Modeling the Impact of Urban Three-Dimensional Expansion on Atmospheric Environmental Conditions in an Old Industrial District: A Case Study in Shenyang, China

Abstract

The rapid expansion of cities has caused enormous changes in the underlying surface, and coupled with the intensification of human activities, it has resulted in a series of ecological and environmental problems, such as urban heat island, air pollution, and so on. Through combining building height and air pollution source information, and using the computational fluid dynamics (CFD) model, this study simulated the distribution characteristics of wind speed, temperature and SO 2 concentration under the condition of urban three-dimensional expansion, and then the analysis was performed on the influence of three-dimensional expansion on air environment diffusion during winter and spring in the Shenyang Tiexi District under the urban landscape pattern of 2005 and 2011. Monitoring data from 10 sampling sites were used to validate the model. The results showed that the R 2 values for wind speed, temperature and SO 2 were 0.76, 0.79 and 0.64, respectively. The wind speed, temperature and SO 2 concentration distribution pattern at the same height of the study area is obviously different because of the differences in urban building height, density and layout between 2005 and 2011. From 2005 to 2011, with the change in the urban architecture landscape pattern, the city corridor significantly changed.

Does the Spatial Pattern of Plants and Green Space Affect Air Pollutant Concentrations? Evidence from 37 Garden Cities in China

“…The production of SO 2 in urban air pollution mainly originates from coal combustion and industrial emissions, and studies have demonstrated that SO 2 concentrations were lower in areas with rich vegetation under different spaces in cities [ 32 ]; hence, the increase in the area share of forestland patches effectively enhanced the efficiency of SO 2 absorption by urban plants and reduced the SO 2 air content in cities. Simultaneously, as a gas, SO 2 was more susceptible to wind speed, temperature, and humidity; hence, the single vertical structure of grass greenery was more conducive to the circulation of urban winds and the transportation of SO 2 pollutants from the inner city to the outer city, to achieve a lower average SO 2 concentration [ 33 ]. The diffusion of SO 2 is mainly influenced by wind speed and direction, and in areas with high building density due to the blockage of tall buildings resulting in low internal wind speed, SO 2 concentration was not easily diffused.…”

Impacts of urban densification and vertical growth on urban heat environment: A case study in the 4th Ring Road Area, Zhengzhou, China

“…(Bennet and Ewenz, 2013) showed that when H/W = 1, the temperature rise at street level stopped and even reversed at a higher BH. (Li et al, 2020a) studied the temperature at different heights and found that the extent of the high temperature region increased and then decreased at 30m as height increased. The majority of streets in this study are 20-24m wide, so for BH≥24, H/W≥1, and therefore our city-wide analysis in Zhengzhou would appear to be consistent with these localised studies from other cities.…”

Air Pollution Dispersion Modelling in Urban Environment Using CFD: A Systematic Review

“…As vehicles play a significant role in urban pollution, the bulk of the reviewed cases employed a ground-level source of emission to mirror traffic pollution, as evidenced by Figure 13. Meanwhile, some articles (e.g., [58,59,68,71,73,75,[94][95][96]) investigated the dispersion of pollutant from stack sources located on top of buildings, which is an equally important factor as it can negatively influence the air quality in the surrounding areas. In contrast, the pollutant in 3 studies [87,88,90] was injected into the computational domain from the inlet plane.…”