‘Average air pollution levels from second-hand smoke directly outside designated smoking areas in [US] airports are five times higher than levels in smoke-free airports,’ according to a Newswire story quoting a study by the Centers for Disease Control and Prevention.
This seems to imply that there is second-hand smoke in smoke-free airports, but might be meant to mean that the presence of second-hand smoke directly outside designated smoking areas in US airports raises the general air pollution levels there to five times the level of general air pollution levels in smoke-free airports.
The study conducted in five large hub US airports showed also that air pollution levels inside designated smoking areas were 23 times higher than levels in smoke-free airports.
In the study, designated smoking areas in airports included restaurants, bars, and ventilated smoking rooms.
Five of the 29 largest airports in the US allow smoking in designated areas that are accessible to the public: Hartsfield-Jackson Atlanta International Airport, Washington Dulles International Airport, McCarran International Airport in Las Vegas, Denver International Airport, and Salt Lake City International Airport.