The study - published in the Journal of Environmental Science, Processes and Impacts and led by co-author Prof. Constantinos Sioutas of USC - comes at a time when the World Health Organization (WHO) propose a ban on the use of e-cigarettes indoors.

Prof. Sioutas, along with colleagues at Fondazione IRCCS Instituto Nazionale dei Tumori (the National Institute of Cancer Research) in Milan, Italy, conducted the study to measure the level of exposure to harmful substances in secondhand smoke from e-cigarettes. By doing so, they hoped to provide regulatory authorities with valuable information.

They found that secondhand smoke from e-cigarettes has an overall 10-fold decrease in harmful particles and almost no organic carcinogens, which is likely because they do not burn organic material the way traditional cigarettes do.

But they also found that e-cigarette smoke contains chromium - a toxic element that is not present in traditional cigarettes - and nickel at levels four times higher than normal cigarettes.

The researchers say there were other toxic metals present in e-cigarette smoke, such as lead and zinc, though they were at levels lower than in normal 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," says Prof. Sioutas.

http://www.medicalnewstoday.com/articles/281762.php