Annotation Indian J Pediatr 1996; 63 : 139-141 I i Impact of Passive Smoking I t has been well known for over 3 dacades that smoking is a health hazard. In 1964 causal relationship between smoking and cancer of larynx and lung was reported 1. Smoking has been linked to cardiovascular disease, stroke, obstructive airway disease, pregnancy complications and a variety of neoplasms 2. Recently it has been shown to be associated with increased incidence of cataract and rapid progression of, in HIV positive persons, to clinical acquired immunodeficiency syndrome (AIDS) 3. The growing menance of tabacco smoking is evident in the developing countries also where there has been a recent upsurge in the number of young smokers. The magni- tude of the problem is highlighted by a WHO report which states that about one bllIion smokers are smoking 5 trillion ciga- rettes annually causing 3 million deaths (2 million in developing countries) 4. It is esti- mated that over the next 40 years the an- nual number of deaths due to tobacco smoking will escalate from 3 million to over 10 million s. It is disturbing to note that more and more women are taking up this habit either to demonstrate their equality with men or as a sign of liberation. Indeed, threat posed by tobacco smoking has reached alarming proportions globally and the present day concern centres around the damage caused not only to the smokers but also to the innocent passive smokers. The term passive smoking or in- voluntary smoking is defined as the expo- SUre of non-smokers to tobacco smoke of Smokers in an enclosed environment. MECHANISM OF PASSIVE SMOKING Tobacco smoke is a major source of do- mestic air pollution and it consists of main stream and side stream smoke. The main stream smoke is an aerosol mixture in- haled by the smokers, filtered in their lungs and exhaled. Side stream smoke is the aerosol emitted directly from the lit end of a burning tobacco product.~The chemical components of the two types of smoke include; nicotine, carbon monoxide, oxides of nitrogen and various carcino- gens and co-carcinogens. However, undi- luted side stream smoke has 2.5 times more carbon monoxide, 52 times more dimethyl- onistrosamine and 73 times more ammo- nia. If a cigarette is smoked in an average size room, 85% of the smoke generated consists of side stream smoke which be- comes diluted in a large volume of air. There- fore, the passive smoker inhales a compar- atively lower concentration of chemicals 6. IDENTIFICATIONOF CHILDREN AT RISK OF PASSIVE SMOKING The assessment of involuntary exposure of infants and children of environmental to- bacco smoke has been unsatisfactory. It has multiple determinants such as : (i) The actual duration of time that a person smokes in the presence of the child. (ii) The number of cigarettes and the number of smokers at any given time. (iii) Environmental charac- teristics such as temperature, humidity, ventilation etc. (iv) The type of tobacco prod- uct smoked i.e. cigarette, bzdi, Huka etc. The majority of Indians live in over- crowded, poorly ventilated homes which make matters worse for the passive smok- ers. The quantification of continine in plasma, saliva and urine is accepted as a reliable marker of chronic exposure to to-