Feb. 6, 2012 -- Secondhand smoke exposure in cars declined among U.S. middle and high school students between 2000 and 2009.
The number of young people who reported riding in a car with someone who was smoking cigarettes "within the past seven days" during the study period fell from about 48% to nearly 30% over a 10-year period, a new study shows.
This downward trend in secondhand smoke exposure was seen across all ages of middle and high school students, genders, and ethnic groups.
During this stretch of time, the number of teens who were nonsmokers rose. Kids who said they had not had a cigarette within the last 30 days went from a low of about 80% in 2000 to a high of about 88% in 2009.
For the study, published online in the journal Pediatrics, researchers analyzed data collected for the National Youth Tobacco Survey. American students in grades six through 12 from public, private, and Catholic schools across the country completed the survey five different times during a 10-year span. Between 18,000 and 27,000 students participated.
The researchers admit that considerable progress has been made over the last decade in reducing students’ exposure to secondhand smoke while in cars. Still, they found that nearly 23% of nonsmoking students had breathed in secondhand smoke in motor vehicles in the week leading up to the survey.
"Enhanced and sustained efforts are needed to further reduce secondhand smoke exposure in this environment," the researchers say.
They credit smoke-free laws in restaurants, bars, public buildings, and workplaces with helping to clear the air. These bans mean that kids come in contact with nicotine and other dangerous particles from a burning cigarette less often and in lesser amounts.
People's attitudes toward smoking around children have also changed, and fewer Americans are taking up the smoking habit.
Other studies have suggested that young people who are more frequently around secondhand smoke have more respiratory infections, middle ear problems, and severe asthma.
In an enclosed space like a car, kids are particularly vulnerable when parents or peers smoke. It's hard for them to avoid tobacco-burning products in a motor vehicle during a period of their lives when their lungs, immune, and nervous systems are still developing.
That's why the American Academy of Pediatrics has said there is no safe level or length of secondhand smoke exposure for children. The organization has called for smoke-free environments in homes, cars, schools, workplaces, and play areas.
Although the home is the most common place for young people to breathe in secondhand smoke, less is known about exposure in vehicles, until now. Only four states in the U.S. -- Arkansas, California, Louisiana, and Maine -- along with Puerto Rico have passed laws banning smoking inside cars when children are passengers.
"The implementation of a smoke-free motor vehicle policy represents the most effective way to protect youth from secondhand smoke exposure in this environment," conclude the researchers.