Modeling air flow and dispersion of harmful substances in conditions of complex geometry

The paper presents a mathematical model for simulating air flow and pollutant dispersion in complex urban geometry. The behavior of air flows and pollutant concentrations in street canyons is studied, taking into account the influence of architectural features of urban development. The effect of such factors as the ratio of the height and width of buildings on turbulence and particle deposition is analyzed. The application of the Navier-Stokes equations for calculating the fields of air velocity and pressure in a confined space is studied. The influence of real meteorological conditions, including wind data obtained from OpenWeatherMap, on the initial and boundary conditions of the model is determined. It is found that complex geometry, including narrow streets and tall buildings, significantly affects the efficiency of pollutant dispersion. A numerical solution to the problem is formed using the finite difference or finite element method, which ensures stability under irregular discretization. A computer simulation is developed that allows predicting the spread of pollutants in real urban conditions. The use of the obtained model for assessing environmental safety and planning urban infrastructure is substantiated. A detailed description of the methodology is provided, including mathematical equations and calculation algorithms.