ABOVE: In a wind tunnel experiment, silver birch was the best of nine types of trees at grabbing hold of fine particles in diesel exhaust.
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Breathing in traffic fumes is accepted as unhealthy, but whether landscaping with vegetation can protect people is a matter of debate. Modeling studies generally suggest that trees do not have a substantial beneficial impact on pollution levels, and may even worsen a situation by trapping pollutants in certain areas.
Now, a study finds that certain tree species are surprisingly efficient in scrubbing toxic particles from the air. Wind tunnel experiments demonstrate that leaves trap considerable numbers of particles with a diameter less than 100 nanometers. The group put nine tree species through their paces, with three clear winners in the top tier, the study, published May 16 in Environmental Science & Technology, finds.
Birch, the best-performing tree, removed 79 percent of these ultrafine ...
