Certain fumes and vapors can cause the blood vessels of the susceptible person to swell and dilate, triggering a migraine headache. Carbon monoxide poisoning from a poorly ventilated environment can provoke a headache. Faulty furnaces in winter can be responsible for such fumes. The nitrites used in explosives can trigger a headache in susceptible persons who are employed in munitions plants. Smoking can provoke or intensify a headache. It can cause biological changes in the blood and blood vessels. Just being in a smoke-filled environment can provoke a headache in susceptible persons. Strong perfume and loud and irritating noises can also precipitate migraine headaches in some migraine sufferers. This may be associated with stress as well as change in environmental conditions.