<p>Atmospheric water harvesting (AWH) offers a promising solution to global water scarcity, yet questions remain regarding the impact of air pollution on water quality, particularly the potential transfer of combustion-derived organic contaminants. In this study, we evaluate the resilience of a custom-built AWH system that uses potassium acetate as a liquid desiccant and vacuum-assisted evaporation for water regeneration. Controlled contamination tests were performed by introducing emissions from a diesel engine and a two-stroke gasoline engine into the AWH system intake airflow. Gas chromatography–mass spectrometry (GC–MS) was employed to analyze both the intake air and the harvested water. The air samples revealed a complex mixture of volatile and semi-volatile organic compounds, including hydrocarbons (C₅−C₁₅), benzene, toluene, MTBE/ETBE, and polycyclic aromatic hydrocarbons, with total concentrations up to 5.3 mg/m³. In contrast, none were detected in the water, with all results falling below the detection limit of 50 μg/L. These findings demonstrate that the desiccant–vacuum AWH system provides effective phase-change separation and intrinsic barrier properties against organic air pollutants. This is, to our knowledge, the first study to perform a direct GC–MS comparison of air and water in an AWH context under controlled pollution exposure, providing strong evidence that such systems can produce clean water even in heavily contaminated environments.</p>