You've heard of secondhand smoking, but did you know there is also thirdhand smoking? The children's health advocacy group Healthy Child Healthy World says thirdhand smoking is when toxic residues left behind from a smoker remain on things like clothes, fabric, furnishings, walls, bedding and other porous surfaces in a room. While the simplest step to protect children is to avoid smokers altogether, that can't always be the case. If you go into a room that has traces of smoke, open a window and use fans to circulate air. Ask people who smoke to change clothes and wash hands before interacting with infants and children.