Many of us are familiar with first-hand smoke and second-hand smoke, but what about third-hand smoke? Well, you better get familiar with it because according to a new study conducted by researchers at the University of California, Riverside, the effects of third-hand smoke may be just as deadly as first-hand smoke. Let’s break it down: First-hand smoke refers to the smoke inhaled by a smoker. Second-hand smoke refers to exhaled smoke and other substances emanating from a burning cigarette that can get inhaled by others. Third-hand smoke is the second-hand smoke that gets left on the surfaces of objects. Over time, these left over chemicals can age and becomes progressively more toxic.