Assessing heat stress relief measures to enhance outdoor thermal comfort: A field study in China's cold region. (May 2022)

• Record Type: Journal Article
• Authors: Li, Yijun; Hong, Bo; Wang, Yanbo; Bai, Huifei; Chen, Huiying
• Is Part Of: Sustainable cities and society. Volume 80(2022)
• Publication Date: 2022-05
• Subjects: Outdoor thermal comfort (OTC) -- Mist spraying system -- Shade -- Physiological responses -- Predictive model -- China's cold region; Sustainable urban development -- Periodicals; Sustainable buildings -- Periodicals; Urban ecology (Sociology) -- Periodicals; 307.76
• DOI: 10.1016/j.scs.2022.103813
• Languages: English
• ISSNs: 2210-6707

Abstract

Highlights: Effects of heat stress relief measures on OTC in Xi'an, China were investigated. Mist spraying and shade devices significantly improved pedestrian OTC. UTCI reductions were 12.31 °C (shade+mist), 8.03 °C (mist spraying) and 3.48 °C (shade). Shade+mist device provided the greatest mean skin temperature reduction. Predictive models of MST relevant to Ta, RH and Tmrt were established. Abstract: We recruited 72 healthy college students on a university campus in Xi'an, China to investigate the effectiveness of heat stress relief measures (shade, mist spraying and shade+mist) on enhancing outdoor thermal comfort. Using the Universal Thermal Climate Index (UTCI) and mean skin temperature (MST), we evaluated respondents' thermal and physiological responses. We found that: 1) Mist spraying and shade were effective in improving respondents' outdoor thermal comfort. The cooling effect of mist spraying was more effective than shade, while shade+mist provided a wider thermal comfort range. 2) UTCI declined among cooling strategies by 12.31 °C (shade+mist), 8.03 °C (mist spraying) and 3.48 °C (shade) on average. 3) Shade and mist caused similar cooling effects on skin temperature (ST), but MST plateaued 5 min after exposure to these cooling environments in isolation. Shade+mist provided the greatest cooling effect with MST continuing to drop as the exposure continued. 4) Predictive models showed that MST in shade, mist spraying and shade+mist decreased 0.24, 0.21 and 0.16 °C, respectively when air temperature ( Ta ) declined 1 °C with constant relative humidity ( RH ) and mean radiation temperature ( Tmrt ). MST in shade, mist spraying and shade+mist decreased 0.05, 0.08 and 0.06 °C, respectively where RH increased 1% with constant Ta and Tmrt .