Exposure to ammonia and acute respiratory effects in a urea fertilizer factory.

Personal exposures to ammonia and acute respiratory effects were determined in workers at a urea fertilizer factory in Bangladesh. Full-shift personal exposure to ammonia was measured using a PAC III direct reading instrument and Drager diffusion tubes. Respiratory symptoms were elicited by a questionnaire study (n = 113), and preshift and postshift lung function (FVC, FEV1, and PEFR) were tested using spirometry (n = 88). Urea plant workers had higher mean exposure to ammonia and prevalence of acute respiratory symptoms than did workers in the ammonia plant. The symptoms with highest prevalence in the urea plant were chest tightness (33%) and cough (28%). FVC and FEV1 decreased significantly across the work shift among urea plant workers. The higher level of exposure to ammonia in the urea plant was associated with an increased prevalence of respiratory symptoms and an acute decline in lung function.