Ozone and Particulate Matter Case Study Analyses for the Southern California Air Quality Study

摘要

As part of the Southern California Air Quality Study (SCAQS), case study analyses of the surface and aloft air quality data for three SCAQS episodes were undertaken to improve the authors understanding of the evolution and sources of ozone and particulate matter concentrations in the South Coast Air Basin (SoCAB), the formation mechanisms of aloft polutant layers, the importance of these aloft layers to surface concentrations, and to recommend how these phenomena and species distributions should be modeled. The report summarizes the data analyses, analysis results, conclusions, and recommendations. High concentrations of ozone and other pollutants often existed in aloft layers covering much of the SoCAB. The layers were generally horizontal in structure. Model predictions of ozone did not agree with aloft ozone measurements. In the lower 200 meters above the ground (m agl) during the morning, ozone predictions were often significantly higher than measured concentrations. Model predictions of ozone above about 200 m agl were about 50 to over 100 ppb lower than measured concentrations.