I had a wonderful dog, a Pomeranian, named Mabel. While I never smoked in my home Mabel too was addicted to nicotine. At first I didn't realize it but any time someone lit a cigarette Mabel was right there sniffing at the air. The day I realized that she was hooked too I made sure she was not around anyone who smoked but unfortunately she was already hooked. Mabel would actually search for cigs especially when I would take her for a walk; if there was a cigarette on the ground she found it and would pick it up and suck on it. When all smoking stopped around her I think she had withdrawals but eventually they subsided.
So, not only is second hand smoke something to be concerned about around other people, it's a concern around pets too.
This was Mabel; my Heart.