how do green roofs help air quality?
 Green roofs can improve air quality through increased evapotranspiration and the filtering and shading effect of their foliage, thus helping to ameliorate the urban heat island effect, especially in sparsely vegetated areas. In summer, the green roof protects the building from direct solar heat. In winter, the green roof minimizes heat loss through added insulation on the roof. Energy conservation translates into fewer greenhouse gas emissions. Benefit: Green roofs improve air quality Plant leaves trap dust particles from the air, and evapotranspiration cools ambient temperatures. Less ground level ozone, along with less heat is equal to less smog. 