Secondhand smoking, breathing in of environmental tobacco smoke (ETS), is also called passive smoking. It is when a person breathes in smoke given off into the environment by other people.

Secondhand smoke or ETS is a combination of side stream smoke coming straight from the burning tobacco and the mainstream smoke that is exhaled by the smoker. It comprises of over 4000 chemical constituents, a large proportion of which are the inducers of respiratory illnesses and around 40 are known or suspected carcinogens.

The US Environmental Protection Agency (EPA) has classified ETS as a class A (known human) carcinogen along with other known carcinogens such as arsenic, asbestos and benzene etc.

ETS is unfiltered, thus the levels of carcinogens in it are much more than in smoke inhaled directly by an active smoker. Smoking of a cigarette produces smoke from two major places, mainly from the tip of cigarette and from the rest of the cigarette as the hot vapors liberated through the cigarette and its filter.

About 70% to 80 % of ETS is from the burning tip of cigarette and comprises of the highest levels of nicotine, carbon monoxide, tar and various other carcinogens. Therefore, a constant exposure to an ETS is apparently even more injurious than directly smoking a cigarette for an equivalent period. Effects of Exposure to Secondhand Smoke

Immediate effects:

Immediate effects of secondhand smoking comprise of eye irritation, cough, sore throat, headache, nausea and dizziness.

Long-term effects:

Lung cancer: The major cause of lung cancer among non-smokers is secondhand smoke. One of the studies revealed that hospitality workers who were exposed to secondhand smoke became three times more prone to lung cancer.

Cardiovascular problems: ETS can induce short-term and long-term harm to the heart by decreasing its functional capacity and lowering the capacity of blood to carry oxygen. Some of the chemicals in secondhand smoke can block or harden the arteries, causing problems like atherosclerosis, hypertension and later heart attack. In one of the studies, it was found that secondhand smoking enhances the risk of a heart attack by at least two times.

Stroke: Non-smokers exposed to secondhand smoke run at least 80% more risk of stroke than do the non-exposed people.

Asthma: One of the studies revealed that the non-smokers exposed to ETS at work showed at least twice the risk of asthma than the non-exposed people did. Those who were exposed to ETS at home as well, showed as much as five times greater risk for asthma than the non-exposed people did. In individuals who already suffer from asthma, exposure to ETS can significantly decline their lung function. Breast Cancer: Some of the recent studies have revealed ETS to increase the risk of breast cancer among women.

Effects on the fetus:

Smoking by a pregnant woman can have various serious consequences on the developing fetus.

• Babies born to women who smoked during their pregnancy have a low birth weight and are often born prematurely.

• Their organs, chiefly the lungs, are smaller than of other babies and these babies are more susceptible to cot death.

• They are more prone to illness all their life and are more likely to become addicted to the tobacco later in their life.

Effect on Children

• Kids that are exposed to secondhand smoke from either parent during the first year of their lives are far more likely to be afflicted with asthma, pneumonia, bronchitis, bronchiolitis and other respiratory problems than kids who were not exposed.

• Secondhand smoking may also predispose children to the impairment of the blood circulatory system, behavioral problems and olfactory (nasal) problems.

• It also increases their susceptibility to develop cancer during their adulthood.