Pulmonary function tests for children are not particularly harmful to children, except that some of them may experience a temporary increase in coughing symptoms due to forceful exhalation during the pulmonary function test, which is transient and does not have a significant impact on children, and the pulmonary function test is a non-invasive test that requires the cooperation of children. Pulmonary function testing is a non-invasive test that requires the cooperation of the child. After the age of five weeks, routine pulmonary function testing is required to identify whether asthma is present, and after the occurrence of asthma, there is a significant decrease in pulmonary function.