Objectives The purpose of the research is the study of dust fractional and chemical composition and exposure assessment in workplaces of the machine building enterprises.

Methods Research carried out on the example of one of the largest machine building enterprise of Perm. Sampling was carried out at the workplaces, directly at the emission sources. Dusts fractional composition was determined using a laser particle analyser Microtrac S3500 (covering the particle size range from 20 nm to 2000 microns). Based on the determinated fractional composition was the mass concentration of TSP calculated, and then the mass of PM2.5 and PM10. Dusts microscopy was conducted using a scanning electron microscope with high resolution X-ray fluorescence attachment S3400N «HITACHI».

Results The results showed that the composition of the dust emissions in different technological processes is heterogeneous. In workplace air of welders, turners, millers the PM10 fraction reaches 2 - 50%, PM2.5 - 1 - 13%. Median diameters size: 50–300 mkm. By microscopy of dust from welding in carbon dioxide were identified nanoscale dust particles. Dust contains iron oxides, manganese, chrome, vanadium and fluoride compounds, while also established the presence of silicon, carbon, sodium, magnesium, aluminium, calcium.

Conclusions

• - dust pollution workplace air for welders, turners, millers and the other employees characterised by high proportion of fine particles, indicating the threat to health of employees;

• - for some technological processesestablished presence of the nanoparticles in the dusts of the work area air. Hygienic characteristics of the nanoparticles are poorly understood, that requires close attention to the quality of the working area air when performing technological operations;

• - the results confirm the relevance of the determination of fractional and chemical composition of dust in the workplaces air pollution. Such data will allow to evaluate the employees personal exposure and hygienic characteristics of working conditions correctly.