Polyvinyl fluoride (PVF) film bags are widely used for the temporary storage of air samples prior to analysis due to their durability, toughness, and chemical inertness to a broad range of compounds. However, factors such as temperature and storage time can significantly affect the performance of PVF film bags, with important implications for the accuracy of sample analysis. This study evaluated the stability of syngas in Tedlar® PVF film bags under varying storage temperatures (−20 °C, 25 °C, and 38 °C) and durations (0–168 h), with Pearson correlation analysis conducted to assess the impact of these conditions. The results revealed that both storage temperature and time notably influence syngas stability, particularly for hydrogen and carbon dioxide. A strong negative correlation was observed between the concentrations of these gases and temperature, with the most pronounced negative correlations at 38 °C, showing coefficients of −0.974 and −0.977 for hydrogen and carbon dioxide, respectively. At 25 °C and 38 °C, hydrogen and carbon dioxide exhibited significant concentration losses, with recovery rates of 81.2 ± 4.5% and 66.9 ± 1.2% for hydrogen, and 90.9 ± 1.1% and 89.3 ± 1.5% for carbon dioxide, respectively. In contrast, gases stored at −20 °C for seven days maintained recovery rates exceeding 95%. This study identifies low-temperature storage in PVF film sampling bags as an effective method for preserving syngas integrity ensuring data accuracy for informed syngas utilization and application decisions.