The University of Massachusetts Amherst researchers state that this innovative fabric can cool the air beneath it by up to 8 degrees Fahrenheit.
The research team developed a sustainable mineral-polymer coating that is a combination of calcium carbonate and barium sulfate, which are natural minerals commonly found in chalk. The calcium carbonate particles effectively reflect visible and near-infrared light, while barium sulfate particles are adept at reflecting ultraviolet light. What makes their technique unique is that it can be applied on nearly any commercially available fabric
This cooling fabric may help anyone who participates in outdoor activities during summer heat, such as athletes, landscapers, youngsters, and beachgoers.
https://interestingengineering.com/innovation/cooling-fabric-with-chalk-based-coating