Grazed pastures can be introduced as a dominant source of nitrous oxide (N2O), a high potent greenhouse gas. Although past studies have examined N2O emissions in relation to soil physical properties, linking emissions with soil gas diffusivity (Dp/Do) and its dependency on soil physical properties and soil moisture are lacking. This study empirically correlated the N2O emission dynamics in differently-sized aggregated soils using coarse (2–4 mm) and fine (< 0.2 mm) aggregates, and seven different combinations with varying fine aggregate fractions (F = 0, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 1.0). Repacked samples of different combinations were saturated with KNO3 (1800 μg mL−1) solution and were systematically drained to nine different matric potentials (−1 kPa to −10 kPa), followed by an air-dry step (−30 kPa). At potential levels, N2O flux and Dp/Do were measured. The highest and lowest peak of N2O were observed as F = 1.0 at Dp/Do = 0.002 and F = 0.7 with the lowest Dp/Do respectively.