Equations of a new puff model for idealized urban canopy

Abstract During a leakage of hazardous materials, emergency services need to predict the evolution of the accident. In such situations, fast models are used. Such models can produce reasonable results for long-term leakages, but short-term leakage results can be underestimated by as much as a full order of magnitude (shown in the COST ES1006 project). Hence, the main aim of this paper is to present equations for recalculating the continuous source results to achieve results valid for the short-term source. The model would consist of a sub-model utilized for the continuous source in combination with the equations introduced in the paper. The outputs obtained are the probability density functions of the puff characteristics: dosage, maximum concentration, and 99th and 95th percentiles of concentrations. These functions can help to estimate the situation not only for the mean case, but also for the extreme cases.