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.]
This version is made for bilingual teaching .Case-control study is an essential research design of Epidemiology, which involves identifying patients who have the outcome of interest (cases) and control patients who do not have that same outcome, and looking back to see if they had the exposure of interest. The exposure could be some environmental factor, a behavioural factor, or exposure to a drug or other therapeutic intervention