Hygienic characteristics of the atmospheric air in the area of the intensive use of the road-car complex

Introduction. The level of air pollution in the areas of traffic flows is influenced by fuel combustion processes. Among air pollutants, special attention should be paid to methane. Methane is formed during the combustion of liquid fuels and is a precursor of formaldehyde. Formaldehyde is synthesized in the presence of catalysts. Its concentration exceeded the maximum permissible limits.

The aim of the study is the hygienic assessment of additional aerogenic risk to public health due to formaldehyde, formed during the operation of the road-car complex (RCC).

Material and methods. The calculation of the amount of methane entering the air during the operation of vehicles from fuel combustion is determined in accordance with the EMEP/EEA emission inventory Manual (2016).) The concentration of the studied pollutants is determined in accordance with the Order No. 273 of 06.062017 «Methods of calculation of dispersion of emissions of harmful (polluting) substances in the air». RCC is classified according to the intensity of traffic from 500 to 7,000 vehicles per hour. Risk calculation was carried out on the basis of guidance 2.1.10.1920-04 «Guidelines for assessing the risk to public health when exposed to chemicals that pollute the environment». The concentration of formaldehyde in ambient determined in accordance with the methodical instruction 4.1.1272-03. Statistical analysis was carried out using the Excel 2016 application package.

Results. Methane (CH4) emission factors (mg/km), presented in the EMEP/EEA Manual, allowed determining the amount of methane emission (mg/s) per 1 km at different traffic intensities (auth./hour.) The obtained data were used to calculate the model concentrations of formaldehyde synthesized from methane. The calculated model concentrations were used to calculate additional carcinogenic and non-carcinogenic risk due to formaldehyde.

Сonclusions. The gain in motorization of the population is accompanied by an increase in air pollution in the zone of influence of road transport. However, the emission inventory does not take into account the possible transformation of the pollutants making up the exhaust gases. Incomplete information does not allow using them to predict health risk levels based on model concentrations. The results obtained allowed obtaining information about the amount of additional carcinogenic and non-carcinogenic risks created in the process of transformation of methane into formaldehyde. The most unfavorable temperature regime (0-15oC) contributing to the synthesis and slowing down the decay of formaldehyde in the atmosphere along the roads was revealed.