Talk about treeson.
Trees were supposed to be the urban jungle’s salvation. After all, trees provide sweet, beautiful shade which helps cool the metropolis, a place prone to overheating thanks to a proliferation of surfaces like asphalt and concrete. And by pumping oxygen into the air—the same oxygen humans need to breathe— while also filtering out harmful air pollution, trees were supposed to help the eighty percent of Americans who live in urban areas breathe easy. But a new study out today in the journal Environmental Science & Technology has found that planting trees while doing nothing about underlying air pollution is a bit like putting spinach on your double bacon donut burger: you’re still going to die of a heart attack.
During heat waves, the researchers found, trees can emit volatile organic compounds (VOCs) that help make air pollution, especially ground level ozone pollution, as much as sixty percent worse.
“We were surprised that the contribution of the plants to air pollution was so high,” says lead author Galina Churkina, a senior fellow at the Institute for Advanced Sustainability Studies in Potsdam, Germany.
To be clear, this is still entirely our fault. On their own, the trees’ VOCs don’t pose a threat. But once in the air, they undergo a chemical reaction with Nitrogen Oxides (NOx) —a byproduct of burning fuel, like the gas that power our cars’ engines—that adds more ozone to the mix. NOx causes a host of negative health effects ranging from respiratory issues to heart attacks. At the same time, ground level ozone irritates respiratory systems, aggravates asthma and chronic lung disease, and can even cause permanent lung damage.
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Smog in China and India, air pollution