World No Tobacco Day 2024: How passive smoking puts non-smokers at risk

Lung cancer is caused by a similar mechanism in passive smoking as in active smoking. (Image: Canva)

World No Tobacco Day 2024: The accidental intake of smoke by non-smokers who are in close proximity to active smokers is sometimes referred to as passive smoking, or second-hand smoke. Both the burning end of a cigarette and the smoke that smokers exhale produce this kind of smoke. Since passive smoking exposes people to the same dangerous compounds as active smoking (including over 7,000 damaging substances), it is a serious public health concern. Several of these substances are recognised carcinogens, meaning they can cause lung cancer among other health problems.

Passive smoking is a serious risk to public health in India, where it may be a factor in millions of deaths from lung, heart, and other diseases associated with smoking each year. In addition, the residual pollution known as thirdhand smoke, which remains in places where smoking has taken place, contains over 250 dangerous compounds that can be hazardous to one's health.

Understanding passive smoking

When non-smokers are around tobacco smoke from active smokers, it's known as passive smoking. This exposure can occur in a variety of locations, including cars, offices, public spaces, and homes, Says Dr Gagan Saini – senior director, radiation oncology, Max hospital, Vaishali

Passive smoke is mostly composed of two elements

Sidestream smoke: This refers to the smoke released by the tip of a pipe, cigar, or cigarette.

Mainstream smoke: The smoke that a smoker exhales.

Hazardous substances found in both forms of smoke include ammonia, benzene, formaldehyde, tar, nicotine, and carbon monoxide. For nonsmokers, passive smoking poses major health concerns, particularly if exposure occurs frequently or for extended periods of time.

How passive smoking causes lung cancer

Lung cancer is caused by a similar mechanism in passive smoking as in active smoking. The same toxins found in tobacco smoke are also inhaled by non-smokers when they inhale second-hand smoke. Lung cancer is caused by passive smoking in the following ways according to Dr Saini.

Inhalation of carcinogens: The carcinogens in second-hand smoking have the potential to harm lung cells' DNA. Mutations that can result in malignant growths are more likely to occur when these carcinogens are exposed to repeatedly.

Chronic inflammation: The toxins in second-hand smoking have the potential to harm lung tissue and create inflammation in the airways. One identified risk factor for the onset of cancer is chronic inflammation.

Oxidative stress: The body experiences more oxidative stress as a result of passive smoking, which can cause cellular damage and the emergence of cancer.

Diminished immune reaction: Tobacco smoke exposure can impair immunity, which makes it more difficult for the body to fight off illnesses like cancer.