Author/Authors :
Fred M. Vukovich، نويسنده , , John Sherwell، نويسنده ,
Abstract :
Fifteen years of ozone data from the United States Environmental Protection Agencyʹs (EPA) Aerometric Information Retrieval System (AIRS) and surface and upper air meteorological data from National Weather Service (NWS) stations were used to determine the meteorological conditions in the Baltimore–Washington corridor area that are important in characterizing ozone variations. Three data sets were used in this study: the initial 15-year data set; a subset of the complete 15-year data set that was a 15-year summer data set; and another subset of the complete 15-year data set that only included those days when the daily maximum ozone concentration (DMOC) was greater than or equal to 100 ppb (DMOC 100 ppb). The results from this study indicated that the meteorological terms that affect ozone in the Baltimore–Washington corridor were compartmentalized; that is, the results were dependent on which data set was used in the study. When the entire 15-year data set was considered, the meteorological parameters that influenced ozone variations were temperature and dewpoint. The principal meteorological term, when only the 15-year short-term variations (i.e., variations with periods less than 30 days) of ozone were considered, was sky cover. When the 15-year summer data set was considered, the principal meteorological terms involved in the variation of ozone were temperature and sky cover; and when the data set in which the limitation DMOC 100 ppb was used, the principal meteorological terms were surface wind speed and sky cover. The results from this study indicated that high temperatures and large concentrations of water vapor are a necessary, but not a sufficient, condition for high ozone to be found in the Baltimore–Washington corridor. The sufficiency condition is satisfied when significant amounts of solar radiation reach and when stagnation conditions prevail in the surface layer at the same time.
