• Mixture of airborne particles and gasses released or produced by the welding process
• Composition varies according to the welding process and typically contains metal oxides and other metal reaction products, particulate from flux of electrodes and gases produced by UV light like ozone and shielding gases
• Finer dust mass fraction is alveolic and can accumulate in the lungs and remain in the body
• Compounds. 90% of the particles come from the welding consumables