Parents who smoke often open a window or turn on a fan to clear the air for their children, but experts now have identified a related threat to children's health that isn't as easy to get rid of: third-hand smoke.
吸烟的父母常常会开窗或打开电扇，以此为他们的孩子净化空气，不过专家们最近发现了另一种与香烟有关的对儿童健康的威胁，而且更难对付——三手烟。