Respiratory symptoms and lung function abnormalities among machine operators in automobile production

Area of Science:

• Occupational Health
• Environmental Health
• Respiratory Medicine

Background:

• Metal-working fluids (MWFs) are used in machining operations and can pose respiratory health risks.
• Previous studies suggest potential links between MWF exposure and respiratory issues, but specific exposure-response relationships require further investigation.

Purpose of the Study:

• To compare respiratory symptoms and lung function between MWF-exposed machine operators and unexposed assemblers.
• To examine exposure-response relationships between respiratory health outcomes and MWF type, total aerosol, endotoxin, culturable bacteria, and fungi.

Main Methods:

• Cross-sectional study involving 183 machine operators and 66 assemblers from an automobile transmission plant.
• Data collection included questionnaires, spirometry, and cross-shift assessments of lung function and respiratory symptoms.
• Airborne and bulk samples were analyzed for total aerosol, endotoxin, culturable bacteria, and fungi.

Main Results:

• Machine operators exhibited higher airborne exposures to total aerosol, endotoxin, culturable bacteria, and fungi compared to assemblers.
• Machine operators reported significantly more respiratory symptoms, including cough, phlegm, and chest tightness.
• Exposure-response relationships were observed between respiratory symptoms and total aerosol, culturable fungi, and bacteria; lung function decrements did not differ between groups.

Conclusions:

• Respiratory symptoms are associated with MWF exposure, even at lower levels, indicating a need to reassess exposure thresholds.
• Further research is needed to explore fungal exposure sources beyond MWF in machining operations.
• While lung function was not affected, the prevalence of respiratory symptoms highlights the importance of controlling workplace exposures.