Cigarette smoke irritates the lining of the nasal cavity and throat causing swelling and catarrh. If the nasal passages become congested it is difficult to breathe through your nose because the airflow is decreased. The likelihood of snoring increases as more cigarettes are smoked per day because the congestion increases with each cigarette. Even passive smoking can cause inflammation of the nose and throat passages, thus increasing the risk of snoring. Children of parents who smoke are more likely to be affected by snoring than children of non smoking parents. If you cannot stop smoking you can modify the effects by having your last cigarette at least 4 hours before you go to bed. This will give your body sufficient time to reduce the effects of the cigarette smoke and help you to sleep without snoring.