The effects of urban heat islands (UHIs) comprise one of the most challenging issues in mitigating excessive heat. Existing studies have reported cooling effects from small greenspaces (SGs) and building-shaded spaces (BSs). However, more empirical studies are necessary to fully investigate the role of SGs in heat reduction as a cooling solution for urban microclimatic design and planning. In addition, only a few previous studies have used field studies to examine the cooling effects of SGs and compare them to those of BSs. The purpose of this study was to assess the cooling degrees of SGs and BSs and compare them at the urban block level. Six urban blocks located in Seoul, South Korea were selected as the study area. Based on block size, the selected urban blocks were divided into three pairs featuring different sizes of greenspace. Air temperature was measured via a transect survey on six clear, hot summer days. Datapoints were then classified into three landcover types: SGs, BSs, and paved spaces (PSs) exposed to solar radiation. To measure the cooling effects and compare the air temperatures of each cooling factor, a series of T-tests and ANOVA tests were conducted, after performing a spatial analysis of each block. The result show that the cooling effects of SGs surpassed those of BSs. The SGs’ cooling effects on blocks with larger greenspace were greater than those with small greenspace. In blocks with larger greenspace, SG’s cooling benefits outweighed those of BSs. It is also notable that block size was a decisive factor affecting the magnitude of cooling degrees; SG brought the greatest microclimatic benefits for the largest blocks. Our findings will contribute to optimal cooling designs using SGs and BSs by illustrating where SGs should be included to facilitate cost-effective cooling.

城市热岛 (UHI) 的影响是缓解过热的最具挑战性的问题之一。现有的研究报告了小型绿地 (SG) 和建筑物阴影空间 (BS) 的冷却效果。然而，需要更多的实证研究来充分研究 SG 在作为城市小气候设计和规划的冷却解决方案的热量减少中的作用。此外，只有少数先前的研究使用现场研究来检查 SG 的冷却效果并将其与 BS 的冷却效果进行比较。本研究的目的是评估 SGs 和 BSs 的降温程度，并在城市街区​​级别进行比较。位于韩国首尔的六个城市街区被选为研究区域。根据街区大小，选定的城市街区被分为三对不同大小的绿地。气温是通过在六个晴朗炎热的夏日进行的横断面调查来测量的。然后将数据点分为三种土地覆盖类型：SG、BS 和暴露于太阳辐射的铺砌空间 (PS)。为了测量冷却效果并比较每个冷却因子的空气温度，在对每个块进行空间分析之后，进行了一系列 T 检验和方差分析。结果表明，SGs 的冷却效果优于 BSs。SGs 对绿地面积较大的街区的冷却效果大于绿地面积较小的街区。在拥有更大绿地的街区中，SG 的冷却效益超过了 BS。同样值得注意的是，块大小是影响冷却程度大小的决定性因素；SG 为最大的区块带来了最大的小气候效益。