Cleans Air & Water
Green roofs and walls scrub urban air. The US EPA states that 1000 square feet of green roof and wall removes the particulate matter and CO2 from 78 automobiles each year. Green roofs and walls reduce greenhouse gas emissions in two ways. First, by absorbing CO2 directly. And second, by reducing the amount of energy required to cool or heat a building. Vegetated roofs and walls reduce heat gain in summer by 87% and heat loss in winter by 37%. In cities, buildings are responsible for up to 80% of CO2 emissions, according to Climate Central. Adding green roofs and walls is one of the best ways to address climate change locally.
In addition, planting a green roof adjacent to the HVAC units on the roof brings two additional air quality benefits. First, the intake air for the building occupants is cleaner. And second, the efficiency of the HVAC units is improved because the green roof cools the surrounding air. This reduces further the amount of electricity required and greenhouse gases generated.
Green roofs also help clean and save fresh water. As we adapt to climate change, we – especially those of us who live in the West – realize that the supply of fresh water is finite. Green roofs allow the building to capture and filter water that falls on it. Green roofs remove 95% of cadium, copper and lead, and 30% of the nitrogenand phosphorous from stormwater. And, green roofs save water by saving electricity. Did you know that water is required to create electricity. To the extent that green roofs, walls and infrastructure reduce electricity usage, they are conserving water. According to “The BIG THIRST,” to generate the electricity we use at home requires 250 gallons of water per person per day.