The results of Module 4 focus on air quality impacts resulting from oil and natural gas (O&nG) exploration activities, particularly in the Front Range of Colorado. This comprehensive assessment encompasses the broader spectrum of activities within O&nG development, moving beyond fracking alone. By considering emissions throughout the entire lifecycle of well activities, this module provides a holistic view of O&nG’s influence on air quality. The study area’s significance lies in its inclusion of Denver and the Denver-Julesburg Oil and Gas Basin, a prominent O&nG development site. The region’s history of ozone non-attainment underscores the urgency of understanding O&nG emissions’ role in air quality. The rich dataset from the Front Range Air Pollution and Photochemical Experiment (FRAPPÉ) serves as a foundation for model simulations that compare scenarios with and without O&nG emissions. This approach contributes valuable insights into the impacts of O&nG activities on air quality, supporting evidence-based decisions to safeguard public health.