After quitting smoking, the lung tissues that have been damaged can be restored to a certain extent, but not necessarily back to normal. Tobacco contains a large number of chemicals, which will directly affect the respiratory system and damage the lung tissues, resulting in weakened elasticity of the lungs and decreased lung ventilation capacity, which can easily induce asthma, shortness of breath, and dyspnea. Therefore, as long as you continue to smoke, the damage to your lungs will remain. When the source of these chemicals is reduced after quitting smoking, it will not continue to exacerbate the lung damage, but the lung damage will continue to develop for some time after quitting smoking. Lung tissue that has been smoked for a short period of time and is not severely damaged may recover to its original level, but for more severe damage, such as complicated chronic obstructive pulmonary disease (COPD), the disease tends to progress more gradually. As you quit smoking, your circulatory and respiratory systems will gradually improve, and in addition to the obvious reduction in dry cough and sputum, the risk of lung infections will gradually decrease. If you want to quit smoking, it is recommended that you visit a hospital smoking cessation clinic.