Could green roofs help curb city winter air pollution crisis?

Posted by Maja Tomazin on Dec 12, 2016 4:05:19 PM

Paris is constantly entering into its emergency measures as the city struggles with exceptionally high air pollution levels. Controls on vehicles, free public transport and advice to limit intense sports and avoid large traffic sites at time of high circulation are just some of the measures being taken by the French government to protect residents from the effect of the most prolonged air pollution in the last ten years.

Paris is not the only one; Athens, Madrid and Ljubljana are just some of the Europeans cities currently taking urgent steps to control growing air pollution; a problem which according to the Organisation for Economic Cooperation and Development (OECD) is set to cause as many as nine million premature deaths a year around the world in the next four decades. And the World Health Organisation (WHO) has described this problem as the “world’s largest single environmental health risk”.

Unfortunately, reducing the emission of new air pollutants does not remove those that are already in the air.

So what can be done to help cities prevent this problem rather than finding quick-fix solutions?

Research has consistently shown how vegetation on green roofs traps the air particles and gas pollutants that contribute to air pollution. According to research presented in the 2014 Green Roofs White Paper, a 1,000-square-foot (or 93m2) green roof is capable of removing 40 pounds (18kg) of polluting particulate matter from the air. Eighteen kilogrammes of this material is the equivalent of emissions from 15 cars driving for a year.



What about the role green roofs play in reducing the harmful greenhouse effects of CO2?

Green roofs are created from a range of different sedums, grasses and mosses and all these plants need CO2 to survive.

Installing green roofs in cities can therefore mitigate the 'heat island' effect, an effect that warms many urban areas, by radically reducing CO2 levels and generating as much oxygen as consumed by adult person in one year*. Of course green roofs cut CO2 emissions in other ways too. As green roofs act as a powerful form of insulation, less CO2-emitting energy is required to be created to power heating or air conditioning.


Many cities are deciding to go green on their roofs

Many cities are deciding to go green on their roofs by encouraging and supporting property owners to install green roofs solutions. These solutions can also help building developers score extra points in Green Building Rating Systems.


Knauf Insulation’s Urbanscape® Green Roof System is the world first green roof system with a Life Cycle Assessment (LCA) and Environmental Product Declaration (EPD) that points out the main environmental benefits of the system.

According to the EPD, during the lifetime of an extensive green roof, 1m² of extensive vegetation will directly absorb up to 15 kg of CO² , due to improved energy efficiency. 1m² of green roof would also decrease CO² for additional 50 kg in a lifetime (cca 2,5 – 3 kg kg/m2 per year). Green roofs can also help cool buildings and the surrounding air through water evaporation. This in turn reduces the Urban Heat Island effect. It also has the double benefit of being a great thermal control element, saving building energy for heating and for cooling. Installing Urbanscape can also contribute to enjoy clean air with plants on green roofs not only filtering collected rainwater but also capturing 0.2 kg airborne particles from the air every year.


In all respects green roofs are becoming the norm. And that’s good news for everyone, particularly city dwellers.


Want to know more?

Access to the Urbanscape PET Report for selected city now and understand Green Roof benefits beter!

Read more about How Green Roofs contribute to final Green Building Ratings and download the product data there!

Check Urbanscape EPD - transparent declaration of the life-cycle environmental impact of a green roof!

Or simply download the Urbanscape Green Roof System brochure below!


Download Brochures Green Roof System


Topics: Heat island effect (UHI), air pollution, LEED, BREEAM, EPD