What the researchers determined is that in three e-cig devices, there was an increase in total aldehyde yield with increasing power applied to the power coil, while two devices showed the opposite trend. The aerosol yields were set at 25 puffs.

“Formaldehyde and acrolein yields for one device exceeded both the yield from combustible cigarettes (20 per day) and the OSHA limit at the maximum power level tested,” the researchers said.

“However, three of the five devices studied yielded less formaldehyde, acetaldehyde and acrolein than delivered by combustible cigarettes.”

The researchers said their study “demonstrates that large differences exist in the electronic-cigarette devices available in the marketplace, and that, depending on the device, changes in power applied to the atomizer can have dramatic, but different, impacts on both total aerosol yield and the formation of aldehyde compounds in the electronic cigarette aerosol.”

No definitive answers

The second study was by British American Tobacco Ltd. researchers. It was made public at the Society for Research on Nicotine and Tobacco conference in Chicago.