Exposure to dusts, fumes, strong acids, and other chemicals cause this type of bronchitis .
Smoking is a contributing factor.
Occupational exposure to dust in the work place is a risk factor. Associated diseases include chronic bronchitis , coal worker's pneumoconiosis , silicosis , and asbestosis . The incidence is 1 out of 1,000 people. Stop smoking if you are at risk. Early screening for changes on chest X-ray is advisable for those at risk.