Air pollution referable to increased ambient levels of sulfur dioxide and suspended particulates is associated with increased episodes of acute bronchitis and is also causally related to some cases of chronic bronchitis. Oxidant air pollution is associated with abnormalities of pulmonary function in children and is a major contributory factor in COP, especially bronchitis, in some areas of the United States. The relationship of nitrogen dioxide atmospheric contamination to COPD is still controversial. In our opinion, the epidemiologic studies conducted to date have been inadequate and further elucidation is indicated. Cadmium fumes and compounds have been found to be instrumental in the development of some cases of chronic bronchitis and emphysema in Sweden. This association is unproved in the United States and warrants a thorough clinical and epidemiologic evaluation.
We compared respiratory variables in 441 grain elevator workers with 180 civic outside laborers in Thunder Bay. The grain handlers had a lower frequency of both positive skin reactions to pollens and molds and a family history of asthma, which suggests that they may have been self-selected for a decreased tendency to develop allergic respiratory disease. There was a higher frequency of cough and rales and a small decrease in forced vital capacity and forced expiratory volume in one sec among the grain handlers, as compared to the civic workers matched for smoking. However, these differences between grain and nongrain workers were small in comparison to those between smokers and nonsmokers. There was no clear indication of a worsening of respiratory functions that could be attributed specifically to duration of employment as a grain elevator worker.