Légszennyező anyagok terjedése városokban - A magas épületek hatása a légszennyezettségre

One of the most significant objectives of air pollution control is the reduction of concentration of traffic related pollutants in cities. These pollutants travel with air, so their dispersion depends basically on the characteristics of atmospheric flow field under urban canopy, influenced by buildings and vegetation. This study gives a short overview on building related flow structures influencing mainly the transport of pollutants then it describes the various mechanisms of the dispersion of pollutants in urban environment. One of the mechanisms significant from the point of view of air pollution control is the downflow close to the upstream front elevation of high buildings transporting clean air to pedestrian level. More significant is the effect of separation bubble developing over the downstream front elevation, lifting up the polluted air from the pedestrian level and transporting it in higher layers of atmosphere. The methods of investigation used in fluid mechanics: wind tunnel experiments and numerical simulation of flows are suitable not only for determination of wind forces but also for prediction of effect of buildings on air pollution and pedestrian wind comfort