Background. The greatest threat to human health is provided by the suspended particular mater with an aerodynamic diameter of 10 μm or less. Since they can lead to an increase of frequency of respiratory and cardiovascular diseases and contribute to an increase in mortality from these diseases.

Objective. The research was aimed to carrying out a hygienic assessment of the particular mater content of the PM₄ and PM₁₀ fraction in the atmospheric air and in the air of the working area of the metallurgical enterprises.

Methods. It was performed the 3000 studies of PM₄ and PM₁₀ concentrations in the atmospheric air and 1838 - at workplaces. The study was carried out using a piezo-balanced measuring instrument for mass concentration of respirable dust - KANOMAX 3521.

Results. It was found that the maximum one-time concentrations of PM₁₀ in the ambient air exceeded permissible concentration 20-minute mean only in sporadic cases, but daily average concentrations of these substances systematically exceeded recommended levels. It was established that the content of PM₄ and PM₁₀in the air of the working area in the agglomeration department, in the blast furnace guild, in the open-hearth guild mater and in the mechanical guild of metallurgical production significantly higher than in the control area.

Conclusion. Organization of constant continuous monitoring of PM content in the air is a prerequisite for a correct assessment of their impact on the health of the population and workers.

KEY WORDS: particular mater, PM_2.5, PM₁₀, atmospheric air, working air, nanoparticles.