Fine particulate matter mainly refers to a class of pollutants, such as PM2.5, which are suspended in the air and easily enter the human respiratory tract. Since the human respiratory tract, including the nasal cavity and oral cavity have no way to block this type of fine particles, they are easily inhaled into the trachea, bronchi and alveoli. This will over time induce many respiratory diseases, such as bronchial asthma, chronic bronchitis, and even chronic pneumoconiosis, silicosis, and chronic eosinophilic pneumonia. This can easily cause chronic bronchial and emphysema, and even lead to chronic pulmonary heart disease.