Some triggers involve specific irritants such as cigarette smoke, certain foods or chemicals in the environment, while others are 'non-specific' things like cold air, exercise and emotions. Although these alone are unlikely to trigger symptoms, if you have sensitive lungs, then they may produce symptoms.
Different people have different triggers.
Often more than one trigger is involved so, for instance, if you are sensitive to certain foods, these make your bronchi more sensitive with the result that breathing in cigarette smoke then triggers an attack. Show the doctor or practice nurse. Allergy testing may also be useful. Ask your doctor about this. Common triggers and what to do about them Airborne irritants Any substances you breathe in can become an allergen.