Seasonal Risk Assessment of Liquefied Petroleum Gas Leakage in Urban Area: A case Study of Meghna Filling Station, Dhaka

Liquefied Petroleum Gas (LPG) leakage presents a critical safety concern, especially in densely populated urban areas. This study evaluates the seasonal risk dynamics of an LPG release scenario at Meghna Filling station in Dhaka, Bangladesh, Using the ALOHA 5.4.7 air dispersion model to simulate hazard zones under differing atmospheric conditions. Simulations were conducted for both summer and winter conditions to assess toxic gas dispersion, explosion overpressure and thermal radiation hazards based on Acute Exposure Guideline Levels (AGELs) and Lower Explosive Limit (LEL) thresholds. Result show that winter conditions lead to wider dispersion zones across all risk indicators due to increased atmospheric stability and reduced vertical mixing. AGEL-3 concentrations (life- threatening exposure) extended approximately 300 meters in winter compared to approximately 240 meters in summer. Similarly, explosion over pressure zones above 3.5 psi stretched 370 meters in winter, compared to 290 meters in summer. However, in fixed locations near the source, the heat from the gas lasted longer in summer. The thermal radiation intensity that causes second-degree burns (6 kW/m²) stayed about 1 minute in summer, but only 0.4 minutes in winter. These seasonal differences significantly influenced the spatial extent and intensity of hazard zones. The findings emphasize the necessity for season-specific emergency planning and safety measures in LPG storages and distribution facilities to better protect public health and infrastructure. Dhaka Univ. J. Sci. 73(2): 177-186, 2025 (July)