NOx or VOC limitation in East German ozone plumes?

The ozone forming potential of VOCs and NOx for plumes observed from several cities and a power plant in eastern Germany was investigated. A closed box model with a gas phase photochemical reaction mechanism was employed to simulate several scenarios based upon aircraft observations. In several of the scenarios, the initial concentrations of NOx, VOCs, and SO2, were reduced to study the factors limiting the O-3 production. Ozone production was limited by the initial VOC concentrations for all of the simulated plumes. Higher O-3 concentrations were produced with reduced initial NOx. In one sample with high SO2 mixing ratios (>100 ppb), SO2 was also identified as a significant contributor to the production of O-3.