To investigate whether nitrite levels were abnormally high in expired breath condensate (EBC) from workers with asthma-like syndrome. Materials and methods: We measured the nitrite levels in EBC from 48 volunteer workers, including 25 smokers, with asthma-like syndrome before and after SO2 exposure and compared these levels with those from 44 nonexposed control subjects, including 23 smokers. Results: Baseline concentrations of nitrite in the workers before SO2 exposure were higher (19.31 ± 1.06 nmol/mL) than in the controls (13.08 ± 1.36 nmol/mL; P < 0.001). Acute SO2 exposure produced a significant increase in concentrations of nitrite (23.62 ± 1.36) compared to the baseline value (P < 0.05). Preexposure nitrite concentrations were similar in smoking and nonsmoking workers (17.85 ± 1.72 and 20.20 ± 1.59; P > 0.05). Conclusion: We concluded that nitrite levels in EBC are increased in the asthma-like syndrome induced by occupational SO2 exposure in an agricultural environment, suggesting the role of inflammation in the syndrome; this first application of the EBC method may be suitable in other field studies in occupational medicine.

To investigate whether nitrite levels were abnormally high in expired breath condensate (EBC) from workers with asthma-like syndrome. Materials and methods: We measured the nitrite levels in EBC from 48 volunteer workers, including 25 smokers, with asthma-like syndrome before and after SO2 exposure and compared these levels with those from 44 nonexposed control subjects, including 23 smokers. Results: Baseline concentrations of nitrite in the workers before SO2 exposure were higher (19.31 ± 1.06 nmol/mL) than in the controls (13.08 ± 1.36 nmol/mL; P < 0.001). Acute SO2 exposure produced a significant increase in concentrations of nitrite (23.62 ± 1.36) compared to the baseline value (P < 0.05). Preexposure nitrite concentrations were similar in smoking and nonsmoking workers (17.85 ± 1.72 and 20.20 ± 1.59; P > 0.05). Conclusion: We concluded that nitrite levels in EBC are increased in the asthma-like syndrome induced by occupational SO2 exposure in an agricultural environment, suggesting the role of inflammation in the syndrome; this first application of the EBC method may be suitable in other field studies in occupational medicine.