Much is still unknown about the health effects of vaping, which some see as a safer alternative to cigarette smoking and others see as a serious hazard to public health, especially for children and young adults. While several studies have been conducted to determine how vaping really compares to tobacco smoking, fewer studies have gathered a full picture of all the compounds contained in e-liquids and e-cigarette aerosols. A research team at Johns Hopkins University sought to capture this bigger picture through non-target liquid chromatography-high resolution mass spectrometry (LC-HRMS) analysis and discovered more than 1,000 unknown compounds as well as six substances that could be potentially harmful.
The team investigated both e-liquid and vape aerosols from four popular e-cigarette brands, using tobacco-flavored products for all of the tests. The researchers utilized a chemical fingerprinting technique to characterize the contents of the samples, which included one disposable product, two pod-based products and one tank-based product. The e-liquids and aerosols, the latter of which were collected using a condensation device, were tested via non-target, quantitative LC-HRMS analysis, and a total of nearly 2,000 compounds were detected, the vast majority of which were unidentified.
Of the compounds that were identified, six were considered to be potentially harmful, including three chemicals that had never before been detected in e-cigarettes. This included three industrial chemicals, a pesticide, and two flavorings that have been linked to possible toxic effects and respiratory irritation, according to the researchers. Additionally, the researchers found caffeine in two of the four products, something that had previously been seen in chocolate and coffee-flavored vape products but that the researchers were surprised to discover in tobacco-flavored e-liquids.
In three of the four products, the number of compounds detected increased from the e-liquids to the aerosols, and the researchers also found higher proportions of condensed-hydrocarbon-like compounds in aerosols. These compounds are associated with combustion and can be toxic, although vape product manufacturers say combustion does not occur during vaping. Many of the chemicals found in the products, including caffeine, have not been disclosed by the manufacturers, the researchers said. The study was published in Chemical Research in Toxicology.
“Existing research that compared e-cigarettes with normal cigarettes found that cigarette contaminants are much lower in e-cigarettes. The problem is that e-cigarette aerosols contain other completely uncharacterized chemicals that might have health risks that we don’t yet know about,” said senior author Carsten Prasse. “More and more young people are using these e-cigarettes and they need to know what they’re being exposed to.”
Although vaping is often viewed and marketed as an alternative to cigarette smoking, co-author Ana M. Rule noted that many children and teenagers who have never smoked have still picked up vaping.
“For them there is no risk reduction, only increased risk,” Rule said.
Photo: Johns Hopkins researchers analyzed vape product e-liquids and aerosols using liquid chromatography-high resolution mass spectrometry (LC-HRMS). Credit: Will Kirk/Johns Hopkins University