spatial pattern of ground-level ozone concentration in dallas-fort worth metropolitan area

the objective of this study was to analyze spatial patterns of ground-level ozone concentrationin the dallas-fort worth, texas metropolitan area. average daily maximum eight-hour ozone concentration,number of days with concentrations exceeding 75 ppb, average outside air temperature, and resultant winddirection at 20 monitoring stations were compiled for january-december, 2013. recent estimates of populationand vehicle miles traveled were also compiled for 12 counties with ozone monitoring station(s). ozone levelsand resultant wind directions were mapped for representative months in each season. on several days frommay-october, eight-hour ozone measurements exceeded 75 ppb. september, followed by august, producedthe highest ozone concentrations, as well as the most observations exceeding 75 ppb. late spring and summermonths also showed the greatest range in ozone concentrations; during this time period, sustained southeasterlywinds caused distinct clusters of high ozone concentration at the northern perimeter of the study area.however, ozone concentrations at individual monitoring stations were not associated with population orvehicle miles traveled in counties occupied by those stations.