On photochemical air pollution potential in southern California derived from ozone data from 16 monitoring stations

Abstract

Average hourly ozone volume fractions from ten automatic monitoring stations in the Los Angeles and six in the Riverside area for the April through September season in the years 2000 to 2005 have been analysed on the basis of recently introduced photochemical pollution (PP) indicators. Although considerably high indicator values were found for almost all the stations, surprisingly, some (e.g. Palm Springs) exhibit low daily maximum-to-minimum ratios of hourly ozone values which is crucial for assessment of a low PP by the given indicator method, despite the overall high ozone concentrations recorded. At such stations, in contrast to elsewhere, a characteristic quasi normal distribution of all ozone hourly volume fractions exists which could be a consequence of poor vegetation or some special meteorological conditions there. Compared with a similar assessment in central Europe and the Mediterranean region, the present analysis shows that PP problems in California are significant.