This article originally appeared on the Urban Times website
Urban motorways are some of the most polluting parts of cities, why should we accept this? Here are five reasons to green these polluting streets based on retrofitting them with living walls.
1. Reduce Air Pollution
The World Health Organisation (WHO) reports that in 2012 air pollution exposure accounted for around 7 million deaths worldwide, which represents one in eight of total global deaths. This has led the WHO to classify air pollution as the world’s largest single environmental health risk, and most of it concentrated in cities. Reducing air pollution in cities has the potential to save millions of lives.
Urban motorways are a significant contributor to world air pollution, so mitigating the effect of these roads on air quality could be an important step in the drive to reduce air pollution. Lowering speed limits on city motorways would reduce emissions, as would limiting traffic, and retrofitting green walls alongside the motorways to absorb and capture the emitted particulate matter. Planting algaeand wildflowers in urban areas has been proven to capture nitrogen oxides and carbon.
2. Reduce Noise Pollution
People living near urban motorways often suffer from intolerable noise pollution 24-hours a day. The effects of this are not limited to annoyance and sleep disturbance, but prolonged exposure to noise pollution can have serious health implications including changes in the immune system and birth defects.
Erecting green walls on elevated roads or landscaping plants would help mitigate the sound pollution dramatically. Plants can add to the effectiveness of simple sound barriers by entrapping or absorbing sound vibrations, or even deflecting and reflecting and refracting noise.
3. Reduce Urban Heat Island Effect
Unlike plants that absorb radiation and emit vapour, concrete and tarmac absorb radiation and release it as heat. This leads to a phenomenon known as the heat island effect that sees temperatures escalate dramatically in built up areas. Urban heat islands not only contribute significantly to climate change, but in raising city temperature to exorbitant levels they impact on increases in serious illnesses and deaths during heatwaves.
Green interventions in cities can reduce the rate of heat absorption by 84 percent in the summer, which can significantly bring down the energy costs of cooling buildings. Reducing the energy burden of urban cooling through planting could help reduce the impact of increasing air conditioning usage which according to a recent study could explode tenfold by 2050.
4. Increase biodiversity
Green space in cities is increasingly coming at a premium. As cities grow the pressure to develop open space land mounts. In London alone, 215 hectares of open space land was lost between 2009-2012. This puts extra pressure on urban species, which are being increasingly squeezed out of city habitats.
Increasing the green space would help a range of ecosystems and species thrive in the city. Upshots of this include connecting us to nature and maintaining habitats for pollinating bees, which could support the urban agriculture growth that some have predicted is the future of food.
5. They Would Look Amazing!
Let’s face it, urban motorways are grey, dull, and ugly. A green overcoat would look both beautiful in comparison. Above all it would send a message that we do not have to accept our cities’ polluting present, these long stretches of green in our cities could capture the pubic’s imagination to inspire a new future.
What do you think about the possibility of urban motorways going green?