Quah Yan Hsien

Resilience of public housing against urban heat intensities: Case study in Singapore

Built-up urban areas experience higher temperature than their rural counterparts, known as the Urban Heat Island (UHI) phenomenon. The UHI is intensifying due to the simultaneous pressures of global warming and rising urban population density. As UHI-induced heat stresses severely affect human health, there is an urgent need for urban housing that mitigates the intensifying UHI effects. Of particular importance is the design of public housing in urban centres, to ensure that even the most vulnerable living in public housing are sufficiently safeguarded against rising UHI intensity and their associated health risks. Yet, there exists a literature gap precisely at the intersection of urban public housing design and UHI intensity, particularly in high-density tropical cities which are most at risk. In response, this study investigates design parameters of urban public housing and their corresponding effects on UHI intensity, with a case study in Singapore. Singapore was selected for its duality as a dense urban centre in the tropics, coupled with the statistic that 80% of households reside in public housing. Public housing parameters for all 12,674 public housing blocks in Singapore were investigated for their effects on UHI intensity. First, Sky View Factor methodology was applied to derive the UHI intensity map of Singapore measured in air temperature, as air temperature is a more accurate proxy for human health than land surface temperature. Next, eight public housing parameters were identified and their bivariate correlations with UHI intensity were investigated. Linear regressions were conducted on sub-quartiles of the significant parameters to determine their specific proportion that contributes to lowest UHI intensity. To mitigate UHI intensity, the findings recommend that public housing blocks should be i) mid-rise in height within the range of 13–38 floors, ii) positioned in as close proximity as feasible to water bodies and no further than 1122m, iii) positioned in as close proximity as feasible to green spaces and no further than 436m, and iv) positioned at least 70m apart from adjacent blocks. Importantly, these recommendations are not limited to Singapore’s public housing context, but are transferable, applicable, and adaptable to inform public housing decisions in other high-density urban cities who are similarly at heightened risks of intensifying UHI effects. The findings can guide urban planners, policymakers, and public housing stakeholders in designing public housing that protects even the most vulnerable from rising UHI intensities in Singapore and similar high-risk countries.