Air Purifier Use and Respiratory Health in COPD Patients

Inclusion Criteria: * Age between 50 and 80 years old * Physician diagnosis of COPD * Living in Shanghai during the intervention period * Subjects who have no plans to change homes during the intervention period * Non-smokers and former smokers Exclusion Criteria: * Subjects living in a location other than home * Subjects with a history of alcohol abuse * Subjects with other chronic lung diseases, such as active tuberculosis, pulmonary fibrosis, cystic fibrosis, or alpha-1 antitrypsin deficiency * Subjects with a history of thoracic surgery * Subjects with a history of malignant tumors, such as lung cancer, liver cancer, or gastric cancer * Subjects with diagnosed chronic hepatic or renal insufficiency, such as liver cirrhosis, chronic viral hepatitis, or autoimmune liver disease * Subjects with acute myocardial infarction or unstable arrhythmia diagnosed within the past 6 weeks * Subjects currently participating in other interventional studies