*-- Scientists identify best trees for fighting roadside pollution --*
A pair of scientists in Britain have developed a new framework for selecting the best trees for fighting roadside air pollution.
To build their framework, Yendle Barwise and Prashant Kumar, scientists at the University of Surrey's Global Center for Clean Air Research, surveyed the scientific literature on the impacts of green infrastructure on air pollution.
Their research showed some plants are best at diverting and diluting plumes of toxic air, while others directly capture pollutants. Barwise and Kumar also identified plants that are more likely to end up with pollutants on their leaves.
The pair of air pollution experts hope their work -- published this week in the journal Climate and Atmospheric Science -- will guide the decision making of urban planners, landscape architects and garden designers.
Air pollution is one of the world's most significant environmental health problems. Earlier this year, scientists found air pollution is responsible for shortening the human lifespan by an average of three years.
"Vegetation can form a barrier between traffic emissions and adjacent areas, but the optimal configuration and plant composition of such green infrastructure are currently unclear," researchers wrote in their paper.
"We found that if the scale of the intervention, the context and conditions of the site and the target air pollutant type are appreciated, the selection of plants that exhibit certain biophysical traits can enhance air pollution mitigation," the two scientists wrote.
Barwise and Kumar identified 12 influential traits among 61 tree species that are beneficial for the construction for pollution-fighting green barriers. The best trees feature small leaves, dense foliage and lengthy in-leaf periods. Evergreens and semi-evergreens are best. Leaf complexity is also helpful, as are trees with particularly hairy leaves.
The two scientists organized their findings into a framework that can help planners find the right pollution-fighting trees for their particular project.
"We are all waking up to the fact that air pollution and its impact on human health and the health of our planet is the defining issue of our time," Kumar, founding director of GCARE, said in a news release. "Air pollution is responsible for one in every nine deaths each year and this could be intensified by projected population growth."
"The use of green infrastructure as physical barriers between ourselves and pollutants originating from our roads is one promising way we can protect ourselves from the devastating impact of air pollution," Kumar said. "We hope that our detailed guide to vegetation species selection and our contextual advice on how to plant and use green infrastructure is helpful to everyone looking to explore this option for combating pollution."
*-- Scientists discover plastic-eating microbe --*
 Scientists in Germany have identified a new strain of bacteria that breaks down the chemical building blocks of polyurethane, or PU, a polymer used to make a variety of plastic materials. In effect, the bacteria eats plastic's essential compounds.
Researchers detailed their discovery this week in the journal Frontiers in Microbiology.
"The bacteria can use these compounds as a sole source of carbon, nitrogen and energy," study co-author Hermann J. Heipieper, senior scientist at the Helmholtz Center for Environmental Research-UFZ in Leipzig, Germany and co-author of the new paper, said in a press release. "This finding represents an important step in being able to reuse hard-to-recycle PU products."
Polyurethane is used in everything from construction materials and footwear to refrigerator components and skateboard wheels. The polymer is prized for its lightweight, insulating and flexible properties, but recycling it is energy-intensive. Most polyurethane ends up in landfills, where it can release a variety of toxins, some of them carcinogenic.
In an effort to curb the problem of PU waste, Heipieper and his colleagues turned to microorganisms. Most studies have investigated on the ability of bacteria and fungi strains to break down oil-based plastics, but few have looked at polyurethane.
While surveying bacteria communities living among plastic waste, scientists identified and isolated a strain called Pseudomonas sp. TDA1. The bacteria showed promise in its ability to target the chemical bonds that form polyurethane plastics.
In addition to being able to eat polyurethane, the bacteria strain is part of a family of bacteria known for their ability to withstand toxins.
"That trait is also named solvent-tolerance and is one form of extremophilic microorganisms," said co-author Christian Eberlein, scientist at the Helmholtz Center for Environmental Research-UFZ.
Genomic analysis of the bacteria helped the researchers identify possible pathways for metabolizing the PU chemical compounds. Scientists hope further genomic investigations will reveal the extracellular enzymes, or exoenzymes, that the bacteria uses to trigger compound-degrading biochemical reaction.
If future research efforts are successful, scientists could engineer bacteria to more efficiently degrade polyurethane compounds. |
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