Sustainable aviation fuels (SAFs) are currently considered a key element in the decarbonization of the aviation sector, offering a feasible solution to reduce life cycle greenhouse gas emissions without requiring fundamental changes in aircraft or infrastructure. This article provides a comprehensive overview of the current state of SAFs, including their classification, production technologies, economic aspects, and environmental performance. The analysis covers both currently certified SAF pathways, such as HEFA and FT-SPK, and emerging technologies like alcohol-to-jet and power-to-liquid, assessing their technological maturity, feedstock availability, and scalability. Economic challenges related to high production costs, investment risks, and policy dependencies are discussed, alongside potential mechanisms to support market deployment. Furthermore, the article reviews SAFs’ emission performance, including CO₂ and non-CO₂ effects, based on existing life cycle assessment (LCA) studies, with an emphasis on variability caused by feedstock type and production method. The findings highlight that, while SAFs can significantly reduce aviation-related emissions compared to fossil jet fuels, the magnitude of benefits depends strongly on supply chain design and sustainability criteria. There are various certified pathways for SAF production, as well as new technologies that can further contribute to the development of the industry. Properly selected biomass sources and production technologies can reduce greenhouse gas emissions by more than 70% compared to conventional fuels. The implementation of SAFs faces obstacles related to cost, infrastructure, and regulations, which hinder its widespread adoption. The study concludes that although SAFs represent a promising pathway for aviation climate mitigation, substantial scaling efforts, regulatory support, and continued technological innovation are essential to achieve their full potential.

The paper analyzes the exhaust emissions from farm vehicles based on research performed under field conditions (RDE) according to the NTE procedure. This analysis has shown that it is hard to meet the NTE requirements under field conditions (engine operation in the NTE zone for at least 30 seconds). Due to a very high variability of the engine conditions, the share of a valid number of NTE windows in the field test is small throughout the entire test. For this reason, a modification of the measurement and exhaust emissions calculation methodology has been proposed for farm vehicles of the NRMM group. A test has been developed composed of the following phases: trip to the operation site (paved roads) and field operations (including u-turns and maneuvering). The range of the operation time share in individual test phases has been determined. A change in the method of calculating the real exhaust emissions has also been implemented in relation to the NTE procedure.

The quality of outdoor air in many places, especially in urbanized areas, is bad; therefore, a series of studies aimed at assessing the impact of outdoor air parameters on indoor air quality was conducted. Four nurseries (three buildings) located in different parts of Poznań, Poland were selected as research sites. During the research period, the concentrations of CO₂, PM2.5, and PM10 inside and outside the buildings over time were analyzed. Measurements outside the buildings were supplemented with an analysis of traffic near nurseries and an assessment of pollutant emissions from vehicles of various categories. Measurements were conducted during the COVID-19 pandemic in a weekly series during winter (December)—(W), spring (April)—(S), and at the end of spring (June)—(LS). Testing and analyses indicated poor indoor air quality in three out of four nurseries. To ensure indoor air quality at the proper level, it is necessary to supply rooms with outside air. Ventilating rooms by airing, when the outside air is polluted, reduces the CO₂ concentration but worsens the indoor air quality in terms of particulate matter (PM). Seasonality in the concentration of particulate matter in outdoor air and its connection with the outside air temperature was noticed. No relationship between traffic and the values of PM10 and CO₂ concentrations inside nurseries was observed.

The subject of this article was the analysis of the current state of legislation regarding the exhaust emissions from two-wheeled vehicles. The regulations and emission limits were analyzed and compared for different areas of the world. Moreover, the review of the legal provisions includes an individual approach to specific categories of two-wheeled vehicles. The study also describes the research and exhaust emission measurement methods from mopeds and motorcycles both under laboratory conditions and in actual operation. The methods were evaluated in the aspect of future emission requirements and trends. In addition, the results of emissivity measurements under actual operating conditions obtained in the Poznan agglomeration with the use of motorcycle units were discussed and analyzed. The values of mad emissions of all toxic compounds limited by legislators were compared with emission standards.

The paper evaluates particulate matter emissions and exhaust gas components from retrofitted engines of non-road vehicles measured under actual operating conditions. The content is divided into three main parts: formation of guidelines, production of the filter and emission tests. The obtained results clearly indicate excess PM and PN emissions from the engine under actual operating conditions when compared to the limits outlined in the type approval standards. Moreover, it was observed that the actual conditions are reflected to a very small extent at the points included in the stationary homologation test cycle. Based on these observations, the authors decided to modify the stationary test cycle. The measured exhaust gas compositions and their mass flow rates were used to create the geometry of the newly developed filter. The paper contains detailed results of the relative specific exhaust emissions of particulate matter and gaseous components at individual engine operating points. The exhaust emissions analysis made it possible to draw conclusions regarding the operation of the newly designed system. One of them is that fitting a metal-support particulate filter in the exhaust system significantly contributes to reducing the exhaust emissions.

In September 2017, the EURO 6c homologation standard was introduced for PC class vehicles. It presents the RDE test, i.e. the procedure for testing toxic emissions in real operation conditions and restrictions regarding particulate emissions in the number range for engines with direct gasoline injection. This article presents the results of simulations of the exhaust gases flow through a ceramic carrier placed in the exhaust system of the engine with direct fuel injection. The AVL Fire Aftertreatment software was used for the simulation of non-engine CI and SI exhaust gas systems. The introduced concentrations of specific harmful compounds were selected on the basis of previous tests in real operating conditions in the urban cycle. This cycle was chosen because of its association with the lowest exhaust gas temperature. As part of the article, the exhaust gases flow through the filter, whose volume was selected on the basis of the displacement volume of a turbocharged combustion engine, was examined. The filter cannot have a large diameter because the exhaust gases flow is not carried out with its entire surface. These assumptions were dictated by problems with regeneration of diesel particulate filters in low-temperature exhaust gases. The variable was primarily the temperature of the exhaust gases and the carrier itself, the number of cells per square inch (200 CPSI) was constant.