This study is focused on the characterization of particles emitted in the metal active gas
welding of carbon steel using mixture of Ar + CO2, and intends to analyze which are the main
process parameters that influence the emission itself. It was found that the amount of emitted
particles (measured by particle number and alveolar deposited surface area) are clearly
dependent on the distance to the welding front and also on the main welding parameters,
namely the current intensity and heat input in the welding process. The emission of airborne
fine particles seems to increase with the current intensity as fume-formation rate does. When
comparing the tested gas mixtures, higher emissions are observed for more oxidant mixtures,
that is, mixtures with higher CO2 content, which result in higher arc stability. These mixtures
originate higher concentrations of fine particles (as measured by number of particles by cm3 of
air) and higher values of alveolar deposited surface area of particles, thus resulting in a more
severe worker’s exposure.