Core Description: This Core will operate the exposure systems developed at National Jewish for the short-term exposures of cultured cells and rodents to physiologically relevant levels of ozone. In addition, the Core will respond to investigator requests for alterations of the systems to meet specific experimental requirements (e;g., ramping of ozone concentrations, correction of ozone concentration for altitude dilution effects, rocking of cultured cells). An important function of the Core will be to ensure that the ozone is confined to the experimental apparatus, thereby not endangering laboratory personnel. The Core also maintains the computerized data acquisition systems associated with the exposure units and modifies the internally written programs to meet invesfigator needs.