A study by the Centers for Disease Control and Prevention (CDC) has suggested that though in the United States most middle and high school students have never smoked tobacco nearly 50% of this group of never-smokers has exposure to secondhand smoke.

The findings belonged to the 2013 CDC National Youth Tobacco Survey, which included over 18,000 adolescents from grades 6 to 12 in public and private schools countrywide.

The students were asked to fill written questionnaires regarding whether they have used tobacco products such as pipes, hookahs, cigarettes, e-cigarettes, and chewing tobacco.

To assess the secondhand smoke exposure, the survey asked students whether they had been around somebody in the past week who smoked tobacco in their home, at school or other public places. The survey didn’t ask whether the students were around people using e-cigarettes.

In the group of adolescents that said they never used tobacco, 48% had been around secondhand smoke in the last seven days. The survey found that the most common places for exposure were public areas like parks and restaurants, where nearly 35% of the participants reported being exposed. Other 17% and 27% participants got exposed at school and work, respectively.

Though just 15% participants got exposed in their home and other 15% in cars, these were the most common areas for everyday secondhand smoke exposure.

Brian King, deputy director for research translation in the CDC Office on Smoking and Health, said, “The findings reinforce that secondhand smoke is still a problem in this country. Half of middle school and high school students are exposed to something we know is harmful to their health and is completely preventable”. Led by King, the research was carried by the journal Pediatrics on Monday.