Pulmonary Consequences Analysis of Exposure to Low Concentrations of Ammonia: A Historical Cohort Study in Fertilizer Industries

Background and Objectives: Pulmonary consequences of exposure to low concentrations of ammonia have been less studied. The purpose of this study was to model the pulmonary consequences of exposure to low concentrations of ammonia.   Methods: This historical cohort study was conducted in the fertilizer industries in 2019. The participants were divided into two groups of exposed (n=98) and non-exposed (n=105). The exposure level, pulmonary symptoms, and pulmonary function parameters were assessed using the NMAM 6016 and American Thoracic Society and European Respiratory society (ATS&ERS) protocols. Data analysis was performed using the IBM SPSS v. 22.0, and multivariate linear and logistic regression models.   Results: The ammonia exposure level was 4.80±1.54 ppm in the exposed group. There was no significant difference in most of the individual variables between the two groups (P>0.05). The frequency of all pulmonary symptoms was significantly higher in the exposed group compared to the non-exposed group (P<0.05). The highest prevalence of pulmonary symptoms in the exposed group was for cough (25.51%), wheezing (19.39%) and shortness of breath (18.37%). All lung function parameters were significantly lower in the exposed group versus the non-exposed group (P<0.05). The values of lung function parameters in the exposed group including FVC, FEV1 and FEV1 / FVC were 86.0%, 82.47% and 81.97%, respectively. Regression modeling results showed that ammonia exposure had a significant relationship with all pulmonary symptoms and lung function parameters (P<0.05).   Conclusion: The findings indicated that exposure to low concentrations of ammonia should be considered as a major risk factor in the prevalence of pulmonary symptoms and reduced lung function parameters.