A summary is presented of the results of a comprehensive air pollution study conducted by the Los Angeles County Air Pollution Control District (LACAPCD) under contract with the Air Pollution Control Office of the Environmental Protection Agency. Included in the data obtained are the results of exhaust testing, emission estimates of aircraft and airport ground operations, measurements of the atmosphere in the immediate environs of the airport, and passenger cabin measurements. The data indicate that the CO emissions from airport ground operations exceed levels generally attributed to commercial jet aircraft. Passenger cabin CO measurements during startup and taxiing procedures indicate average levels of 2-7 ppm. Air quality levels in the residential areas around the airport indicate average 6 hr CO concentrations of 3-11 ppm.