"INTRODUCTION This report describes the work performed by Scott Research Laboratories@ Inc. on APRAC Project No@ CAPA-7-68@ ""Atmospheric Reaction Studies in the Los Angeles Basin"" (Contract No. CPA 70-6). This project was sponsored jointly by the National Air Pollution Control Administration and the Coordinating Research Council@ Inc. This report is contained in four volumes. Volume I includes a complete description of the study methodology as well as a thorough representation of the quantitative and qualitative results obtained. Volumes II@ III and IV contain all of the relevant data which were collected in the test operations displayed as 10 minute averages for ground data and by altitude for vertical profiles@"