As you know, I try to give you the best, most scientific answer whether I think you will like it or agree with it or not. And I insist that scientific studies be of high quality. This subject is fraught with researchers who have sold their integrity for research dollars. That appears to be the case with all studies I have seen that claim that second hand smoke is more dangerous than first hand smoke. The two largest studies are the UN study that incredibly said that second hand smoke was not dangerous at all I can not a...

As you know, I try to give you the best, most scientific answer whether I think you will like it or agree with it or not. And I insist that scientific studies be of high quality. This subject is fraught with researchers who have sold their integrity for research dollars. That appears to be the case with all studies I have seen that claim that second hand smoke is more dangerous than first hand smoke. The two largest studies are the UN study that incredibly said that second hand smoke was not dangerous at all I can not address because I have not seen enough of it. The other study appeared in the British Medical Journal (BMJ) and was based on research by James Enstrom, from the University of California, and Geoffrey Kabat, from the State University of New York. They analysed data from the American Cancer Society's (ACS) Cancer Prevention Study, which was started in 1959 and ended in 1998. In total 118,094 Californian adults had been studied, and Enstrom and Kabat focused on the 35,561 nonsmokers who were married to partners who smoked. The statistical analysis is excellent. The objections are that in 1959 lots of people were exposed to second hand smoke whether married to a smoker or not. And the research was funded in part by the tobacco industry. This last is a valid objection. The first is grasping at straws, I think. And it did find that second hand smoke is dangerous. Just not as dangerous as the hype. Therefore making smoking an outside activity or in a vented room seems warranted. Other measures are overkill.

The health risks of smoking are not uniform across all smokers. Risks vary according to amount of tobacco smoked, with those who smoke more at greater risk. Light smoking is still a health risk.

Passive or involuntary smoking occurs when the exhaled and ambient smoke from one person's cigarette is inhaled by other people. It involves inhaling carcinogens, as well as other toxic components, that are present in second...

The health risks of smoking are not uniform across all smokers. Risks vary according to amount of tobacco smoked, with those who smoke more at greater risk. Light smoking is still a health risk.

Passive or involuntary smoking occurs when the exhaled and ambient smoke from one person's cigarette is inhaled by other people. It involves inhaling carcinogens, as well as other toxic components, that are present in secondhand tobacco smoke. PASSIVE smokers inhale the equivalent of just six cigarettes a year from other people's smoke; according to the largest ever study of actual exposure levels of non-smokers.

Secondhand smoke is also known to harm children, infants and reproductive health through acute lower respiratory tract illness, asthma induction and exacerbation, chronic respiratory symptoms, middle ear infection, lower birth weight babies, and Sudden Infant Death Syndrome. Infants who die from SIDS tend to have higher concentrations of nicotine and cotinine in their lungs than those who die from other causes.

The figure, which undermines previous warnings about the dangers of passive smoking, is a thousand times lower than that faced by direct smokers, and so tiny that it could not be measured statistically.

Passive smokers who live and work with smokers are typically exposed to just 0.1 per cent of the dangerous components of cigarette smoke inhaled by smokers. Passive smokers face a tiny excess lung cancer risk of around two per cent - 10 times lower than suggested by either the statistical evidence or estimates based on cotinine levels - a chemical linked to nicotine - in passive smokers.

KEY POINTS:

Passive smoking is the act of breathing in secondhand smoke.

Tobacco smoke contains over 400 chemicals, and over 60 are known or suspected to be carcinogenic (cancer-causing).

A controversial study published in the British Medical Journal appears to show that in non-smokers regularly exposed to smoke via their spouses were not at significant risk of cancer or heart disease.

Despite the finding, the study has been strongly criticised, with a multitude of flaws highlighted.

Experts contend that the dangers of passive smoking are well documents and cite existing evidence from more than 50 studies.

According to Cancer Research UK, passive smokers are 20 to 30 per cent more likely to develop lung cancer than people not exposed to smoke, with several hundred deaths occurring as a direct result in the UK each year.