" I did not see the white people, only the black: and as I watched I swore I could see fumes rising from their mouths—fumes rolling out of their mouths like exhaust, and I could see that every black person had the same small cloud of angry smoke coming out of his or her mouth and nose, a haze rolling up off the street like exhaust, filling the air, the white people breathing all that and not knowing it. Someone "

― Ben H. Winters , Underground Airlines