Review of observation-based analysis of the regional factors influencing ozone concentrations

Some of the approaches that have been developed in the Aeronomy Laboratory and used to determine the rate and amount of ozone that is photochemically produced in the atmosphere from human-made and natural ozone precursors are reviewed below. The results were obtained from analysis of our field measurements that were made in the United States of the concentrations of O3, O3-precursors, the photochemical intermediates, and other photochemical products, as well as other atmospheric parameters. The utility of these approaches to identify the individual processes that lead to the formation and loss of ozone and O3-precursors are described and some of the crucial uncertainties that still remain are identified. The information obtained using these observational approaches include: (1) the apportionment of volatile organic compounds (VOCs), carbon monoxide (CO) and the oxides of nitrogen (NOx=NO+NO2) among the various anthropogenic sources; (2) the importance of natural VOCs/CO and NOx relative to anthropogenic VOCs/CO and NOx in photochemical ozone production; (3) identification of the mechanism for the photochemical chemical production and photochemical processing; (4) the determination of the instantaneous rate of photochemical production of O3; (5) the efficiency of tropospheric ozone production relative to the NOx concentrations; (6) the importance of NOx relative to VOCs and CO in determining observed O3 levels.