Urban ozone and its precursors

Many regions have not attained the Natl Ambient Air Quality Standard (NAAQS) for ozone by the December 1987 deadline. EPA estimates that at least 60 major metropolitan areas will be out of compliance. The O sub(3) problems of urban areas are considered, emphasizing three important issues. The first concerns the form and level of the NAAQS, which directly affects the achievability of the standard as well as confidence in attainment. The second issue encompasses the trend in O sub(3) concentrations, which is a measure of the effectiveness of existing control schemes. The last concerns the control strategies whose failures may reflect a deficiency in the comprehension of the O sub(3) problem or in the implementation of the strategies themselves. Reliable measurements and robust statistics are prerequisites for more effective O sub(3) control.