因此5 μM IBA與5 μM Kinetin可使植物氣孔導度增加並提升初始CO2吸收速率，但對植物單盆CO2移除量影響不大。 在黑暗環境12個小時之下，大岩桐、黃金葛、合果芋‘綠精靈’及臺灣山蘇四種植物單盆CO2釋放量並無顯著差異，平均僅釋放188.9 μL･L-1。在連續7天於高CO2環境和40 μmol･m-2･s-1光強度下，大岩桐與黃金葛兩種植物夜間雖然釋放CO2，但植物於白天確實能持續吸收CO2，達到長時間移除效果，而隨著時間增加，參試植物之CO2移除能力逐漸下降，在24小時內平均可移除熏氣箱中約60 %之CO2。

As our standard of living improved, our indoor living environment has become more sophisticated. However, this has also increased the level of air pollutants inside our living and working spaces, which can affect our health adversely. Carbon dioxide (CO2) is classed as an indoor air pollutant in Taiwan and CO2 concentration is often used as an indicator of indoor air quality. Therefore, indoor CO2 concentration should be maintained below a certain level. While much research work has shown that indoor plants have the ability to purify the indoor air, the study of CO2 removal capability of indoor plants is largely incomplete. In this study, forty indoor plant species were exposed to CO2 (1200 ± 50 μL･L-1) in airtight chambers (0.128 m3) to determine their ability to remove CO2. How the amount of CO2 removed was affected by light intensity, light quality, light acclimation, plant growth regulators, dark condition and long term exposure to high concentration of CO2 exposure was also assessed. Forty indoor plant species were tested to determine their ability to remove CO2 under a condition typically found indoors. The plants were exposed to an initial CO2 concentration of 1200 μL･L-1 in fumigation chambers with 80 μmol･m-2･s-1 light intensity to determine CO2 removal from 0800 HR to 1700 HR. The results show that all 40 indoor plants can remove CO2 under high CO2 concentration and bright light. Most plants had highest CO2 removal rate of single whole plant and unit leaf area of the plants, during the first hour of exposure. There was significant correlation between total leaf area of the plant and CO2 removal ability of single whole plant (R2=0.58); plants having higher total leaf area such as Nephrolepis exaltata ‘Bostoniensis’, Spathiphyllum floribundum ‘Palas’, and Asplenium nidus. had higher CO2 removal ability per whole plant. Sinningia speciosa, Alocasia ×amazonica, and Euphorbia pulcherrima ‘Pepride’ were plant with high CO2 removal ability based on evaluations with CO2 removal per whole plant, per unit area and T50%. The ability of indoor plants to purify air is affected by environmental factors, among which light plays a very important role. The effect of light on CO2 removal by indoor plants was investigated in this study. The CO2 removal abilities of Sinningia speciosa, Epipremnum aureum, and Syngonium podophyllum Schott ‘Pixie’ were 1203 ± 56 μL･L-1, 604 ± 49 μL･L-1, and 336 ± 45 μL･L-1 respectively. They were chosen to represent indoor plants having high, intermediate, and low CO2 removal ability respectively in the following investigations. On the aspect of light intensity, the CO2 removal ability of Epipremnum aureum and Syngonium podophyllum Schott ‘Pixie’ was improved as light intensity increased from 5 μmol･m-2･s-1 to 80 μmol･m-2･s-1. The CO2 removal ability of Epipremnum aureum was -2.3 μL･L-1 and that of Syngonium podophyllum Schott ‘Pixie’ was -4.0 μL･L-1 under 5 μmol･m-2･s-1 PPF. From the light curves of the three indoor plants, light compensation point can be used to estimate the standard for the minimum light intensity required for CO2 removal by indoor plants, and the light saturation point can be regarded as the standard for highest light intensity. In another experiment investigating the effect of light quality under 40 μmol･m-2･s-1 intensity, plants were subjected with 6 different light treatments: white light, red light, blue light, and red:blue light ratios of 84:16 (R84/B16), 57:43 (R57/B43), and 12:88 (R12/B88). CO2 absorption by Syngonium podophyllum ‘Pixie’, Scindapsus aureum, and Sinningia speciosa was optimal under a red:blue ratio of 84:16. On the aspect of light acclimation, Asplenium nidus plants were given no acclimation or acclimated under 100 μmol･m-2･s-1 or 200 μmol･m-2･s-1 light intensity for 45 days before determining CO2 removal at 40 μmol･m-2･s-1 intensity. There was no significant difference in CO2 removal ability among treatments, but plants given no acclimation had the highest net photosynthesis rate, whereas those acclimated at 100 μmol･m-2･s-1 had higher net photosynthesis rate than those acclimated at 200 μmol･m-2･s-1. On the aspect of plant growth regulator, plants were put under 40 μmol･m-2･s-1 light intensity and were sprayed with deionized water (control), 1, 5, or 10 μM kinetin (N6-furfuryladenine) and 1, 5, or 10 μM IBA (indole-3-butyric acid, IBA), and stomatal conductance was measured before and after spraying. The results show that plants sprayed with 5 μM IBA reduced the CO2 concentration in the chamber faster 1 h after treatment compared with control, but there was no significant difference between treatments after 0900 HR. At 2 hr after treatment, Syngonium podophyllum Schott ‘Pixie’ sprayed with 5 μM Kinetin reduced the CO2 concentration in the chamber faster compared with control, but there was no significant difference between treatments after 1000 HR. Sinningia speciosa showed no significant difference in CO2 removal ability per pot between control and 5 μM IBA treatment and similar result was obtained between Syngonium podophyllum Schott ‘Pixie’ sprayed with 5 μM Kinetin or control. Therefore, spraying with 5 μM IBA and Kinetin increased stomatal conductance and improved the initial CO2 uptake rate, but had no effect on CO2 removal ability per pot. There was no significant difference in CO2 emission per pot between Sinningia speciosa, Epipremnum aureum, Syngonium podophyllum Schott ‘Pixie’ and Asplenium nidus under 12 hours in a dark environment, whereby the average release was 188.9 μL･L-1 CO2. Under high CO2 concentration and 40 μmol･m-2･s-1 light for seven days, Sinningia speciosa and Epipremnum aureum released CO2 at night, but CO2 was removed during the day. As time increased, the ability of the tested plants to remove CO2 decreased; about 60% of the CO2 in chambers could be removed within 24 hours.