Gasoline particles are microscopic solid and liquid aerosols produced during the combustion process in gasoline engines, especially in modern gasoline direct-injection (GDI) systems. Unlike traditional port-fuel injection engines, GDI engines spray fuel directly into the combustion chamber, creating localized fuel-rich zones that burn incompletely and generate particulate matter. These particles include soot, organic carbon fragments, unburned hydrocarbons, metallic residues from engine wear, and ultrafine nanoparticles capable of penetrating deep into the human respiratory system. Their formation is influenced by fuel composition, air–fuel mixing, combustion temperature, and engine condition. Aromatic hydrocarbons and poor fuel atomization significantly increase particle formation, while ethanol blends and cleaner fuels help reduce it. To control particulate emissions, gasoline particulate filters (GPFs) have become standard in many modern engines. These ceramic honeycomb filters trap soot through porous walls and soot-cake buildup. They regenerate automatically through oxidation at high exhaust temperatures, or with catalytic coatings that enable soot burn-off at lower temperatures. Three-way catalytic converters still reduce hydrocarbons and nitrogen oxides, but GPFs are essential for meeting strict particle-number emission regulations. Engine-based solutions—such as high-pressure injectors, better combustion chamber design, optimized injection timing, and improved thermal management—further reduce particulate formation. Fuel quality, including low-aromatic gasoline and ethanol blending, plays an equally important role. Gasoline particulate emissions have serious health impacts, contributing to respiratory diseases, cardiovascular problems, and inflammation. Ultrafine particles can enter the bloodstream and deposit in organs, while metal nanoparticles may cause oxidative stress. Environmental impacts include atmospheric warming, smog formation, and long-range pollutant transport. Reducing gasoline particulate emissions through filtration, cleaner fuels, and improved engine technologies is therefore critical for public health, environmental protection, and compliance with global emission standards.