Study on welding fume particles of gas shielded welding in workplaces

  Objective  To study the exposure characteristics of welding fume of gas shielded welding in workplaces, and to provide basic data for health risk assessment and control of welding fume particles in workplaces.

  Methods  In the experimental test space, the welding process was simulated. The particle size distribution, particle number concentration and mass concentration of the welding fume were detected at the welding personnel's working positions and the auxiliary welding positions(50 cm and 250 cm away from the welding source). Meanwhile, the particle size sampling was carried out to analyze the content and distribution of metal elements in the fume.

  Results  During 150 s of welding, the average concentration of particles detected at 50 cm away from the welding source was(72.50±16.55)×10⁵ particles/cm³, of which about 60% were ultrafine particles(particle diameter < 100 nm). Once the welding stopped, the number concentration of particles decreased significantly(P < 0.01), especially the ultrafine particles. The number concentration of particles in 50 nm, 100 nm and 1 000 nm diameter channels decreased by 94.45%, 78.93% and 50.63%, respectively. During welding, the number concentration and mass concentration of particles detected at 250 cm away from the welding source were significantly higher than the background value(P < 0.01), which were 45.84 times and 2.9 times of the background value, respectively, and the highest number concentration was(20.47±5.91)×10⁵/cm³, but it was lower than the concentration at 50 cm(P < 0.01). The mass concentration of metal elements in welding fume with particle size of 0.32 - 0.56 μm reached the peak, and the mass fraction of ultrafine particles was 10.06% of the total metal elements.

  Conclusions  A large number of ultra-fine particles were produced in welding operation; welding fume metals and their compounds were mainly distributed in fine particles and ultra-fine welding fume, which may have a higher potential toxicity. The local ventilation and personal protection should be strengthened in workplaces, and the protection and monitoring of welding operators and auxiliary workers should be strengthened.