Despite efforts made by the government to cut the rate of secondhand smoke exposure, the problem remains for almost half of non-smoking middle school and high school children.

Earlier studies linked secondhand smoke to different diseases. As HNGN previously reported, children exposed to secondhand smoke tend to grow up with thickened arteries and increased risk of heart attack and stroke. Last year, the U.S. Centers for Disease Control and Prevention (CDC) released a report highlighting a significant (50 percent) drop in secondhand smoke exposure between 1999 to 2000 and 2011 to 2012. The researchers credited the improvement to policies that banned smoking in bars, restaurants and offices.

However, a new study published on Monday in the journal Pediatrics shows that the battle against secondhand smoke remains. The survey was answered by 18,406 middle school and high school students from the United States. They were asked about their exposure to secondhand smoke from homes, cars, school, work and public areas. Almost half or 48 percent of the nonsmokers said they were exposed to secondhand smoke, more than 15 percent at home, 17 percent at school, 27 percent at work and 35 percent in other public areas.

"These findings are concerning because the U.S. surgeon general has concluded that there is no safe level of secondhand smoke exposure," Israel Agaku, lead author and a researcher at the Centers for Disease Control and Prevention, told the Washington Post.

The findings of the study can be used in the development of new policies and reinforcement of existing policies aiming to protect the nonsmokers from the dangers of secondhand smoke exposure.