Air curtains are commonly employed in a variety of applications, including industrial ventilation systems, commercial buildings, fire safety measures, and smoke control systems. These devices are particularly effective in creating an invisible barrier of high-velocity air that separates indoor and outdoor environments. This barrier significantly reduces the infiltration of external air, thereby limiting the spread of pollutant gases within enclosed spaces. In addition to improving indoor air quality, air curtains contribute to temperature regulation and energy efficiency by minimizing air leakage and reducing heat transfer across the separation boundary. This study focuses on enhancing the performance of air curtains for pollutant containment, specifically the control of CO₂ gas mass fraction under varying air and pressure conditions that act as external disturbances. To achieve this, a sliding mode control (SMC) method is integrated into the regulation mechanism of the air curtain velocity. The SMC approach is known for its robustness and effectiveness in handling systems with high degrees of uncertainty or external perturbations. A wall jet configuration of the air curtain, combined with the SMC strategy, is subjected to comprehensive numerical simulations. These simulations evaluate the system’s ability to maintain effective pollutant separation and control in dynamically changing environments. The results demonstrate that the proposed control system significantly enhances the stability and performance of the air curtain, ensuring consistent pollutant containment. Even under critical pressure fluctuations, the system maintains optimal functionality, offering improved safety, and operational efficiency.