Impact of preventive measures on welding fume exposure among welders, robot operators, and bystanders: Air and biomonitoring

OBJECTIVE: This study assessed occupational exposure to mild steel welding fumes among manual welders, welding-robot operators, and bystanders in two Swedish manufacturing companies, and evaluated the impact of preventive measures. METHODS: Welding aerosol was characterized by size distributions and number concentration, size-fractionated mass and metal composition, and morphology. Exposure to respirable aerosol and metals was measured at baseline and follow-up after company-led preventive measures. Different local exhaust ventilation solutions and the effective protection factor of powered air-purifying respirators were evaluated. Metals in blood and urine were assessed in exposed workers sampled on Monday and Friday at baseline and follow-up, and in an unexposed reference group. RESULTS: ; a 91 % reduction). Median Mn levels were below limit values for all groups at follow-up. Urinary Mn broadly reflected these trends. Powered air-purifying respirators provided low effective protection and point exhaust ventilation was more efficient than alternative solutions. CONCLUSION: Comprehensive preventive measures reduced welding aerosol exposure across worker groups. Continued improvements are needed to ensure long-term protection for welders and bystanders.