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Scientists make remarkable discovery after studying 'green roofs' on buildings: 'Can offer unexpected co-benefits'
Scientists make remarkable discovery after studying 'green roofs' on buildings: 'Can offer unexpected co-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% 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.
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In the study, Cheng's team found that irregularly shaped microplastics were captured by the rooftop soils better than smoother ones that shed from stretch clothing. Other anomalies were also noted.
"We were surprised to observe that fiber-shaped microplastics captured by the green roof system could become resuspended into the atmosphere under airflow disturbance," like windy conditions, Cheg said in the story.
The soil could also eventually become "saturated" with the small particles. Fascinatingly, earthworms were noted as a possible solution to metabolize the plastics, all per Anthropocene.
Eliminating plastic use is a way anyone can help. Ditching single-use plastic bottles, for example, can provide you with a better, planet-friendly water carrier and save you a couple of hundred dollars a year.
On a larger scale, research from Shanghai is proving the value of greener building topsides. The team intends to help grow the concept.
"A key next step is to validate these results under real-world conditions on full-scale green roofs. We are actively exploring opportunities to carry out such long-term field studies to better understand microplastic retention and release dynamics over time," Cheng said in the report.
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