Effect of green roof on ambient CO2 concentration

Plants can improve air quality by removing pollutants. The air purification capability of plants has been receiving increasing attention because of the rapid deterioration of the environment. However, research on evaluating quantitatively the effect of plants on the environmental pollutant concentrations is still scarce. This paper studies the effect of a green roof on the ambient CO2 concentration as an example to assess the benefit of urban greening. The study comprises three parts: (1) Field measurement of the difference of CO2 concentration at a location in the middle of the plants in a small plot of green roof and one in the surrounding area, (2) Experiments to measure the plant’s CO2 absorption velocity and emission rate using a sealed glass chamber; and (3) Computer simulation of the CO2 concentration distribution around a green roof using the measured CO2 absorption velocity and emission rate to quantify the effects of the green roof on the ambient CO2 concentration.