Travelling in a smoker's car for just ONE HOUR can damage your health

Travelling in a car with a smoker for just one hour can damage a person's health, exposing them to dangerous levels of toxic chemicals, new research warns.

Non-smokers exposed to secondhand smoke from three cigarettes while in the car showed increased levels of carcinogens and other toxins in their urine.

Scientists at the University of California said their findings indicate secondhand smoke in cars and other vehicles poses a potentially major health risk.

The passengers showed raised levels of butadiene, acrylonitrile, benzene, methylating agents and ethylene oxide.

This group of toxic chemicals is 'thought to be the most important among the thousands in tobacco smoke that cause smoking-related disease,' said senior investigator Professor Neal Benowitz.

He said: 'Ours is the first study to measure exposure to these particular chemicals in people exposed to secondhand smoke.

'This indicates that when simply sitting in cars with smokers, non-smokers breathe in a host of potentially dangerous compounds from tobacco smoke that are associated with cancer, heart disease and lung disease.'

The researchers analysed 14 non-smokers, who sat in the right rear passenger seat of a car, behind a smoker in the driving seat.

In an hour the smokers smoked three cigarettes, while the front and rear windows were opened around four inches.

Before being exposed to the smoke, and then eight hours afterwards, the non-smokers' urine was examined for biomarkers of nine chemical compounds found in cigarette smoke.

The chemicals are all associated with cancer, cardiovascular disease and respiratory diseases.

Seven biomarkers showed a significant increase following exposure to secondhand smoke. 

The study's lead author, Dr Gideon St Helen, said: 'This tells us that people, especially children and adults with pre-existing health conditions such as asthma or a history of heart disease should be protected from secondhand smoke exposure in cars.'

But the team did offer some caution. They said the research might not represent smoking in most cars because the stationary vehicle used in the research would provide less ventilation than a moving car. 

Dr St Helen added: 'Nonetheless, the air samples we took were similar in makeup to those seen in previous smoking studies that used closed cars and cars with different ventilation systems in operation'

'And so we believe that the general levels of risk to nonsmokers that we present is realistic.'

The study was published in the journal Cancer, Epidemiology, Biomarkers & Prevention published by the American Association for Cancer Research.