Microstructural analysis of liquefied petroleum gas vehicle emissions, one of the anthropogenic environmental pollutants

Human health and a clean environment are undoubtedly of great importance all over the world. Currently, toxic exhaust emissions in the atmosphere are significantly increasing due to the more widespread use of motor vehicles. In this study, we aimed to characterize the microstructure and chemical properties of exhaust particles released from modified spark-ignition vehicles powered by liquefied petroleum gas fuel. For this purpose, particulate matter samples taken from vehicle exhausts in Karaman, Turkey, were analyzed via scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction spectroscopy and Fourier-transform infrared spectroscopy. Microscopic studies of these particles showed the particulate matter to have an ultra-thin (150-nm) nanostructure, whereas the energy-dispersive X-ray spectroscopy studies identified 18 element structures in the content, including carbon, oxygen and nitrogen. In addition, the morphology and crystallography of toxic structures such as hydrocarbons, nitrogen oxides, sulfur oxides and carbon dioxide were determined by the X-ray diffraction spectroscopy, and molecular bonds were revealed by the Fourier-transform infrared spectroscopy. Our results demonstrated that the exhaust emissions of all vehicles using petroleum-derived fuel contained harmful components at levels above those acceptable for environmental and human health. In addition, vehicles using liquefied petroleum gas as fuel produced relatively fewer harmful emissions compared to other vehicles. However, due to the low cost of liquefied petroleum gas, the more widespread use of these vehicles also significantly increases the amount of exhaust emissions, uncontrollably spreading pollutants into the atmosphere and causing environmental problems.