Aug 30, 2014 05:05 AM EDT By Staff Reporter, UniversityHerald Reporter

Second-hand smoke from electronic cigarettes might be less dangerous than smoke from traditional ones. However, they release toxins into the air, according to a new study by the University of Southern California.

For the study, the researchers compared smoke coming from a traditional cigarette to that of an Elips Serie C e-cigarette. They said that results varied according to cigarette brands.

The researchers said that electronic cigarettes are associated with 10-fold less exposure to harmful particles compared to their tobacco-laden cousins. Despite having less damaging organic compounds and lower toxic metal emissions, e-cigarette smoke did contain chromium and nickel four times higher than tobacco cigarettes. Lead and zinc were also present, but in lower quantities than regular cigarettes.

The study also found that second-hand smoke from e-cigarettes did not produce any polycyclic aromatic hydrocarbons - cancer-causing compounds called organic carcinogens - that are actually released into the air from the traditional cigarette smoke.

"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," said study author Constantinos Sioutas, a professor at the USC Viterbi School of Engineering, in a statement.

According to the Centers for Disease Control and Prevention, e-cigarettes can be more attractive to non-smokers than conventional cigarettes. Once habituated to e-cigarettes, youth can be tempted to try normal cigarettes.

"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," said Arian Saffari, a PhD student at USC Viterbi and lead author of the paper. "Studies of this kind are necessary for implementing effective regulatory measures. E-cigarettes are so new, there just isn't much research available on them yet."

The finding is published in the Journal of Environmental Science, Processes and Impacts.

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