This document analyses literature studies on sources of ultrafine particles (diameter less than 100 nm) indoors and outdoors. Information is provided on relevant emission factors, particle concentrations, sizes and compositions, and the health relevance of ultrafine particles and particulate matter is discussed. Method used a PRISMA review methodology of articles over the last 20 years and treatment with IraMuTeq was carried out. The results show that inhalation exposure to fine and ultrafine particles is associated with respiratory diseases. However, little is known about the quality, thresholds and concentrations of these particles that cause adverse health effects. Exposure to UFP in the environment and workplace is known to cause adverse health effects. However, little is known about how these aerosols trigger the development of pathophysiological mechanisms in the body or how ultrafine particles behave in the lung after inhalation. It is important to study the issue in depth, as little is known about the consequences and problems triggered. It is also extremely important to set exposure limits to protect population.