Hygienic substantiation of the hazard classification of substances polluting the atmospheric air, taking into account the «offensiveness» of their odour

Introduction. Expansion of approaches to assessing the odour of substances polluting the atmospheric air, with the introduction of odorimetry (measuring the strength, intensity of odour) into practice indicates that the existing classification of the olfactory hazard of odorous components according to the “undefined” odour needs to be updated.

Materials and methods. Experimental studies with the definition of a quantitative expression of the dependence of the likelihood of odour detection of different strengths on the concentration were carried out using the example of 13 mixtures of volatile organic substances on a dynamic olfactometer. The volume of olfacto-odorimetric studies was over 4600 measurements. Statistical data analysis was performed using the Probit Analysis computer program (v.4.0).

Results. Based on the studies carried out, it was found that the lower the ratio of the concentration causing a 5% probability of detection of odour with a strength of 3 points (threshold of “offensiveness”, Lim_off.) to the concentration causing a 50% probability of “undefined” odour (detection threshold or the threshold for an “indeterminate” odour, Lim_indef.), the more dangerous the substance is in relation to the development of an “offensive” odour. A new classification of the hazard of substances is proposed, taking into account the “offensiveness” of their odour: extremely offensive (Lim_off./Lim_indef. ≤1.5), offensive (Lim_off./Lim_indef. ≤3), moderately offensive (Lim_off./Lim_indef. ≤6), slightly offensive (Lim_off./Lim_indef. > 6).

Limitations. This study is not without certain limitations, among which the main ones are the use of a relatively new method that requires additional testing; a relatively small number of study participants; methods for presenting odor stimuli and registering them.

Conclusion. The ability of odorous substances to cause a feeling of “offensiveness” (“annoyance potential”), and, accordingly, their hazard class depends on the characteristics of the spectra of graph dependences of the probability of different strengths odour on the concentration on the probabilistic grid and the ratio of the parameters of the resulting dependencies.