Air pollution is a change in the quality and purity of the air caused by natural or anthropogenic chemical and biological substance emissions. It is the most significant environmental factor affecting respiratory health in Europe. Inhalable particles are among the pollutants that impair air quality. Simply expressed, inhalable particles have an aerodynamic diameter of less than 10 µm (PM 10), small inhalable particles have an aerodynamic diameter of less than 2.5 µm (PM 2.5), and coarse inhalable particles have an aerodynamic diameter of between 2.5 µm and 10 µm.The risk that exposure to this agent poses to human health is determined by the particle size, as well as the surface and chemical makeup of the particulate material. Fine particles penetrate deeply into the respiratory system and may disrupt the alveoli due to their tiny size. Air pollutants have these effects through triggering intracellular signalling pathways and transcription factors that are known to be vulnerable to oxidative stress, or by causing direct cellular injury.