**4. Discussion**

**Figure 12.** Air temperature distribution in the middle of a summer day (22nd July, 2016) at 1.5 m height.

74 Sustainable Cities - Authenticity, Ambition and Dream

**Figure 13.** Sky view factors in the middle of a summer day (22nd July, 2016) at 1.5 m height.

**Figure 14.** Mean radiant temperature in the middle of a summer day (22nd July, 2016) at 1.5 m height.

Urban ventilation plays an important role in the urban environment. In summer, urban ventilation contributes to urban heat dissipation and urban heat island mitigation. In winter, high wind speed accelerates the aggregation of air pollution. Results demonstrated that the urban typology affects urban ventilation and urban air quality. However, it is usually difficult to change the urban form over a short period in areas that have already been developed.

Most of China's cities have undergone fast economic growth, urban expansion, and urban redevelopment. This unique situation is the reason of the rapid environmental degradation in Chinese cities, which could also be useful to the other countries. The fast change in form in China's urban areas has provided an opportunity to optimize urban environments in short periods. This requires an urgent establishment of related policies to regularize environmental urban development and redevelopment.
