Vegetative "Green Roofs" Offer Health Benefits

A Tongji University research project has provided evidence that green roofs can remove microplastics from rainwater, according to Anthropocene.

The vegetative building toppers have long been used to help insulate structures, reducing heating and cooling costs. They can also reduce stormwater runoff. They consist of a waterproof membrane, soil, plants, and some other infrastructure needed to hold it all together. They also provide urban habitat for birds and insects, and can last twice as long as regular roofs, all according to the Government Accountability Office.

A lab-scale mockup in Shanghai demonstrated the ability to filter out the tiny plastic polluters. The roof was able to collect 97.5 percent of ground rubber, polyurethane fibers, and other microplastics that were added to simulated rainfall, per the lab summary.

"Our study highlights the powerful potential of urban green roofs to act as passive interceptors of atmospheric microplastics," research team member Shuiping Cheng, from Tongji University in Shanghai, said in Anthropocene.

Microplastics are turning up all over the place, including in wild animal feces, the deep sea, and human blood, according to multiple reports. Washing a load of clothes sheds millions of microplastics, per PBS News. A researcher at the University of Bonn in Germany has developed a fish gill-inspired filter to capture most of them from the machines.

The health impact of the prolific pollution is still being studied, but Harvard Medicine said that scientists are concerned about cancer and reproductive health risks, among other troubles.

In Shanghai, vegetative roofs top only a "small fraction" of the sprawling city of more than 24 million people. Anthropocene reported that those green building surfaces can capture nearly 62 tons of microplastics annually.

"These nature-based solutions can offer unexpected co-benefits in mitigating airborne pollution in densely built environments," Cheng said in the report.

The GSA added that the natural roofs can also limit the impact of urban heat islands, negating "increased energy consumption, heat-related illness and death, and air pollution" from concrete- and asphalt-abundant cityscapes.

NASA has reported that planet warming is contributing to increased heat wave risks that may make some places uninhabitable.