In a controversial new study, scientists are claiming that trees in Los Angeles are contributing to the city's air pollution, challenging conventional notions about the positive role they play in urban ecosystems. As New Scientist explains , the theory was born of a strange conundrum: despite efforts to decrease traffic exhaust and increase environmental protections, the ground-level ozone and microscopic particulate pollution that make up the city's smog have remained steady. Back in 2022, a team of scientists from Colorado and South Korea found that those stubbornly stable pollution rates were likely due primarily to a rise in "secondary" sources of pollution — and in this latest multi-institutional study, researchers suggest that trees and shrubs may be the culprit.
Published in the journal Science , this new research focuses on terpenoids, an organic chemical compound found in plant matter that generally acts as an antioxidant — but which, when released into the atmosphere, can combine with pollutants to make them more harmful. Upon release from plants, the discharge from terpenoids becomes what's known as volatile organic compounds (VOCs), which end up reacting to air pollution by creating the kind of ozone and fine particulate pollutants in question. What's worse, plants emit more VOCs due to rising temperatures and drought, both of which plague the City of Angels in particular .
To get to this jarring conclusion, the researchers out of Germany, CalTech, Berkeley, C.
