Modelling the atmospheric dispersion of ammonia in an industrial area in northern Greece

Air pollution is one of the greatest challenges for ecosystems globally, as it adversely affects not only human health, but also water resources, land, animals and plants. The composition of atmospheric air is changing due to urbanization, industry, land surface alteration, climate change and global population increase. Studying the dispersion of atmospheric pollutants is a crucial issue for better urban, regional and global predictions of air quality. Dispersion models have proven a valuable tool in estimating the concentration of air pollutants produced by industrial facilities, as well as predicting future concentrations under specific scenarios (e.g., changes in emission sources or emission rates). The objective of this research was to examine a number of hypothetical industrial accident scenarios, including the local spread of ammonia from an industrial zone located 5 km east of the coastal city of Kavala in northern Greece. For that, the Atmospheric Dispersion Modeling System 5 (ADMS-5) was used as a safety and emergency planning tool, in order to model instantaneous releases (puffs) of ammonia and to investigate changes in ground-level concentration. To determine the structure of the atmospheric boundary layer, seven different meteorological conditions which correspond to the Pasquill-Gifford stability categories A-G were considered. The maximum ground-level concentration (1400 - 2400 μg/m3) occurred in slightly stable and moderately stable conditions (categories E and F) very close to the source, while in extremely stable conditions (category G) the puff remained stagnant for over 600 s after release. The lowest ground-level concentration (300 μg/m3) occurred with slightly unstable conditions (category C). The obtained results can be used for safety and emergency planning reasons and highlight the importance of atmospheric stability on the fate of accidental industrial releases.