Background: The increase in work-related respiratory complaints in artificially ventilated buildings have multiple causes, and intervention studies are a valuable approach to understanding possible mechanisms.
Study objectives: To analyze the effects of an intervention in a ventilation system with > 20 years of continuous use, and with a high rate of building-related respiratory complains.
Design: An epidemiologic study was done among individuals working in places with ventilation machinery and ducts with > 20 years of use, before and after intervention. Analysis of symptoms and logistic regression were performed to check the associations between air-conditioning intervention and reported symptoms.
Results: The air-conditioning intervention showed a protective effect on building-related worsening of respiratory symptoms (odds ratio, 0.132; 95% confidence interval, 0.030 to 0.575), naso-ocular symptoms (odds ratio, 0.231; 95% confidence interval, 0.058 to 0.915), and persistent cough (odds ratio, 0.071; 95% confidence interval, 0.014 to 0.356).
Conclusion: Intervention in high-risk occupational locations can be effective in improving perceived indoor air quality.