The heat waves that have scorched many parts of the world this summer may become all too familiarclimate scientists say they are likely to occur with increasing frequency. When air-conditioning is not an option for relief,an electric fan may seem like the best alternative. But some experts have questioned whether electric fans might actually hamper efforts to cool down. In a new study,a team of researchers based primarily in Britain sought to review evidence on the effectiveness of electric fans during heat waves that have occurred all over the world. Despite what many people think,most fans do not directly cool the ambient air. When placed in an open window,they pull in cooler air from outside. But there is a point at which their effectiveness may diminish. When temperatures climb past 95 degrees,having a fan pointed at you can actually contribute to heat gain,not reduce it. At those temperatures,being directly in the path of hot air blown from a fan can raise the risk of dehydration. The researchers said that while they could not support or recommend against the use of electric fans in sweltering conditions,it was important to consider their potential harms and benefits. That is especially the case for vulnerable populations like the elderly,who are less able to cool down through sweating or increasing the flow of blood to their skin, the authors wrote.
