Introduction. The use of new air protection technologies for cleaning industrial emissions requires a comprehensive hygienic assessment, including an analysis of not only the effectiveness of reducing concentrations of regulated pollutants, but also the possible formation of products of their transformation, which may have different physico-chemical and toxicological properties.

Materials and Methods. Organic substances were conducted in the air of production rooms using a chromatographic-mass-spectrometric method at the inlet and outlet of the biofilter, and at the border of the sanitary protection zone of a pet food factory in Stupino, the Moscow Region.

Results. In the air of production premises, one hundred fourteen organic compounds were identified, mainly oxygen-containing compounds (83–97% of the total). At the inlet of the biofilter, 45 compounds were identified with a total concentration of 4.328 mg/m³, and at the outlet, 71 compound were identified with a concentration of 3.558 mg/m³. There was a 5.7-fold decrease in the concentration of alcohols, a 1.4-fold decrease in the concentration of aldehydes, and a 1.9-fold decrease in the concentration of ketones. However, there was a 1.5-fold increase in the concentration of phenols and the appearance of 26 new compounds, including unsaturated hydrocarbons, esters, 1,4-dioxane, nitromethane, and microbial metabolites. At the SPZ border, 40 compounds were identified with a total concentration of 0.146 mg/m³, which did not exceed the hygienic standards. For 33% of the compounds detected at the SPZ border, no hygienic standards have been established. Technology can be considered safe.

Limitations. The study is limited to the use of a method for studying organic compounds with molecular formulas C5–C20, which does not allow for the assessment of the contribution of more volatile and hardly-volatile components.

Conclusion. Biofiltration reduces the total content of organic pollutants in feed production emissions, but it also involves the transformation of initial substances and the emission of microbial metabolism products. To assess the hygienic safety of environmental technologies, it is necessary to analyze the trend in the complete component composition of pollutants at all stages of treatment. Compounds identified at the SPZ boundary that do not have regulatory requirements require additional study to justify the priority of their control.

Compliance with ethical standards. This study does not require approval by the local ethical committee

Contribution: Malysheva A.G. – research concept and design, text writing, data collection and processing, editing; Ushakova O.V. – data processing, text writing, editing; Starodubova N.Yu. – data processing, text editing; Evseeva I.S. – text writing, editing. All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.

Conflict of interest. The authors declare no conflict of interest.

Funding. The study had no sponsorship.

Received: October 16, 2025 / Revised: April 7, 2026 / Accepted: May 20, 2026 / Published: June 18, 2026