Most importantly, don't allow smoking in your car. This is a confined space and even opening windows is not enough to clear the air. Choose a babysitter or day care center who does not allow smoking indoors or in their car. Dine in smokefree restaurants. If you smoke make every effort to quit and keep the smoke away from children.
Smoking is also a fire hazard and nicotine if ingested can poison children.
So keep lighters, matches and tobacco products out of the reach of children. Never smoke in the house. You will keep your child safe from injury and harmful chemicals if you protect them from secondhand smoke.