The effect of shale gas activities on ground-level ozone pollution in the Dallas-Fort Worth area is studied in detail here. Ozone is a highly reactive species with harmful effects on human and environment. Shale gas development, or fracking, involves activities such as hydraulic fracturing, drilling, fluid mixing, and trucks idling that are sources of nitrogen oxides (NOX) and volatile organic compounds (VOC), two of the most important precursors of ozone. In this study two independent approaches have been applied in evaluating the influences on ozone concentrations. In the first approach, the influence of meteorology were removed from ozone time series through the application of Kolmogorov-Zurbenko low-pass filter, logarithmic transformation, and subsequent multi-linear regression. Ozone measurement data were acquired from Texas Commission on Environmental Quality (TCEQ) monitoring stations for 14 years. The comparison between ozone trends in non-shale gas region and shale gas region shows increasing ozone trends at the monitoring stations in close proximity to the Barnett Shale activities. In the second approach, the CAMx photochemical model was used to assess the sensitivity of ozone to the NOX and VOC sources associated with shale oil and gas activities. Brute force method was applied on Barnett Shale and Haynesville Shale emission sources to generate four hypothetical scenarios. Ozone sensitivity analysis was performed for a future year of 2018 and it was based on the photochemical simulation that TCEQ had developed for demonstrating ozone attainment under the State Implementation Plan (SIP). Results showed various level of ozone impact at different locations within the DFW region attributed to area and point sources of emissions in the shale region. Maximum ozone impact due to shale gas activities is expected to be in the order of several parts per billion, while lower impacts on design values were predicted. The results from the photochemical modeling can be used for health impact assessment and air quality management purposes. Both studies in this research show that the impact of shale gas development on local and regional level of ozone is significant, and therefore, it should be considered in the implementation of effective air quality strategies.