Quitting smoking is one of the most important things that smokers with COPD or asthma can do for their health. Yet for many, it's also be one of the biggest challenges they face. Rather than giving up tobacco completely, a growing number may be turning to e-cigarettes, a recent study by Harvard researchers suggests.
E-cigarettes resemble ordinary cigarettes, but they're battery-powered and produce vapor rather than smoke. They are still tobacco products, however. The liquid they're filled with typically contains nicotine, flavorings, and other chemicals.