Developing a thermal suitability index to assess artificial turf applications for various site-weather and user-activity scenarios

Abstract

Lawns are highly recognized and indispensable elements in the urban landscape. Due to water-saving, low maintenance cost, and avoided health-environmental impacts of agrochemical usage, artificial turf (AT) has increasingly replaced some natural turf (NT) sports fields and recreational lawns. It remains controversial whether AT is a healthy alternative to NT. We asked the research question, “Where and for whom the AT is (or isn't) suitable regarding user thermal sensation partaking various activities?” We established a field experiment at adjoining AT and NT fields in humid-tropical Hong Kong. Detailed microclimatic data were recorded under sunny, cloudy and overcast weather conditions to calculate the modified physiological equivalent temperature (mPET) as a thermal comfort index. Activities covering a range of metabolic rates were selected to evaluate user thermal sensation. AT experienced considerably raised ground surface temperatures on sunny days with a consequential increase in near-ground ambient air temperatures and the environs. The inter-turf temperature difference was somewhat subdued under cloudy and overcast weather. A regression model allowed the successful development of a nine-point thermal suitability index (TSI) to assess AT applications and provide a simple rule-of-thumb for design practice. To avoid undue heat stress, AT use can only be recommended for certain site-weather and user-activity scenarios. The TSI can be applied to other climatic zones by gleaning on-site microclimatic data and enlisting the proposed regression-modelling method. A comprehensive AT assessment scheme can be developed by incorporating the TSI to inform future AT installation and use decisions.