城市工厂林立,汽车穿梭,空气中含有相当多的尘埃、炭粒、油烟、铅和汞的微粒以及二氧化硫、氟化氢等有害气体,危害着居民的健康。植树、种草、种花,扩大绿色植物的面积,能吐氧吸碳,净化空气,阻滞粉尘等,有益于人的身体健康。由于城市人口聚居,道路密集,楼房占地多,可供绿化的面积相对减少。为了解决这个矛盾,国外多采取楼顶绿化来解决。楼顶绿化就是在各类楼 There are many factories in the city, such as cars and shuttles. The air contains quite a lot of dust, carbon particles, soot, lead and mercury particles, and harmful gases such as sulfur dioxide and hydrogen fluoride, which endanger the health of residents. Planting trees, planting grass, planting flowers, expanding the area of ​​green plants, can spit oxygen absorption, purifying the air, block the dust, etc., beneficial to human health. Due to the densely populated urban areas, dense roads and large buildings, the area available for afforestation is relatively reduced. In order to solve this contradiction, more foreign countries to take roof greening to solve. Roof greening is in all kinds of buildings