Exposure to Smoke and Pollutants

Exposure to chemical fumes and organic dust such as cotton, grain, or wood dusts has been shown to adversely affect the airways. Coal miners, for instance, have a higher prevalence of chronic bronchitis, while workers exposed to cadmium (a metallic element that is a by-product of zinc) may contract emphysema. Indoor air pollution from biomass fuel (plant materials and animal waste used for cooking and heating in poorly vented dwellings) has also been implicated in the development of COPD.

Chronic exposure to pollutants is also responsible for both chronic bronchitis and emphysema. Exposure to smoke and indoor and outdoor pollutants contributes to airway obstruc­tion through stimulation of abnormal broncho­constriction, stimulation of chronic mucus production, reduced ability of the cilia to keep the mucus moving, and inhibition of the ability of the macrophages to aid the immune system. Inhala­tion of environmental irritants (eg, occupational chemicals) is also a cause of exacerbations of COPD.

Although occupational exposure to inhaled substances independently increases the risk for COPD, it is clear that the size of its contribution is small in comparison to the effects of tobacco exposure.