Opinion is divided on the harmful effects of e-cigarettes, another research now delves into the impact of second-hand smoking of e-cigarettes.

The news research by the University of Southern California states that e-cigarettes release toxins in the air. The research  quantified the level of exposure to harmful organics and metals in second-hand e-cigarette smoke and hoped to provide some insights  for the regulatory authorities to go forward.. 

Study findings showed that e-cigarettes are relatively safer than the conventional ones when it comes to passive smoking and second-hand smoke from e-cigarettes shows an overall 10-fold decrease in exposure to harmful carcinogenic particles.

But still researchers warn the amount of toxins e-cigarettes release is a matter of concern. Their study showed that e-cigarette smoke contains chromium, a toxic element. Nickel levels are four times higher than traditional cigarettes. 

"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," Constantinos Sioutas, professor at the USC Viterbi School of Engineering, and corresponding author of the study, said in a press release.

"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 tests for e-cigarettes were done in closed environments like offices and rooms, as these are the places that one is exposes maximum to e-cigarette smoke.  The researchers used a common traditional cigarette brand with smoke from an Elips Serie C e-cigarette, one of the most popular European brands to compare resutls.

The study was published in the Journal of Environmental Science, Processes and Impacts.