Environmental epidemiology
Environmental epidemiology is the branch of epidemiology concerned with the discovery of the environmental exposures that contribute to or protect against injuries, illnesses, developmental conditions, disabilities, and deaths; and identification of public health and health care actions to manage the risks associated with harmful exposures. Environmental epidemiology studies external factors that affect the incidence, prevalence, and geographic range of health conditions. These factors may be naturally occurring or may be introduced into environments where people live, work, and play. Environmental exposures are involuntary and thus generally exclude occupational exposures and voluntary exposures such as active smoking, medications, and diet.