Urban ventilation planning and its associated benefits based on numerical experiments: A case study in beijing, China

Abstract

Urban ventilation planning (UVP) are critically important to sustainable and green urban development. However, the climatic-environmental effects and benefits of urban ventilation corridors have yet to be fully understood. In this study, high-resolution simulation tests were carried out for winter of 2018 and summer of 2019 using the weather research and forecasting model (WRF) coupled with the urban canopy model (UCM) and the refined surface type and UVP of Beijing City. After the construction of the ventilation corridors, the average temperature in the Beijing urban area can be reduced by 0.18 °C, and the wind speed and relative humidity can be increased by 0.33 m s−1 and 2.83%, respectively. The major contributions of the ventilation corridors to local meteorological elements are the wind speed enhancement-induced advection effect and the improvement of the turbulent flux over urban surface. Further, the cost-benefit analysis of UVP show that the urban heat island intensity (UHII), the average PM2.5 concentration, and the number of days with light or above levels of air pollution will be decreased by 13.7%, 11.7%, and 20.2%, respectively. This implies that, disregarding the reduction of the UHII and its effect, urban ventilation corridor is conducive to improving the winter urban living environment. However, the problems of haze pollution cannot be completely resolved by ventilation corridors alone, and the weakening of the winter UHII in the northern city is a disadvantage to energy-saving and habitat comfort. Our findings provide a reference base for policy decisions and technical guidelines for UVP of high-density cities.