Khumbu cough

The pollution in Kathmandu is terrible. Infact, a lot of the locals wear masks. Then you head to the mountain with dusty paths and low relative humidity. This all irrates the respiratory tract and the result is the "Khumbu cough". It keeps you and others awake at night and can be serious enough to break a rib. The best way to prevent it is to wear something over your nose and mouth so the air you breathe in is warm and moisturized. A ski mask, balaclava, or bandana works well. Getting a comfortable fit over the face is the problem - too lose and it falls down all the time - too tight and it is hard to breathe.