Short‐term temporal variability of volatile contaminant concentrations in soil gas related to soil–atmosphere interface dynamics: Two case studies in the Veneto region (Italy).

This article focuses on the variability of volatile organic compound (VOC) concentrations in soil gas at two contaminated sites in the Veneto region of Italy and its implications for monitoring and risk assessment. Continuous monitoring revealed a pronounced 24-hour cyclic variation in soil gas VOC concentrations correlated with differential pressure between soil and atmosphere and buoyancy vertical flux, driven by daily soil heating and cooling cycles. These findings challenge conventional soil gas sampling methods, which typically rely on infrequent, time-averaged measurements and diffusion-based models assuming continuous emission, potentially misrepresenting actual exposure risks. The study highlights the need to integrate continuous monitoring and differential pressure measurements to better capture temporal variability and improve the interpretation of soil gas data for environmental risk assessments.