Occupational exposure and human-health risk assessment of PAHs across different arc welding processes

Welding is a critical industrial process but remains a major source of airborne chemical contaminants, including polycyclic aromatic hydrocarbons (PAHs), which are persistent, bioaccumulative, and linked to oxidative stress and carcinogenicity. In this study, process-resolved field measurements were conducted to quantify exposure to the 16 U.S. EPA-priority PAHs during shielded metal arc welding (SMAW), gas metal arc welding (GMAW), and gas tungsten arc welding (GTAW). Personal breathing-zone sampling and high-performance liquid chromatography were used to characterize emission profiles, and U.S. EPA health-risk models were applied to estimate carcinogenic and non-carcinogenic hazards. PAH concentrations and resulting risk metrics consistently followed the order SMAW > GMAW > GTAW, with SMAW generating the highest cumulative burden and hazard indices exceeding accepted thresholds. GTAW produced the lowest emissions and correspondingly minimal risk. These findings suggest clear process-dependent variability in PAH exposure and underscore the need for targeted engineering controls to mitigate risks in the welding process.