title: Characterization of Tungsten Inert Gas (TIG) Welding Fume Generated by Apprentice Welders.
abstract: Tungsten inert gas welding (TIG) represents one of the most widely used metal joining processes in industry. Its propensity to generate a greater portion of welding fume particles at the nanoscale poses a potential occupational health hazard for workers. However, current literature lacks comprehensive characterization of TIG welding fume particles. Even less is known about welding fumes generated by welding apprentices with little experience in welding. We characterized TIG welding fume generated by apprentice welders (N = 20) in a ventilated exposure cabin. Exposure assessment was conducted for each apprentice welder at the breathing zone (BZ) inside of the welding helmet and at a near-field (NF) location, 60cm away from the welding task. We characterized particulate matter (PM4), particle number concentration and particle size, particle morphology, chemical composition, reactive oxygen species (ROS) production potential, and gaseous components. The mean particle number concentration at the BZ was 1.69E+06 particles cm(-3), with a mean geometric mean diameter of 45nm. On average across all subjects, 92% of the particle counts at the BZ were below 100nm. We observed elevated concentrations of tungsten, which was most likely due to electrode consumption. Mean ROS production potential of TIG welding fumes at the BZ exceeded average concentrations previously found in traffic-polluted air. Furthermore, ROS production potential was significantly higher for apprentices that burned their metal during their welding task. We recommend that future exposure assessments take into consideration welding performance as a potential exposure modifier for apprentice welders or welders with minimal training.
authors.affiliation: 1.Institute for Work and Health, University of Lausanne and Geneva, 1066 Epalinges-Lausanne, Switzerland;
authors.forename: Halshka
authors.initials: H
authors.lastname: Graczyk
authors.affiliation: 1.Institute for Work and Health, University of Lausanne and Geneva, 1066 Epalinges-Lausanne, Switzerland; 2.Department of Chemical and Life Science Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA;
authors.forename: Nastassja
authors.initials: N
authors.lastname: Lewinski
authors.affiliation: 1.Institute for Work and Health, University of Lausanne and Geneva, 1066 Epalinges-Lausanne, Switzerland;
authors.forename: Jiayuan
authors.initials: J
authors.lastname: Zhao
authors.affiliation: 1.Institute for Work and Health, University of Lausanne and Geneva, 1066 Epalinges-Lausanne, Switzerland;
authors.forename: Nicolas
authors.initials: N
authors.lastname: Concha-Lozano
authors.affiliation: 1.Institute for Work and Health, University of Lausanne and Geneva, 1066 Epalinges-Lausanne, Switzerland; 3.SAFENANO, IOM Singapore, Singapore 048622 michael.riediker@alumni.ethz.ch.
authors.forename: Michael
authors.initials: M
authors.lastname: Riediker
mesh_terms: D000395:Air Pollutants, Occupational / Q000032:analysis; D005740:Gases / Q000032:analysis*; D006801:Humans; D019570:Inhalation Exposure / Q000032:analysis; D008297:Male; D008670:Metals; D053758:Nanoparticles / Q000032:analysis; D016273:Occupational Exposure / Q000032:analysis*; D010316:Particle Size; D014414:Tungsten / Q000032:analysis*; D014896:Welding / Q000295:instrumentation / Q000379:methods
chemical_list: D000395:Air Pollutants, Occupational; D005740:Gases; D008670:Metals; D014414:Tungsten
keywords: PM4; gas metal arc welding (GTAW); nanoparticles; occupational exposure; tungsten inert gas (TIG); welding fumes; workplace air