WASHINGTON, Nov.23,2017-- Only 23 of the world's 50 busiest airports, including five of the 10 busiest airports, completely prohibit smoking indoors, a new study by the U.S. Centers for Disease Control and Prevention (CDC) said Wednesday.
The other 27 airports continue to allow smoking in designated or ventilated indoor areas, according to the study in the CDC's Morbidity and Mortality Weekly Report.
This means air travelers and employees at 46 percent of the world's busiest airports are protected from exposure to secondhand smoke, it said.
It's CDC's first assessment of smoke-free policies in the world's airports. More than 2.7 billion passengers annually pass through the airports included in the study.
"There is no risk-free level of secondhand smoke exposure," Corinne Graffunder, director of CDC's Office on Smoking and Health, said in a statement. "Even brief exposure can have health consequences."
Among the top 10 busiest airports, five that had a smoke-free policy are Beijing Capital, Chicago's O'Hare International, London's Heathrow, Los Angeles International, and Shanghai Pudong International, said the study, which assessed policies in 2017.
The other five that allowed smoking in certain indoor areas are Atlanta Hartsfield Jackson International, Dubai International, Hong Kong International, Paris's Charles de Gaulle, and Tokyo International.
Regional differences were also observed in smoke-free policy status among the world's 50 busiest airports.
Among those in North America, 14 of 18 had a smoke-free policy, and in Europe, four of nine had a smoke-free policy, including airports in Madrid, Barcelona, and London.
In Asia, four of 22 had a smoke-free policy, all of which are in China, including Beijing Capital International Airport, the world's second busiest airport.
The only airport among the 50 busiest in Oceania is Sydney International, which is smoke-free.
None of the world' s 50 busiest airports is located in South America or Africa.
Previous studies have documented that secondhand smoke can transfer from designated smoking areas into nonsmoking areas in airports, where nonsmoking travelers and employees can be exposed, the CDC said.
As a result, travelers and workers are at risk of secondhand smoke exposure in these airports, it noted.
Exposure to secondhand smoke from burning tobacco products causes premature death and disease, including coronary heart disease, stroke, and lung cancer among nonsmoking adults, according to the U.S. agency.
In children, it can cause sudden infant death syndrome, acute respiratory infections, middle ear disease, exacerbated asthma, respiratory symptoms, and decreased lung function, the CDC said.