季節與風向對綠牆淨化空氣之影響

Effects of Season and Wind Direction on Air Purification of Green Wall

李宜軒(Yee-Hsian Li)

指導教授 ： 葉德銘

國立臺灣大學/生物資源暨農學院/園藝暨景觀學系/碩士(2021年)

https://doi.org/10.6342/NTU202103810

摘要

在已開發國家中最常見的室內汙染物為甲醛、二氧化碳 (carbon dioxide, CO2)與懸浮微粒 (particulate matter, PM)。前人研究指出植物能減少室內甲醛、CO2和PM，但在空間有限的室內難以放入達顯著淨化室內空氣效果所需的植物數量。綠牆能在小範圍的空間內提高植栽的密度，而主動式綠牆設有風扇能夠強制抽風，迫使汙染物通過綠牆，進而提高淨化空氣效率，因此可彌補植栽密度不足問題的綠牆與主動式綠牆(active living wall, ALW)模組便成為本次試驗的重點。針對綠牆系統進行以下三個試驗。
在臺大園藝分場架設四面在不同季節承受不同受風面之綠牆，並裝設風向計與環境PM2.5偵測器以探討風向對綠牆捕捉PM2.5之影響。每月於每月於每面綠牆取一次Nephrolepis exaltata與 Philodendron ‘Xanadu’ 之剛完全展開葉，並利用掃描式顯微鏡 (Scanning electronic microscope, SEM) 調查風向與環境PM2.5濃度是否影響葉片捕捉PM能力。結果顯示背風面之綠牆環境PM2.5濃度最高，同時SEM調查也指出此牆面之葉片亦捕捉相對比較高量的PM。晚春至夏季的的風向較偏東南風，而晚秋至春天的風向則較偏東北，因此不同季節之風面影響的綠牆牆面也不同。
在楠梓國小教室前後走廊外設置兩面懸垂式綠牆，並在綠牆的前方、後方、後方教室內以及隔壁無綠牆之對照組教室內裝設空氣品質偵測器來探討戶外綠牆是否能降低室內CO2、PM2.5、 PM10以及O3之濃度。試驗結果指出在綠牆後的教室相較於對照組之教室，除了PM10以外的汙染物的濃度都較低。除此之外，設有綠牆之教室在夏天的溫度會比對照組的教室低，而冬天與春天時會比對照組的教室高，進而提供較為舒適的室內環境。
將設有風速0.6 m·s-1風扇之2019 年新式主動式綠牆模組(active living wall modules, ALW modules) (長 56 cm ×寬 48 cm × 高72 cm)，分別搭配四盆N. exaltata或四盆P. oxycardium ，結果指出N. exaltata 在PM10之移除率上與P. oxycardium 無明顯差異，分別為98.6% 與 99%，但在甲醛移除率上差距比較大，分別為81.3% 與 77.3%。。
將2019 ALW modules 、2018 ALW module (長 57 cm ×寬 22 cm × 高67 cm) 與市售空氣清淨機分別置入燃燒線香之密閉薰氣箱，測試三小時後顯示2019 ALW module比2018 ALW module與參試空氣清淨機移除更多甲醛，分別為 77.3%-81.3% 、62.9% 與 40.4%)。2019 ALW module之PM10移除率較2018 ALW module高，比參試空氣清淨機來的低 ，分別為98.6%-99% 、 89.9% 與 100% ，但差距不大。

關鍵字

主動式綠牆 ； 二氧化碳 ； 甲醛 ； 綠牆 ； 懸浮微粒

並列摘要

The most common indoor air pollutants in developed countries are formaldehyde, carbon dioxide, and particulate matter (PM). Literature research indicate Potted plants can remove various pollutants indoors but are impractical due to the large numbers of potted plants needed to achieve significant pollutant removal in an environment that is usually constrained by space. Botanical filters such as green walls and active living walls (ALW) modules can remedy this problem by providing a higher foliage density and a mechanical system that draws in ambient air, forcing the pollutants to go through the green wall. This is the why 3 experiments were conducted on green wall systems.
Four outdoor green walls each facing a different direction were set up in NTU farm. Ambient PM2.5 sensors and wind direction detectors were installed to analyze the relationship between wind direction, ambient PM2.5 concentration and green wall PM interception rate. Each month the just fully opened leaves of Nephrolepis exaltata and Philodendron ‘Xanadu’ were harvested, and micrographs were taken using a scanning electron microscope (SEM) to determine whether wind directions and ambient PM influence the PM interception rate of the green wall. Results indicate the leeward side of the green wall had a higher ambient PM2.5 concentration, and SEM results also indicate that the leeward green wall had a higher PM capture rate. Seasonal winds were also observed in the NTU farm, where the wind directions during late spring to summer are focused on southeast winds, while late autumn to spring wind directions are mainly focused on the northeast side. Therefore, the changing of season also has an effect on the green wall.

Two vine type green walls set up on the outside of the classroom of Nanzi elementary school, and sensors were set up in front of the green wall, behind the green wall, in the classroom behind the green wall and the control group classroom that’s not behind any green walls. This would allow the determination of whether outdoor green walls can reduce indoor CO2, PM2.5, PM10, formaldehyde and O3 concentrations. Experiment results indicate the classroom behind the green wall has a lower ambient concentration of pollutants other than PM10. In addition to the benefits mentioned, the relative humidity in the classroom behind green walls is also higher. The temperature in the classroom behind green walls is also lower than the control group during summer, and higher during winter and spring, thereby providing a more comfortable environment. in.
ALW modules with fans that run at 0.6 m·s-1 (56 cm × 48 cm × 72 cm) was paired with 4 Nephrolepis exaltata or 4 Philodendron oxycardium. The results show that the Nephrolepis exaltata PM10 removal rate is not significantly higher than Philodendron oxycardium, which are 98.6% and 99%. However, the difference in formaldehyde removal rate is higher, 81.3% and 77.3%.
When placing the 2019 active living wall module (ALW modules), 2018 modules (57 cm × 22 cm × 67 cm) and the conventional air purifier into the acrylic chamber with incense used as the pollution source, the removal rate of formaldehyde after 3 hours for the 2019 ALW module is higher than 2019 ALW module, but lower than the conventional air purifier, which are 77.3%-81.3%, 62.9% and 40.4%. The PM10 removal rate for the 2019 ALW module is higher than the 2018 ALW module, but lower than the conventional air purifier, which are 98.6%-99%, 89.9% and 100%, but the difference is not significant.

並列關鍵字

Active living walls ； carbon dioxide ； formaldehyde ； green walls ； particulate matter

參考文獻

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