The rain stopped and the heat exploded. In the past few days, the sun was like a fire, the temperature was rising steadily, and air conditioning, WIFI, and watermelon became daily routines. Some people say that my life was given by the air conditioner. But everything has two sides, and reliance on air conditioning to continue life is risky. Diseases caused by air conditioning are commonly known as “air conditioning diseases.” Air-conditioning disease is also called air-conditioning syndrome, which can occur at all ages, especially infants, the elderly, and people with poor physical resistance. It is mainly caused by dry air, cold irritation and microbial growth. Strictly speaking, air conditioning disease is not a disease, but a series of diseases. The most common one is upper respiratory tract infection, which manifests as fever, headache, dizziness, cough, sputum expectoration and other symptoms; it can also cause gastrointestinal diseases, manifested as nausea, vomiting, diarrhea and loss of appetite; there are also some older patients There will be pain in the cervical spine and joints. Many patients with allergic rhinitis and asthma have an increased frequency of attacks in an air-conditioned environment. In addition to the above-mentioned common diseases, the diseases caused by air-conditioning are particularly noteworthy as “air-conditioned lungs.” “Air-conditioned lung” actually refers to Legionella pneumonia, and the culprit is Legionella. Legionella is a relatively special pathogen, an aerobic gram-negative bacillus. Legionella is also known as atypical pathogen. Legionella pneumonia is the most severe form of atypical pneumonia, and the fatality rate without effective treatment is as high as 45%. There is currently no evidence that it spreads from person to person. Pregnant women, the elderly, and those with weakened immune functions are high-risk groups of Legionella pneumonia. There are more men than women in general, and the incidence occurs in late summer and early autumn. Because Legionella is most suitable for living in water at 40°C to 45°C, it is often inhaled through water supply systems, air conditioners and atomized inhalation, causing respiratory infections, and it can also present a small outbreak. The initial stage of Legionella pneumonia is similar to upper respiratory tract infection. It manifests as chills, fever, fatigue, weakness, and myalgia. A large proportion of patients often have painless diarrhea, watery stools, or are accompanied by symptoms such as nausea and vomiting. Some will suddenly onset after the incubation period of 2 to 10 days, with high fever, cough, chest pain, and hemoptysis. When the progress is rapid, progressive dyspnea may occur. Nervous system symptoms are common, such as mental disorders, headaches, disorientation, etc., and can also cause endocarditis, myocarditis, and even shock. Legionella pneumonia accounts for 1% to 8% of community-acquired pneumonia requiring hospitalization. In patients with legionella pneumonia, blood routine tests suggest leukocytosis, left nucleus shift, and lymphopenia; most patients have hyponatremia and low blood phosphorus; urine routine tests suggest mild hematuria and proteinuria, and biochemical findings suggest abnormal liver function. When pneumonia is accompanied by encephalopathy, hematuria, abnormal liver function and hyponatremia, Legionella infection should be suspected. Blood culture, sputum culture and chest CT examination are also important basis for diagnosis. For treatment of Legionella pneumonia, macrolide drugs such as erythromycin, roxithromycin, clarithromycin, and azithromycin are preferred, and third and fourth generation quinolones, such as levofloxacin, moxifloxacin, etc., can also be used . To reduce the occurrence of air-conditioning diseases is mainly prevention. The air-conditioning must be professionally cleaned before using the air-conditioning every year. Don’t adjust the temperature too low during use. Don’t turn on the air conditioner for 24 hours. Remember to open the window in the morning and evening for ventilation. Drink plenty of water in the air-conditioned room to keep the respiratory tract moist.