Riding in car with smoker can damage your health, new study claims

According to the research, non-smoking passengers showed elevated levels of butadiene, acrylonitrile, benzene, methylating agents and ethylene oxide, which are "thought to be the most important among the thousands in tobacco smoke that cause smoking-related disease," senior investigator and UCSF professor Dr. Neal L. Benowitz said in a university press release.

“Ours is the first study to measure exposure to these particular chemicals in people exposed to secondhand smoke,” Benowitz said. “This indicates that when simply sitting in cars with smokers, nonsmokers breathe in a host of potentially dangerous compounds from tobacco smoke that are associated with cancer, heart disease and lung disease.”

According to the university release, the study looked at 14 non-smokers who each sat for one hour in the right rear seat of an SUV while a smoker sat in the driver’s seat. The driver then smoked three cigarettes over the hour’s time while the front and rear windows were cracked open about four inches.

After 8 hours, urine samples from the nonsmokers were compared to samples taken from before the experiment. According the research, seven biomarkers showed a “significant increase” following exposure to secondhand smoke.

"This tells us that people, especially children and adults with preexisting health conditions such as asthma or a history of heart disease should be protected from secondhand smoke exposure in cars," said lead author Dr. Gideon St. Helen.

Researchers cautioned that the study conditions may not be representative of real-world driving situations, as the study was conducted in a stationary vehicle which may not provide as much ventilation as a moving car.