Pulmonary nodules 3mm are tiny nodules, no clinical symptoms, mostly benign, belong to chronic inflammatory changes, do not need special treatment, only need dynamic follow-up 1 time per year high resolution CT of the chest can be. Pulmonary nodules 3mm are mostly seen in people who smoke for a long time and those who are engaged in dust work, including masons, chefs, coal miners, hairdressers, tailors, etc. Long-term exposure to dust makes it easy for tiny nodules to form in the lungs. Therefore, once a high-resolution CT of the chest reveals microscopic nodules in the lungs, further observation needs to be given, including a T-cell test for tuberculosis infection to find out whether there is a possibility of tuberculosis infection. Total white blood cell and neutrophil tests as well as calcitoninogen and C-reactive protein tests are performed for possible bacterial infections. If tumor markers are high, you also need to be alert for the possibility of early stage cancer. Therefore, pulmonary nodules of 3mm are early microscopic nodules, which only need dynamic and close observation, no special symptoms, and no special treatment.