While secondhand smoke created by electronic cigarettes is for the most part less harmful than that emitted by their tobacco-burning cousins, it still puts toxins into surrounding air, a study has found.
Secondhand smoke emitted by e-cigarettes was found to have only a tenth of the harmful particles found in tobacco smoke, and almost zero levels of organic carcinogens, but concentrations of some harmful toxic metals were determined to be appreciably higher, the researchers say.
E-cigarette secondhand smoke was found to contain the toxic element chromium, not present in traditional cigarettes, and nickel in levels four times greater than normal cigarettes, researchers at the University of Southern California are reporting in the Journal of Environmental Science, Processes and Impacts.
Several additional toxic metals such as zinc and lead were detected in e-cigarette secondhand smoke, although at lower levels than in normal cigarette smoke, they said.
"Our results demonstrate that, overall, electronic cigarettes seem to be less harmful than regular cigarettes, but their elevated content of toxic metals such as nickel and chromium do raise concerns," researcher Constantinos Sioutas says.
The study was initiated to provide data to regulatory authorities in the form of quantified levels of harmful metals and organics in secondhand e-cigarette smoke.
In the study, volunteer subjects smoked regular cigarettes and e-cigarettes indoors while researchers collected particles and studied the chemical content of the samples.
"The metal particles likely come from the cartridge of the e-cigarette devices themselves, which opens up the possibility that better manufacturing standards for the devices could reduce the quantity of metals in the smoke," says lead study author Arian Saffari.
The study participants smoked a common traditional brand of cigarette and a popular European brand of e-cigarette, and the researchers noted the results of further studies could vary depending on the brands chosen.
"Studies of this kind are necessary for implementing effective regulatory measures," Saffari says. " E-cigarettes are so new, there just isn't much research available on them yet."
E-cigarettes have been at the center of controvery, with the World Health Organization urging either strict regulations or an outright ban on their use indoors.
The Centers for Disease Control and Prevention warn that e-cigarettes may be more tempting than conventional cigarettes to young people who've never smoked before, suggesting once they try e-cigarettes they are more inclined to move on to regular tobacco cigarettes.
In India, a health ministry panel of experts has recommended a blanket ban on e-cigarettes, saying their overall safety has not been established.