Artificial turf is a synthetic surface designed to mimic the appearance and function of natural grass for applications like sports fields, playgrounds, and landscaping. While it offers durability and low maintenance, it becomes significantly hotter than living grass when exposed to direct sunlight. This phenomenon is rooted in the material science and physics of synthetic components interacting with solar radiation.
How Artificial Turf Absorbs and Retains Heat
Artificial turf gets hot primarily due to its synthetic material composition. The turf fibers are typically made from plastics like polyethylene, polypropylene, or nylon. These dark, dense, petroleum-based polymers have low reflectivity, readily absorbing incident solar radiation and converting most of the light energy directly into thermal energy, which is then stored within the material.
Natural grass possesses a powerful, built-in cooling system through evapotranspiration. This process involves the plant releasing water vapor, which carries heat away from the surface as it evaporates. Artificial turf lacks this natural cooling mechanism, allowing heat to accumulate without dissipation.
The infill material, often black crumb rubber made from recycled tires, significantly contributes to heat retention. This dark, granular material is spread between the synthetic blades for ballast and cushioning. Its color and density cause it to act as a heat reservoir, absorbing and holding heat long after peak sun exposure and maintaining elevated surface temperatures into the evening.
The Health Risks of High Surface Temperatures
The intense heat buildup on artificial turf poses health and safety risks, particularly for athletes and children. Studies show that synthetic turf surface temperatures can be 9.4°C to 33.7°C (17°F to 60°F) higher than adjacent natural grass. On hot days, turf surfaces often reach temperatures between 120°F and 180°F.
This extreme surface temperature presents a direct risk of contact burns. Skin contact with surfaces exceeding 51°C (124°F) can lead to second-degree burns within 90 minutes. If the temperature climbs to 70°C (158°F), irreversible skin burns can occur in less than one second. This is a concern when players fall or slide, or for children playing barefoot.
The high surface heat also radiates upward, creating a hot microclimate just above the field that affects core body temperature regulation. This radiant heat inhibits the body’s ability to cool itself through sweating and convection. This increases the risk of heat exhaustion, dehydration, and heat stroke, creating unsafe conditions for strenuous activity even when the air temperature is moderate.
Strategies for Reducing Turf Surface Heat
Facility managers and homeowners can adopt several strategies to mitigate the heat problem. The most immediate, temporary solution is to water the surface briefly with a hose or sprinkler system. This technique mimics the evaporative cooling process of natural grass and provides instant, short-term temperature reduction.
A more permanent solution involves the choice of infill material. Designers can opt for specialized, lighter-colored infills, such as silica sand or thermoplastic elastomer (TPE) granules, which absorb less solar energy than traditional black crumb rubber. Some modern infills are coated with phase-change materials or utilize advanced cooling technologies designed to reflect light and retain moisture.
Facility scheduling can be adjusted to avoid the most intense solar radiation. Activities should be scheduled for early morning or late evening to bypass peak afternoon sun exposure when surface temperatures are highest. Installing shade structures, such as shade sails or awnings, over parts of the field can block direct sunlight and reduce surface temperatures.