The effect of prolonged occupational exposure to the low concentrations of nitrogen oxides in combination with ammonia on chronic bronchitis and the lung function.

The purpose of this study was the assessment of the effect of low concentrations of nitrogen oxides and ammonia on the appearance of the chronic bronchitis symptoms and lung function. The material in total consisted of 183 workers employed in the Chemical Factory in Tarnów (Poland). The study methods encompassed the environmental factors in all places of work and the questionnaire based interviews with the lung function testing of the workers. The results obtained prove that prolonged effect of the exposure to nitrogen oxides, even below the accepted safety level, causes a more frequent appearance of chronic bronchitis symptoms and lower FMF values. This may signal the narrowing of bronchiole as a result of the exposure to nitrogen oxides, independent of the effects on the mucous membranes of the bronchi, demonstrated by the excessive prevalence of chest symptoms. There is no reason to believe, as based on the results of this study, that the effects of nitrogen oxides could be in any way dependent on the tobacco smoking or on the accompanying concentrations of NH3.