My father doesn't smoke, but recently he's been coughing in the mornings and feeling slightly tired. Has the doctor diagnosed chronic obstructive pulmonary disease? What are the signs of lung damage in non-smokers? (Hoai Vy, Hanoi)

I smoke a few cigarettes when I'm stressed or meeting friends. Am I at risk of lung disease? Recently, I've had a persistent cough for about two weeks. (Hai Nam, Ho Chi Minh City)

I often feel short of breath and have chest tightness in hot weather, especially when outdoors or exercising. Is this a sign of lung disease? (Minh Tuan, Hanoi)

Ms. Hong, 43, developed erythema, a dry cough, and shortness of breath; doctors diagnosed sarcoidosis, a condition where an overactive immune response causes numerous granulomas in the lungs.