Objective To understand the hazard status and the influencing factors of welding fumes and silica dust by active monitoring in Qingpu District of Shanghai, and to provide a scientific basis to intervene the hazards of welding fumes and silica dust．
Methods A total of 68 welding workstations from 20 enterprises involving welding operation and 106 silica dust workstations from 30 enterprises with silica dust exposure were randomly selected to investigate. The workplace airborne dust was collected using personal air sampler and detected by weighing method to analyze disqualified air dust rates and associated influencing factors.
Results The median concentration of welding fumes was 2.95 (P25=1.23,P75=8.55) mg/m3, and that of silica dust was 3.35 (P25=1.06,P75=6.46) mg/m3. The dust concentrations in 74.00% enterprises exceeded relevant national standards, with a disqualified rate of 70.11% for sampled workstations. Especially, the concentrations of welding fumes in 50.00% enterprises with welding operation were disqualified, with a disqualified rate of 42.65% for sampled workstations; the concentrations of silica dust in 90.00% enterprises with silica dust exposure were disqualified, with a disqualified rate of 87.74% for sampled workstations. Job characteristics (P=0.007) and welding types (P=0.006) were the major factors affecting welding fume concentrations, whereas operating environment characteristics (P=0.000) and working time (P=0.001) were the major factors affecting silica dust concentrations.
Conclusion Serious hazard status of welding fumes and silica dust are identified in Qingpu District. Welding types and operating time are the main influencing factors of welding fumes to intervene. Efforts should be made to improve working environment characteristics and reduce operating time to intervene the hazards of silica dust.
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