Cigarette butts are the most littered item on the planet. People toss out an estimated 4.5 trillion cigarette butts each year, and that number may double by the end of 2025 as e-cigarette use grows.

Social smoking—smoking sporadically and only in social settings—can be seen as a harmless vice. But does it carry the same ...

A new analysis of existing studies co-led by a University of Massachusetts Amherst public health researcher finds that nicotine e-cigarettes consistently help adults quit smoking, a conclusion that ...