Hubert Kuszewski

The problem of poor air quality in urban areas has a negative impact on the health of residents. This is especially important during periods of smog. In Poland, as in other countries, the problem of poor air quality, especially during the winter season, is associated with a high concentration of particulate pollutants in ambient air (PM10, PM2.5). Sources of particulate emissions, in addition to solid-fuel boilers, include means of transportation, especially those equipped with diesel engines. In turn, during periods of strong sunshine (spring and summer), the problem of photochemical smog, whose precursors are nitrogen oxides NOX, arises in urban areas. Their main sources of emissions are internal combustion engines. Therefore, to improve air quality in urban areas, changes are being made in the transport sector, among which is upgrading the fleet of urban transport vehicles to low- or zero-emission vehicles, which are more environmentally friendly. In addition, measures that reduce the harmfulness of the transportation sector to air quality include the introduction of clean transportation zones, as well as park-and-ride (P&R) systems. The purpose of this article is to present the results in terms of PM10, PM2.5, and NOx emission reductions, implemented over a period of two years (2021–2022) in the area of the Rzeszow agglomeration, related to the modernization of the suburban bus fleet and the implementation of a P&R system for passenger cars. The results of the study were compared with the value of estimated emissions from coal-fired boilers used for residential heating and hot water, which also contribute to smog. Thanks to the implementation of the project, i.e., the replacement of 52 old buses with new buses of the Euro VI emission class and the construction of new P&R spaces, the total average annual reduction in emissions amounted to approximately 703.6 kg of PM10, approximately 692.7 kg of PM2.5, and a reduction of approximately 10.4 tons of NOX.

This article presents the results of an assessment of the combustion process of blends of n-hexane and canola oil. Tests were conducted for pure canola oil and its blends with n-hexane, with a max. n-hexane content of 20% by volume. The tests were carried out using the constant volume combustion chamber (CVCC) method as well as a diesel engine. For comparison purposes, the results for typical diesel fuel are also presented. Tests on the self-ignition properties of the n-hexane–canola oil blend, conducted in a CVCC according to the normative method for diesel fuel, showed little effect on the combustion process. However, previous tests conducted on a diesel engine of a passenger car showed a favorable effect of the n-hexane addition to canola oil on the combustion process in the engine, the performance and environmental parameters obtained. This shows that for some fuels, the evaluation of self-ignition and combustion properties in a constant volume combustion chamber, under conditions corresponding to diesel fuel tests, is not sufficient. The findings of this research may be beneficial in optimizing the diesel engine combustion systems fueled by renewable fuels. As the results of the tests have shown, the standardized method for determining the combustion process of the CVCC method does not always fully reflect the results obtained in engine tests. The results obtained by the CVCC method can be successfully used when comparing fuels, but when considering the selection of fuel for the engine, the results obtained in engine tests should be relied on first and foremost.