Measurement of ozone concentration in breathing zone during arc welding

Abstract In 2024, Japan set 0.1 ppm as the administrative levels—assessed as a short-term (15 min) exposure limit—for ozone in the breathing zone. Ozone is reportedly generated by the metal inert gas and tungsten inert gas welding of aluminum. The Japan Engineering Welding Society has investigated welding in shipyards, bridge construction, and tank assembly. A field study on ozone concentrations in various welding environments shows that ozone is generated by other welding processes as well. However, except in the case of pulsed gas metal arc welding, measured ozone concentrations are below the 0.1 ppm the administrative levels during short-term (15 min) exposure. Moreover, measured ozone concentrations vary depending on the welding environment, including the welding method, welder posture, and airflow. Therefore, this study investigated differences in measured ozone concentrations during arc welding. Welding work environments were recreated, and ozone concentrations were measured. Additionally, the intensity of ultraviolet light, a cause of ozone generation, was measured, and its relationship with ozone concentration was examined.