It is highly unlikely that smoking does not pass through the lungs, as the nasal cavity and throat are connected to the lungs via the trachea and bronchi, and thus the gas and smoke inhaled from the nose or mouth will eventually enter the lungs. Therefore, after you start smoking, you will gradually become addicted and may not be able to get rid of it. When cigarettes are inhaled into the lungs through the mouth or nasal passages, the nicotine contained in the cigarette enters the bloodstream through the alveolar epithelium and travels through the body’s bloodstream to the brain. Nicotine interacts with the brain’s special receptors to develop addiction to smoking, and will stimulate the brain to release dopamine and other excitatory neurotransmitters, which will reduce sensitivity to nicotine for a long time, and will gradually increase the amount of smoking to compensate, leading to addiction. In addition, long-term smoking is prone to bronchitis, asthma or chronic non-obstructive lung disease. Studies have shown that tobacco smoke contains a large number of carcinogenic substances, which can easily cause a variety of cancers, such as lung cancer, oral cancer, nasal cancer, and so on. And tobacco dependence is a chronic addictive disease, smoking not only damage their own health, second-hand smoke will also bring some damage to the surrounding people, it is recommended that for the health of their own and their families to try to quit smoking.