In Hong Kong, one in every five adults is a smoker. According to research, smokers drag smoke from each cigarette they light on average ten times, and smoking takes only 20 seconds, leaving about ten minutes while a cigarette is burning that its smoke is released into the air surrounding the smoker. This side smoke affects other people like non-smokers who are subject to inhaling both the smoke of a burning cigarette ¡Ð and the smoke that smokers exhale.

The concentration of poisonous substances in the side stream smoke is even higher than that of the main smoke. For example, nicotine concentration in side stream smoke is two times higher, tar stimulants are three times higher, carbon monoxide is five times higher and tar carcinogens are 50 times higher.

These substances are harmful. Nicotine heightens blood pressure and increases the heart beat ¡Ð and the tendency to develop blood clots or thrombosis.

Carbon monoxide hampers the transmission of oxygen, reducing the absorption of oxygen by the body and thereby lowering stamina while speeding up the ageing process.

The tar found in cigarette smoke contains 43 types of carcinogens which are known to irritate the respiratory tract, increase bronchial tree secretion and coughing, reduce the ability of the cilia to remove foreign objects from the lungs, thus increasing the chances of chest infection.

When a non-smoker stays in a room in which 20 cigarettes have been smoked, he or she will have inhaled the smoke equivalent to one cigarette

As a result, passive smokers' health is subject to damage. According to research, when a non-smoker stays in a room in which 20 cigarettes have been smoked, he or she will have inhaled the smoke equivalent to one cigarette.

American research has found that the life expectancy of women with smoking spouses was four years less than those who were married to non-smokers. Moreover, children with smoking parents have two to three times higher rates of bronchial illnesses and are more likely to imitate their parents' smoking habits.

Additionally, harmful substances from nicotine and carbon monoxide absorbed by non-smoking pregnant mothers from a spouse's side stream smoke enter into the placenta through the blood steam and can affect the absorption of nutrition by the foetus and consequently its normal growth. Second hand smoke is known to be the cause of miscarriages, low birth weight or premature death in babies.

Outside the home, American research has found that the degree of damage to the lungs of passive smokers in the workplace was equivalent to that of smokers who had smoked an average of ten cigarettes a day for two years.

The message is that smokers are not only damaging their own health ¡Ð but also the health of members of their families, colleagues and friends. So non-smokers should not hesitate to voice their opinion against smokers infringing on their "territory"