"A chemical reaction involving emissions from cars and buildings can negate their environmental benefits. New research shows what big cities can do about it."
"Oak trees with leaves like outstretched hands and thick, stately trunks reduce the effects of extreme heat around New York City’s five boroughs by shading sidewalks and sucking up planet-warming carbon.
These workhorses also naturally emit a chemical called isoprene. Alone, it is harmless. But when isoprene meets nitrogen oxides, a group of gasses emitted when fossil fuels are burned to power buildings and vehicles, the chemical reaction creates ground-level ozone, a harmful pollutant that can cause respiratory issues.
“The trees themselves don’t create any problems, in fact they solve a lot of problems for us in cities,” said Andrew Reinmann, associate professor of environmental science at the City University of New York and an author of a new study examining the isoprene emissions of city trees. “The problem is cars and fossil fuel combustion in cities that can essentially start to negate or take away some of the benefits that trees are providing us.”"
Austyn Gaffney reports for the New York Times August 20, 2024.
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