Pneumoconiosis does not fall under the category of infectious diseases and is not contagious. Pneumoconiosis is primarily caused by the inhalation of large amounts of mineral dust containing selenium in living or production environments. This dust deposits in the alveoli and leads to disease. The disease is mainly due to the long-term stimulation of the lungs by dust in the alveoli, resulting in pulmonary fibrosis. Patients primarily exhibit symptoms of chronic cough, expectoration, and wheezing. Over time, complications such as pulmonary heart disease may also arise, making this a severe disease. However, this disease does not belong to the category of infectious diseases. It is mainly caused by exposure to inorganic dust in industrial and living environments, so it is not contagious, which is not a concern.