Characterization of Ozone Episodes in the South Coast Air Basin: Effects of AirParcel Residence Time and Weekend/Weekday Differences

摘要

Ground level ozone, oxides of nitrogen, and meteorological data collected in theSouth Coast Air Basin from May 1 to October 31 for the years 1986-1993 were analyzed to discern the influence of the transport of air parcels of ozone and its precursor pollutants on concentrations in downwind areas, and to examine relationships between day-of-the-week and ozone levels. Ground-level air parcel transport across this region appears to be less of a determining factor for peak ozone values in downwind areas. Although, higher daily peak ozone concentrations were more common on weekend days when the precursor emissions were lower than weekdays, the worst ozone days showed the most pronounced percentage decrease in areas of maximum percentage decrease in early morning oxides of nitrogen concentrations.