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Member Research & Reports

Member Research & Reports

Yale: Juul Users Inhaling Chemicals Not Listed According to Yale Study

Yale researchers found that chemical reactions in flavored liquids of the popular Juul e-cigarette create unexpected chemicals that can irritate users’ airways.The researchers focused on acetals, which are chemicals that form when the common flavorant vanillin interacts with alcohols that carry the nicotine and flavors in e-cigarettes. Led by the lab of Dr. Julie Zimmerman, professor of chemical and environmental engineering at Yale, the study was published in the American Journal of Preventive Medicine.

Despite the popularity of Juul, little is known about the composition of its aerosol (commonly referred to as “vapor”). The researchers used a “vaping machine” custom-built in Dr. Zimmerman’s lab to analyze the chemical makeup of various flavors of the Juul refill cartridges

“We were able to detect these acetals both in the e-liquids as well as in the aerosol,” said lead author Dr. Hanno Erythropel, adding that this is the first report of the presence of glycerol acetals in e-cigarette aerosol.“People often assume that these e-liquids are a final product once they are mixed,” Dr. Erythropel said. “But the reactions create new molecules in the e-liquids, and it doesn’t just happen in e-liquids from small vape shops, but also in those from the biggest manufacturers in the U.S.”

In the Juul products tested, most of the acetals resulted from the reaction with glycerol. The researchers also noted that four of the eight flavors tested contained menthol, a compound used to counteract nicotine’s bitterness and that may increase nicotine intake.

Based on the results, the researchers recommend that future e-cigarette regulations address the formation of new and potentially toxic compounds, menthol levels, and the health effects of flavorants in e-cigarettes.

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