Introducing vegetation into towns and cities, for example through establishing green corridors which ensure a continuous character of urban green areas is a way to counteract negative effects of urban climate. The aim of the study was to assess the role of a green corridor and the contribution of vegetation to regulating the level of hourly tropospheric ozone concentrations in Legnica. Hourly values of tropospheric ozone concentrations (O3, μg m-3) and wind directions (D, °) collected between 2011 and 2014 from an urban background station for air quality monitoring of the Provincial Inspectorate for Environmental Protection were used in the study. To prepare a land cover map, data from the Database of Topographic Objects provided by the Geodesy and Cartography Department of the Marshal’s Office of the Lower Silesian Voivodship were used. The estimations of frequency of hourly O3 concentrations for given seasons of the year and the analysis of land cover within 2 km from the measuring point were made based on an 8-wind compass rose. In summer, the frequency of hourly O3 concentrations was assessed for every direction and for every hour of the day. A Pearson correlation matrix was generated to illustrate the relationship between land cover type and the frequency of pollution coming from each direction, Between 21:00 and 6:00, increased frequency of hourly O3 concentrations in the 0–40 μg m-3 range coming from the southwest was recorded, which accounted for 70–90% of all concentration ranges. Correlation analyses showed a statistically significant relationship between increased high vegetation coverage and decreased frequency of hourly O3 concentrations in the 41–80 μg m-3 range. It was demonstrated that between 2011 and 2014, during summers, hourly O3 concentrations <40 μg m-3 came most frequently from the direction characterised by the highest total share of vegetation-covered land. On the other hand, pollutants with concentrations in the 41–80 μg m-3 range came more frequently at night time from the directions characterised by compact and dense development. The obtained results demonstrated that in summer, the urban park, the Kaczawa River and the green areas along the river play an important role as a green ventilation corridor.
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This paper describes model tests conducted at the Wind Engineering Laboratory of Cracow University of Technology as the first stage of studies on dynamic action on the atmospheric boundary layer in order to reduce the effects of air pollution and smog. It focuses on the cooperation between a series of ventilation towers placed one by one (or row by row) in order to generate a continuous airstream with sufficient velocity to aid the natural ventilation of urban areas. The tests were conducted for three different terrain categories with varying roughness. Also tested were different wind speeds, different spacing between the towers and different configurations of the towers in each row. As a preliminary set of tests, this enabled verification of the feasibility of the solution and its effectiveness on a rough terrain that simulates urban areas.
PL
Niniejszy artykuł opisuje badania modelowe przeprowadzone w Laboratorium Inżynierii Wiatrowej Politechniki Krakowskiej w ramach pierwszego etapu studium dynamicznego oddziaływania na warstwę przyziemną atmosfery w celu redukcji zanieczyszczenia powietrza i smogu. Praca skupia się na współpracy kilku wież wentylacyjnych ustawionych jedna za drugą (lub rząd za rzędem) w celu utworzenia ciągłej strugi powietrza o dostatecznej prędkości, by wspomóc naturalną wentylację obszarów zurbanizowanych. Badania przeprowadzono dla trzech różnych kategorii chropowatości terenu. Ponadto sprawdzono wpływ różnych prędkości strugi, różnych odległości pomiędzy wieżami i różnych wzajemnych konfiguracji wież w każdym rzędzie. Przeprowadzone badania wstępne pozwoliły na weryfikację wykonalności tego rozwiązania oraz jego wydajności na chropowatym terenie odpowiadającym obszarom zurbanizowanym.
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