Air quality and particles · Epidemiological(流行病学) evidence associates atmospheric particles with diseases and mortality Particles penetrate the lungs, blocking and irritating air passages. Particles themselves could exert toxic effects. (toxic substances present in the particles) [polycyclic Aromatic Hydrocarbons are examples of toxic substances in aerosols.Air quality and particles • Epidemiological (流行病学) evidence associates atmospheric particles with diseases and mortality. – Particles penetrate the lungs, blocking and irritating air passages. – Particles themselves could exert toxic effects. (toxic substances present in the particles) [Polycyclic Aromatic Hydrocarbons are examples of toxic substances in aerosols.]