The influence of spatial form of different functional blocks on pollution reduction and carbon reduction: Evidence from Hefei City

Air pollution (PE) and carbon emissions (CE) are obstacles to achieving the Sustainable Development Goals (SDGs) globally. The development intensity and spatial form of urban blocks could affect PE-CE. The relationship between these factors and PE-CE was investigated in this study. The results showed that: (1) The spatial distribution of PE-CE and various factors showed that the spatial distribution of PE was consistent with normalized difference vegetation index (NDVI), average height (AH) and building density (BD), while the spatial distribution of CE was consistent with BD, floor area ratio (FAR) and building otherness (BO). Neighbourhoods with high NDVI have low CE. (2) Correlation analysis shows that in general, FAR, BO and PE-CE were positively correlated, while NDVI was negatively correlated. The correlation of other factors in different functional blocks has its own characteristics. (3) For the interpretation of random forest model, FAR has a strong interpretation in all functional areas. For CE, 50% were in public blocks, 19% were in residential blocks and 28% were in industrial blocks. For PE, FAR in residential blocks was 29%. (4) FAR, NDVI and AH were the most frequently judged as important factors. For residential blocks, the key factors affecting PE-CE are FAR, NDVI and AH. Public blocks are FAR, AH and block area (AREA). Industrial blocks are FAR, AREA, BD and BO.