Warm Air Leads to Hazardous Ground Temperatures When Walking Dogs in Built and Natural Environments

Two case studies in Texas, one in a built environment and another in a natural setting, illustrate potential ground heat hazards when walking dogs on warm days. In the first case, temperatures of four different ground surfaces—concrete, grass, chip seal, and tar—were measured along a street in a suburban neighborhood. The study involved two morning and two afternoon surveys of 30 sampling locations where all four materials were present. Air temperatures, typical of the study area in summer, ranged from 78.0 oF (25.6 oC) in the morning to 96.1 oF (35.6 oC) in the afternoon. Ground surfaces reached much higher temperatures, exceeding 150 oF (65.6 oC), in the afternoon surveys. Median temperatures were highest in tar, followed by chip seal, concrete, and grass. The second case involved shallow lake water and various types of mud, sand, cobbles, rock fragments, and grass along a nature trail. Air temperatures ranged from 74.7 oF (23.7 oC) at 8:00 a.m. to 92.5 oF (33.6 oC) at 6:00 p.m. Ground temperatures varied considerably with material and time of day, ranging from 76.4 oF (24.7 oC) at gray cobbles and beige rock at 8:00 a.m. to 125.7 oF (52.1 oC) at brown sand at 4:00 p.m. Over the day, temperatures were highest at brown sand and lowest in water and moist sand.