Various harmful irritants to the respiratory tract may aggravate the condition of patients with chronic obstructive pulmonary disease, air pollution, inhalation of smoke and irritant gases, exhaust gases from fossil fuels or kitchen fumes, etc. The reason why the incidence is higher in rural areas than in cities, in particular, is that rural living habits, such as heating with firewood, coal or biofuels, can produce harmful gases that can aggravate the condition of slow-onset lung. A World Health Organization survey found that women exposed to indoor smoke were three times more likely to develop chronic bronchitis and other chronic obstructive pulmonary disease than women who cooked and heated with electricity, gas and other cleaner fuels. Among men, exposure to this neglected risk factor increased the risk of developing chronic respiratory disease by almost a factor of one. Thus, indoor air pollution is responsible for about 700,000 of the 2.7 million deaths caused by slow-onset lung worldwide. Smoking also contributes to the increasing incidence of COPD, and data from the 2007 edition of the Chinese Clinical Guidelines for Smoking Cessation show that smoking causes 45% of COPD deaths. The dangers of secondhand smoke should not be underestimated. According to a study conducted by the Chinese Center for Disease Control and Prevention in Guangzhou, exposure to secondhand smoke can increase the prevalence of slow-onset lung and respiratory symptoms; according to the results of the study, an estimated 1.9 million deaths from slow-onset lung among current non-smokers in China are attributed to the dangers of secondhand smoke. In addition, long-term living or exposure to places with harmful gases or particles such as grain dust and chemical materials, as well as keeping pets exposed to a large number of fur dust mites and excessive renovation inhaling harmful gases can be factors for the increase of patients with chronic obstructive pulmonary disease. The onset of a number of patients with chronic obstructive pulmonary disease is caused by the patient’s repeated colds. The change of seasons, children and elderly people’s resistance is relatively weak, less clothes, not covered tightly these are the causes of children and elderly people’s colds. The nasal cavity and the mouth are two organs of the human body that are in direct contact with the outside world, where the nasal cavity is in direct contact with the air, and the dirty, bacterial and fine particulate air is inhaled into the human body. The patient’s repeated colds inevitably cause respiratory infections, and a cough that is not good for a long time will transform into slow-onset lung. Chronic cough is usually the first symptom of slow-onset lung. The cough is intermittent at first, heavier in the morning, and later in the morning and evening or throughout the day, but the cough is not significant at night. The cough is usually followed by a small amount of mucus sputum, some patients cough more in the early morning; when combined with infection, the sputum volume increases, often with purulent sputum. Shortness of breath or dyspnea is the hallmark symptom of slow-onset obstructive pulmonary disease. It appears early only when the patient has strenuous exercise, and then it gradually worsens to the point that shortness of breath is felt even during daily activities and even at rest. Some patients, especially the severe ones, have a feeling of wheezing, while a tightness in the chest occurs after strenuous exercise, which is related to the effort of breathing and the capacitive contraction of intercostal muscles and other muscles. Therefore, active prevention and treatment of colds is the best way to prevent slow-onset lung.