As the weather gets warmer, many parents will turn to pools to keep their family cool. Due to their low cost and ease of use, portable pools - which include wading¹ pools, inflatable（可充气的） pools and soft-sided, self-rising pools - have become an increasingly popular alternative to expensive in-ground pools or water park visits. While portable pools can be a great way for children to cool off during hot summer days, a new study conducted by researchers at the Center for Injury Research and Policy of The Research Institute at Nationwide Children's Hospital has found that these pools may be more dangerous than many parents realize. The study, which was released online today and will appear in the July 2011 print issue of Pediatrics, found that every five days a child drowns in a portable pool during the summer in the United States. The majority of cases in the study, which looked at both fatal and non-fatal submersion（淹没） events, involved children under 5 years of age (94 percent), involved males (56 percent), involved pools in the child's own yard (73 percent) and occurred during the summer months (81 percent).

"Because portable pools are generally small, inexpensive and easy to use, parents often do not think about the potential dangers these pools present," said Gary Smith, MD, DrPH, senior author of the study and director of the Center for Injury Research and Policy at Nationwide Children's Hospital. "It only takes a couple of minutes and a few inches of water for a child to drown. It is important for parents to realize that portable pools can be just as dangerous as in-ground pools."

It is also vital that parents realize that while supervision² by an adult when children are in a pool is important, it is not enough. More than 40 percent of the children in this study were being supervised by an adult at the time of the submersion event. In 18 percent of cases, a brief lapse³（失效） in supervision, such as socializing with neighbors, answering the telephone and doing chores, was enough to allow a submersion event to occur.

The study's authors emphasize that multiple layers of protection should be used to prevent portable pool submersions, including measures to prevent children from accessing pools when adults are not present, keeping children safe during use and being prepared to respond if a submersion injury does occur.

A hurdle⁴ that parents face is the relatively⁵ high cost or lack of availability of drowning prevention tools such as isolation⁶ fencing, safety covers, lockable or removable ladders and pool alarms specifically designed for portable pools.

"Drowning prevention tools used for in-ground pools are often either too expensive or simply not available for portable pools," said Dr. Smith, also a professor of Pediatrics at The Ohio State University College of Medicine. "Portable pool manufacturers should develop more effective and affordable⁷ tools to help parents decrease the drowning hazards associated with these products."