Exhaust emissions from vehicles are the subject of numerous studies and legal acts. In the European Union, exhaust emissions are regulated by “Euro” emission standards, which limit emissions of gaseous pollutants such as CO, CO₂, HC, and NOx, as well as the particulate matter (PM) and particle number (PN). Solid particles consist of a number of micro-contaminants, inter alia polycyclic aromatic hydrocarbons (PAHs) and their nitrated and oxygenated derivatives. Despite their highly mutagenic and carcinogenic character, these micro-contaminants are not regulated in Euro emissions standards. This paper presents both a general discussion of the phenomenon of particulate formation in and emission from direct injection gasoline engines, as well as a wide range of results on the subject. The subject of the micro-contaminants in solid particles from modern gasoline vehicles is explored. The samples of solid particles were collected from 11 groups of vehicles according to the WLTP test methodology. Solid particles from gasoline vehicles were analyzed via various analytical techniques, including ion chromatography (IC) to measure selected anion concentrations, gas chromatography with mass spectroscopy (GC-MS) to study 16 PAHs and selected PAH derivatives, scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS) for images and elemental composition, and microwave plasma atomic emission spectroscopy (MP-AES) for qualitative screening analysis of 19 elements. The study of non-regulated compounds is crucial in efforts to establish the influence of solid particles on health and the environment. Furthermore, extended studies can provide a basis for further research on vehicle emissions or other fields, such as medicine or material engineering.

The most common methods of reducing mercury emissions are the use of fixed bed granular sorbents and sorbent injection. However, both of these methods have disadvantages, such as increasing the flow resistance or the need to remove the sorbent from flue gas, respectively. These disadvantages can be eliminated by using sorbents permanently bound to construction materials (fixed sorbent materials—FSMs) or mixed with construction materials (sorbent polymer composites—SPCs). The approach is unique in the world literature as well as the development of three stands and procedures enabling the testing of FSMs or SPC materials based on Tarflen as a construction material. In order to further tests of FSMs and SPCs, the system for laboratory tests and two systems for industrial tests are developed. These stands and procedures enable determination of the influence of: FSM or SPC module shapes, flue gas properties (e.g., composition, temperature, flow rate), and mercury concentration on the effectiveness of mercury removal by SPCs and FSMs. In this paper, the influence of module shapes, gas velocity, and temperature is particularly considered. In the final industrial tests, the FSM removes 99.5% Hg after 42 days and the SPC removes from 99.5% to 82.3% after 34 days.

The awareness of environmental pollution has been continuously growing in recent decades and is currently reaching its maximum. Europe and most developed countries are determined to ensure safe breathing air for their citizens, and the measures to do so are stricter than ever before. Combustion procedures remain the primary means of producing energy and warmth in Poland. Among the notable constituents of flue gases produced as a result of fuel combustion, solid particles (or particulate matter) hold significant prominence. The paper presents the chemical characterisation of particulate matter emitted from stationary and automotive emission sources. Stationary emission sources included the combustion process of fossil fuels (soft wood, bituminous coal, ecopea coal, culm) in domestic heating units and the process of combustion of bituminous coal in a power plant. Automotive emission sources included light duty and medium duty vehicles fuelled by diesel. Exhaust toxicity tests were carried out maintaining the real conditions of PM emission. In all field measurements particulate matter was gravimetrically measured and collected on quartz or glass fibre filters. Subsequently, the content of carbonaceous fraction, inorganic ions, and metals and metalloids was analyzed using different analytical techniques. The chemical composition of the particulate matter differed depending on the emission source. With respect to stationary combustion sources, the main factors determining solid particle emission are related primarily to the fuel quality. The duty of vehicles was also a factor that influenced the chemical characterisation of the particulate matter emitted from the engines.

In this study, we designed a prototype reactor, the multiple pipes reactor (MPR), for Hg(0) capture, which can be applied in small-scale boilers. It was tested on a laboratory scale by comparing it with a fixed-bed type, the vertical glass reactor (VGR). In total, 200 mg of CuO and CuS was applied as sorbent materials to reduce the concentration of Hg(0) from the simulated flue gas, in both VGR and MPR reactors. The mercury capture measurements were performed in the same laboratory system at 125 °C and a flow rate of 54 L/h. The contact time between the sorbents and simulated flue gas in the VGR was 0.035 s for both materials. In the case of the MPR, it was 0.44 s (CuO coating) and 0.63 s (CuS coating), depending on the coating area. The contact area inside the VGR was 5.31 cm², contrasting with the values of 13.19 cm² (CuO coating) and 18.84 cm² (CuS coating) in the MPRs. The average Hg(0) capture effectiveness of CuO (granulate) and CuS (granulate) was 51% and 67% in VGR, respectively. The MPR with CuO- and CuS-coating Teflon (PTFE) pipes promoted an average Hg(0) capture effectiveness reaching 65 (by 268%) and 94% (by 158%), respectively.

Mercury is a highly toxic metal which naturally occurs in the Earth’s crust and has adverse effects on both humans and the environment. The use of fossil fuels for electricity generation and specific industries sources of mercury emissions. These emissions depend on the mercury content in fuels of different types, the process gas temperature and composition, the implementation of air pollutant control devices (APCDs), etc. The APCDs partially capture and/or oxidize mercury in flue gas as a side benefit. In some cases, the emissions are reduced by mercury-dedicated or mixed methods. Mercury transformation in process gases is generally based on a chain of homogeneous and/or heterogeneous reactions. The theory of gaseous mercury/solid phase reactions and its mechanisms is widely studied in the literature. In this review, we focused on the theoretical and practical studies of these mechanisms, including mercury oxidization and capture from specified laboratory simulated or process gases and industries. We summarized research on various reactions – mostly of a chemical type – between different forms of mercury derived from process gases, and solids, including particles of different kinds (fly ash, adsorbents or catalysts). We additionally reviewed the literature on the interactions between mercury and sulfur compounds in the simulated and process gases.