DENVER (CBS4) – Travelers at Denver International Airport are at a higher risk than most other airports for dangerous exposure to secondhand smoke, according to a new survey from the Centers for Disease Control and Prevention.

The survey found air pollution is five times higher outside smoking rooms than in smoke-free airports. Pollution levels inside the smoking areas are 23 times higher.

DIA is one of five major airports in the U.S. that still allows indoor smoking.