透空式高層建築對都市街谷中汙染物擴散之影響

The Impact of High-Rise Opening Building Pollutant Dispersion in Urban Street Canyon

人口過度集中於都市衍生出高密度高層建築的居住環境。高密度高層建築群阻礙都市風環境流通，導致部分街廓因遮蔽效應而產生弱風區域，加劇熱島效應，甚至使空氣中的污染物堆積。相關研究指出通風廊道可以帶給都市良好的透氣效果並改善空氣品質及增進熱舒適性，能有效減緩熱島效應。近年來透空式高層建築興起。這些建築透空開口主要功能在減少表面風壓、彎矩等結構考量，有的則是為了豐富多樣造型、風力發電與空中花園等。目前對於透空式高層建築的研究，主要探討建築結構、表面風壓所造成之影響，尚缺乏透空式建築對風、溫度及汙染物影響之研究。本研究以高密度高層建築之概念城市為研究對象，分析透空式高密度高層建築對微氣候影響，以CFD Fluent v18進行模擬，探討不同開口率（13.5％、9％及4.5％）及開口高度（68m、36m）對都市風、溫度及汙染物濃度影響。研究結果顯示，透空式高層建築能增加空氣流通性，改善原有背風面都市風場弱風之情形，也能有效降低街谷中溫度及汙ａ染物濃度，但隨距離增加改善效果會有遞減情形。開口率方面，13.5％開口率相較於其他方案更能增加空氣在街谷中的流動性並降低街谷中的溫度及汙染物濃度；開口高度位在36m（0.45h）時，對於街谷間空氣流動、溫度降溫能及去除汙染物能力有較佳效果。

Overpopulation increases the urban temperature and causes Urban Heat Island Effect. High-density and High-rise buildings bring about an obstacle to the urban environment and not only prone produce strong wind or hinder, but reduce air convection even cause pollutant accumulation. Some of research indicate that ventilation corridors can make city getting good ventilation and improving the air quality. In recent years, the rise of the high-rise opening buildings. These openings are mainly used to reduce surface wind and others are for wind power generation or sky gardens. The research on high-rise opening buildings still lacks of micro-climate influence. The result shows that high-rise opening buildings can improve the weak wind, temperature and pollutant problem in the street canyon, and the 13.5% opening size can increase more flow of air, lower the temperature and lower pollutant concentration than other size in street canyon. Especially when the opening height at 36m (0.45h), can effectively increase the air flow, lower the temperature and have good capacity of removing pollutant in the street canyon.