When winds loft fine desert dust high into the atmosphere, iodine in that dust can trigger chemical reactions that destroy some air pollution, but also let greenhouse gases stick around longer. The finding, published today in the journal Science Advances, may force researchers to re-evaluate how particles from land can impact the chemistry of the atmosphere.
“Iodine, the same chemical added as a nutrient to table salt, is eating up ozone in dusty air high in the atmosphere,” said Rainer Volkamer, a CIRES Fellow and professor of chemistry at CU Boulder. Volkamer led the team that made precision atmospheric measurements by aircraft over the eastern Pacific Ocean several years ago. The new finding, he said, has implications for not only air quality, but climate, too—iodine chemistry can make greenhouse gases stick around longer and should give us pause to re-think geoengineering schemes involving dust.
“Our understanding of the iodine cycle is incomplete,” Volkamer said. “There are land-based sources and chemistry we didn’t know about, which we must now consider.”
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