Within the last five years, e-cigarettes and personal nicotine vaporizers have exploded in popularity, and with that popularity has arisen a growing subculture. Search "vaping" in YouTube and the result is nearly 400,000 videos offering everything from tips for building your own e-cigarettes and hookahs, to reviews of popular nicotine liquid flavors, to posturing puffers showing off the thickest clouds their lungs can muster.
But look for scientific information about the devices — which are not subject to the same federal oversight as traditional tobacco products — and the sources become scant. According to the U.S. Food and Drug Administration, which is now seeking to extend its authority to regulate tobacco to include e-cigarettes and the nicotine-containing "e-liquid" they vaporize, the potential risks and benefits of these devices have not been fully studied. Nor has the amount of nicotine or other potentially harmful chemicals inhaled during their use.
People are studying these things rapidly, but the technology is evolving just as rapidly, and there are big gaps in our knowledge about them," said Bucknell Professor Jim Baish '79, biomedical engineering. "The FDA's questions are still very much open questions."
Since last year, Baish and a small team of Bucknell student and faculty researchers have been working to fill in some of the gaps in our knowledge of e-cigarettes.
Doing so has required leveraging a diverse set of University resources. Baish, along with chemical engineering professors Tim Raymond '97 and Dabrina Dutcher and students Mark Daley '17 and Jordan Berger '17, have measured particles with the engine exhaust particle sizer from Bucknell's powertrain lab. They've done metallurgical analysis of heating coil wire used in vaporizers with the geology department's environmental scanning electron microscope, and used a variety of equipment from Raymond and Dutcher's aerosol lab and the College of Engineering's environmental lab to study concentrations of nicotine and other molecules expelled by e-cigarettes in particle and vapor form.
The project has even required building new equipment that mimics the way e-cigarette users puff on vaporizers.
"People who smoke cigarettes will take puffs of a certain duration with a certain repetition rate, and there are standards for how to study these things, because cigarettes have been studied for a long time," Baish said. "But people use e-cigarette devices differently, so they puff with a different pattern. People often puff on them for longer. It's not necessarily stronger; it's just different."
Daley's first task as a research intern this summer was to design and build a computer-controlled e-cigarette puffer. The device, a small plastic box connected to rubber tubes and a 3-D printed mouthpiece that holds a vaporizer, uses an Arduino programmable microprocessor to automatically regulate puff duration, puff spacing, voltage given to the e-cigarette and flow rate. Turn it on and it takes uniform puffs at regular intervals, expelling vapor that can be collected and analyzed.
"Through this project I've done design work," said Daley. "I've learned how to use gas chromatography-mass spectrometry and how to do chemical analysis. I've done some basic coding for data analysis. It's been a very self-driven, multi-dimensional project on something that millions of people are using."
Armed with a uniform method for gathering data, Baish and Daley have begun examining the availability of nicotine in the particles and vapor expelled by e-cigarettes.
"In the particle phase nicotine is probably going to absorb more slowly, through membranes, versus the vapor, which is going to get deeper into the lungs and will be absorbed much faster," Baish said.
Dutcher and Raymond are meanwhile studying other molecules produced by heating e-liquid, which in addition to nicotine usually contains the relatively innocuous chemicals propylene glycol and glycerol. A study published in the New England Journal of Medicine indicated e-cigarettes might produce formaldehyde, a carcinogen, but Dutcher is skeptical of those findings and wants to repeat the experiment herself.
"They were running the device very, very hot, and in fact they never measured formaldehyde; they measured something they said would probably be in equilibrium with formaldehyde," she said. "I want to redo the work and either verify it or say, 'No, that's sensational. No one actually runs them this hot.'"
Dutcher plans to present some of her findings at the American Association for Aerosol Research Annual Conference in October, and Berger will present a paper based on his research at the American Society of Chemical Engineers Annual Meeting in November. The researchers are quick to point out that they don't have an agenda against e-cigarettes — Baish concedes the devices show promise to be much less harmful than smoking traditional cigarettes — they've simply been attracted by the explosion in popularity and rapidly developing sophistication of the devices.
"Everything is evolving," Raymond said. "You have single-coil and now dual-coil vaporizers, they all go to different wattages, and then you have different liquids, all with different additives and nicotine levels. There are a lot of unknowns in a lot of different areas. You could publish hundreds of papers on this if you spent forever looking at it."
Dutcher's interest even goes beyond nicotine to other, potentially beneficial uses for the devices.
"I have an interest in drug delivery in the aerosol phase," Dutcher said. "That has huge implications for treatment of diseases like tuberculosis, something we're still really bad at. I'm really interested in how these work, not because I care about nicotine, but because I'm interested in seeing if they could ever be used in a different, more helpful way. You have to completely understand the device before you can do any of that."