I like this quote:
CASAA Scientific Director, Carl V. Phillips, summarized the importance of the study, saying "It has always been clear that e-cigarettes were much lower risk than smoking, but there was uncertainty about whether continuing to inhale a mix of chemicals posed a measurable risk. Even those of us who have long encouraged smokers to switch are a bit surprised that even the worst-case-scenario risks are so low. This study assures us that e-cigarettes are as low risk as other smoke-free tobacco and nicotine products, like smokeless tobacco and NRT. All of these products are about 99% less harmful than smoking, and so smokers who switch to them gain basically the same health benefits as if they quit tobacco and nicotine entirely."