France passes a law requiring new rooftops to be covered with plants or solar panels March 30, 2015 BY: TYLER FYFE Earlier this month France passed legislation in response to pressure from environmental activists that all buildings constructed in commercial zones must have sections roofed with solar panels or green spaces. According to smog readings by air pollution watchdog Plume Labs, the air pollution in Paris briefly became the highest in the world prompting the city to respond by making all public transit and bike-sharing programs free. In densely populated cities, green roofs can significantly improve air quality by absorbing pollutants while producing oxygen. A 2014 study by The Gulf Organisation for Research and Development found that plant-covered roofs act as a drain for nitrogen, zinc and lead—runoff of zinc and copper being 90 per cent in dissolved form. The roofs reduce the damaging effects of acid rain by raiding the PH value of rain and runoff water. This is the design for a sustainable high school planned to be built in Revin, France. Toronto was the first city in North America to pass a bylaw that maintained that green roofs must be included in the design of all new buildings. Although tree-covered roofs date back to ancient civilizations like Babylon, recently they have been embraced as a way of making cities more liveable by saving energy through a method that’s also quite fashionable. While these roofs were initially sought by cities as a way to reduce the costs of acquiring land in metropolitan areas for public parks, they have a significant affect on moderating temperature by acting as a passive-cooling system. Plants provide direct shading while reflecting incoming solar radiation and help cool buildings through the transpiration of water to reduce thermal loading. Green roofs also help to promote wildlife activity by providing temporary habitats for migrating birds, while also stimulating biodiversity by increasing decomposing organic material allowing organisms to thrive. Currently, Germany is the leader of green roof research with more than 10 per cent of houses having plant-covered roofs and that number increasing by 10-15 per cent each year. The Environmental Protection Agency estimates the upfront investment for green roofs to be $10 per square foot for modest roofs and $25 per square foot for more intense designs. However, these initial costs are offset by the benefits of decreased energy expenditure and the lengthened lifespan of green roofs. France is making significant effort to address the concern of growing rates of pollution having adverse affects on the health of citizens. Last year, the World Health Organization stated in apress release that outdoor air pollution has been classified as an environmental cause of cancer deaths. The country joins the ranks of forward-thinking cities that have enshrined a green mandate into law such as Toronto, Basel and Tokyo, who passed the Green Tokyo Plan in 2001.