Secondhand smoke,also known as environmental tobacco smoke,is a mixture of sidestream smoke from the burning end of a cigarette,pipe or cigar and smoke exhaled from the lungs of smokers.

• 二手烟，也称为环境烟，是指从香烟、烟斗或雪茄烟点燃端飘出的侧流烟与吸烟者从肺里呼出的烟的混合体。