Study On The Influence Of Street Valley Morphology On The Diffusion Of Indoor And Outdoor Traffic Pollutants In Adjacent Space Buildings

Due to the rapid urbanisation process in China,the scale of urban construction is expanding and the density of buildings and the number of urban population is increasing rapidly.While urban prosperity presents itself,there are more and more problems that adversely affect the health of residents due to changes in the urban environment,such as environmental pollution caused by car traffic and the heat island effect in urban centres.People who work and live in cities spend most of their time indoors,and the outdoor air environment of buildings under natural ventilation conditions directly affects the quality of the indoor environment.Therefore,the respiratory health of people working and living in cities is closely linked to the indoor and outdoor air quality of urban buildings.Currently,urban vehicular traffic pollution is one of the main causes of air environment degradation,and urban valleys and adjacent space areas are places where residents and different groups of people are relatively concentrated,with a long residence time and a high risk of pollutant exposure,while the ability of traffic pollutants to disperse in urban neighbourhoods is closely related to the morphological layout of the city,the role of the wind environment and the shape and structure of urban buildings.At present,there are few studies on the control of pollutants in adjacent spaces,and it is of practical significance to carry out research on urban environmental management to understand the diffusion mechanism of pollutants in adjacent spaces,in order to effectively control and improve the surrounding and indoor air environment of adjacent buildings,as well as to implement the current policy of a healthy China.This paper adopts numerical simulation methods: firstly,the feasibility of the numerical calculation model is verified;secondly,the correlation between the spatial patterns under different working conditions and the concentration of pollutants in the outdoor and indoor areas of adjacent spaces is investigated from three aspects: the geometry of the street valley,the morphology of the building monoliths on both sides of the street valley,and the morphology of the external skin of the building elements in the adjacent spaces of the street valley,so as to understand the diffusion mechanism of pollutants in the adjacent spaces.The study then quantified the dose levels of human intake in the adjacent outdoor space and indoor building respectively to obtain the range of morphological parameters for pollutant control,based on which the exposure risk of residents was evaluated and the types of street valley morphology with higher exposure risk were deduced,forming the research results of effective pollution control through street valley morphology.The study found that the indoor and outdoor dispersion levels of pollutants in adjacent buildings in the street valley were significantly correlated with the changes in street valley morphology and single buildings on both sides of the street valley,and to a lesser extent with the building outcrops.For example,if the width of the balcony is between 1.2m and 1.8m,the exposure of people indoors will be relatively reduced,but the exposure of people moving outdoors will be increased at the same time.The difference in exposure and health risk between indoor and outdoor occupants of a building is large,on average about 9-11 times greater than that of outdoor occupants.The findings of this study have been validated in practical cases and are intended to provide theoretical support and a practical basis for urban design,urban planning and architectural design processes that aim to control pollutants.