University of Tehran/Springer International Journal of Environmental Research 1735-6865 8 4 2014 10 01 Spatial Pattern of Ground-Level Ozone Concentration in Dallas-Fort Worth Metropolitan Area 897 902 782 10.22059/ijer.2014.782 EN P.F. Hudak Department of Geography, University of North Texas, 1155 Union Circle #305279, Denton, TX 76203-5017, USA Journal Article 2014 10 10 The objective of this study was to analyze spatial patterns of ground-level ozone concentration<br />in the Dallas-Fort Worth, Texas metropolitan area. Average daily maximum eight-hour ozone concentration,<br />number of days with concentrations exceeding 75 ppb, average outside air temperature, and resultant wind<br />direction at 20 monitoring stations were compiled for January-December, 2013. Recent estimates of population<br />and vehicle miles traveled were also compiled for 12 counties with ozone monitoring station(s). Ozone levels<br />and resultant wind directions were mapped for representative months in each season. On several days from<br />May-October, eight-hour ozone measurements exceeded 75 ppb. September, followed by August, produced<br />the highest ozone concentrations, as well as the most observations exceeding 75 ppb. Late spring and summer<br />months also showed the greatest range in ozone concentrations; during this time period, sustained southeasterly<br />winds caused distinct clusters of high ozone concentration at the northern perimeter of the study area.<br />However, ozone concentrations at individual monitoring stations were not associated with population or<br />vehicle miles traveled in counties occupied by those stations. https://ijer.ut.ac.ir/article_782_454163eedfee68e57e13154d8139cee0.pdf