Secondhand smoke is dangerous, especially for children, and the best way to protect your loved ones is to quit smoking, or at least to make sure that your house and car are smoke-free. When you smoke, most of the smoke does not go into your lungs, but into the air around you, which can be inhaled by anyone nearby. Secondhand smoke is the smoke you exhale, plus the smoke from the lit end of your cigarette. When friends and family members breathe in your secondhand smoke, it not only makes them unhappy, it can damage their health. People who breathe secondhand smoke regularly are more likely to develop the same diseases as smokers, including lung cancer and heart disease. Pregnant women who are exposed to passive smoking are more likely to give birth prematurely and their babies are more likely to have low birth weight and be at risk of death. And, children who live in smoky rooms are at higher risk for respiratory illnesses, asthma and allergies. How to prevent secondhand smoke The only way to protect your friends and family from secondhand smoke is to keep your surroundings smoke-free. The best way to do this is to quit smoking altogether. If you are not ready to quit, do everything you can to keep your cigarette smoke away from others and never smoke indoors or in your car. Secondhand smoke contains more than 4,000 irritants, toxins and carcinogens. Most secondhand smoke is invisible and odorless, so no matter how serious you think you are, those around you will still be breathing in harmful toxins. After smoking a cigarette, the smoke stays in the air for two to three hours, even with the windows open. Similarly, even if you smoke in only one room, the smoke will spread to the rest of the house. Children and passive smoking Passive smoking is especially harmful to children because their respiratory tract, lungs and immune system develop incompletely. Children who live in households where at least one person smokes are more likely to develop asthma, chest infections – such as pneumonia and bronchitis, meningitis, ear infections, coughs and colds.