Vertical gardens: A green solution to roadway noise and air pollution

Posted in: Bridges, Environmental, Transportation

Robust highway systems offer economic and societal advantages, but their impacts include concentrated noise and air pollution. To combat these effects, the citizens of Mexico City are using vertical gardens to create green space, reduce traffic noise and remove air pollutants.

The effects of air pollution are well known – smog, health risks and climate change are each highly discussed topics. Surprisingly, noise exposure carries risks as well. Roadway noise exposure has been linked to physical and psychological problems such as feelings of isolation, anxiety, depression, high blood pressure, insomnia and fatigue.

In most cities, massive acoustical barriers, typically made of concrete and standing an average of 14 feet, bracket America’s urban and suburban highways to combat noise. Since the 1970s, when the barriers first started sprouting, nearly 3,000 miles of barriers have been erected. According to USDOT officials, California alone has 760 miles of sound walls. Florida has 252 miles. Structure designers originally championed these barriers as beneficial to communities. However, acoustical noise walls typically aren’t attractive and often increase the feeling of physical isolation.

In Mexico City, a group of citizens are using the built environment in a unique way to eliminate noise and air pollution. Mexico City is one of the most populated metropolitan areas on the planet, with over 20 million residents and 3.5 million vehicles. These factors, combined with other regional and environmental elements, create an atmosphere that is ripe for air pollution.

Created in 2012, the Via Verde project began constructing environmentally-friendly vertical gardens on structural columns that support flyovers and elevated roads around Mexico City. Since then, more than 640,000 square feet of vertical gardens have been planted on over 1,000 columns on the city’s Beltway. The project aims to grow enough plants to eliminate lingering carbon emissions and lower noise pollution. One estimate even puts the decrease in vehicular noise pollution by ten decibels; better than the reduction experienced by typical noise wall construction in the United States.

The “air plants” are placed in a dense cloth that the plants can root into. The plants use a natural rainwater irrigation system for nourishment. Large columns are also placed between the plants and the structural columns to prevent the plants from damaging the roadway structures.

As large cities look to reduce noise and air pollution, vertical gardens can do both while bringing green space to urban environments. Could these vertical gardens work stateside?

Dustin Wolff, AICP

About the Author

When he works on development and preservation plans, Dustin Wolff, AICP, keeps in mind that communities need to evolve. “Helping people shape their futures is a rewarding and humbling responsibility,” he says. “The built environment has a profound effect on our lives. Decisions we make today will be felt for years to come.” He also enjoys visiting cities around the U.S. to experience what makes them special.

Read more posts by Dustin Wolff, AICP

One response on “Vertical gardens: A green solution to roadway noise and air pollution

  1. I never thought about how one can turn ordinary concrete barriers into massive plant boxes to decrease the feeling of physical isolation. If I were to improve my community as a mayor, I would have concrete walls that can also store plants in every home. In that way, they would not only serve as a way to siphon off the town’s carbon dioxide emissions but also serve as a green thumbprint to our town that will make it stand out from other communities.

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