Sun exposure is not usually good for the lungs, but it can promote vitamin D production and some antiseptic effects. Sun exposure is usually not good for the lungs. But sunbathing can promote the absorption of trace elements in the human body, promote the generation of vitamin D in the body, can prevent osteoporosis, rickets and other vitamin D deficiency diseases. At the same time, the ultraviolet rays emitted by the sun have a bactericidal effect. However, when ultraviolet light acts strongly on the skin, photodermatitis can occur, with erythema, itching, blisters and edema on the skin. Patients with severe allergy to UV rays may also experience redness, swelling and peeling of the skin. It is recommended that the best time to sunbathe is between 9:00 and 10:00 a.m. or between 16:00 and 17:00 p.m., when the solar radiation is weaker and sunburn can be avoided.