Will cigarette smoke damage my lens?

Alright, so most of my family smokes, and I take pictures of them. But will the cigarette smoke damage my lenses? Say if they blew smoke into my direction and it touched the lens? I'm just worried about my Sigma fisheye, even though Sigma makes a pretty tough lens. Also, will my DSLR be okay? I use a Canon Rebel XSi, don't wanna ruin my baby. Thanks!