Tobacco smoking, now and in the past, has been a custom and addiction primarily of men, leaving women and children as the majority of the world’s passive, or involuntary, smokers [1]. Passive smoking is the combination of “side stream” smoke given off by a burning tobacco product and “mainstream” smoke exhaled by smoker [2,3]. Exposure to passive smoking can take place in the home, the workplace or other environments that are accessible to the public (e.g. bars, public transport). Cigarette smoking is the main source of SHS exposure, because it is the most prevalent form of tobacco smoking, although specific patterns differ between countries. Tobacco smoke contains thousands of chemicals that are released during burning as gases, vapors and particles. Mainstream smoke emitted as SHS is composed primarily of carbon monoxide (3–11%), particles (15–43%) and nicotine (1–9%) [4,5]. India has one of the largest populations of smokers in the world. Findings from the 2009/2010 Global Adult Tobacco Survey (GATS) indicate that there were 110 million smokers in the country, with 16% of males smoking bidis and 10% smoking cigarettes. Over half (52.3%) of adults report exposure to SHS at home, with marked state-level variation (9.9–96.5%). Exposure to second-hand smoke (SHS) is higher in rural than urban areas (58.0% versus 38.5%) and in lower socioeconomic status households [6]. To protect non-smokers from SHS, India implemented national legislation (Section 4 of the Cigarettes and other Tobacco Product Act 2003) prohibiting smoking in public places and workplaces in October 2008 [7]. The relationship between exposure to passive smoking and many health outcomes in children and adults has been cross checked closely in the epidemiological and experimental literature. Reviews of the literature have been published by national and international organizations as well as by researchers in the field. This study was done to estimate the prevalence of passive smoking and to know the participants awareness regarding ill effects of passive smoking among Medical college undergraduate students in Mangalore.

The present study was a cross sectional study, conducted to assess the prevalence of exposure to passive smoking and to know the awareness regarding ill effects of passive smoking among Medical college undergraduate students in

54.5% participants close friends were smokers, 96.25% participants exposed to passive smoking in public space in last thirty days (Fig-1). 42. 3% replied passive smoking causes serious health hazard, 2.8% told not at all a health hazard among them. Majority told (81.3%) it causes lung cancer, 13.7% students told they don’t know the ill effects of SHS (Fig- 2).

Table 1: Showing smoking status of participants

Table 2: Showing smoking status of house-hold Members and Peers

Table 3: Showing indirect determinants of Passive smoking

Observations that exposure to passive smoking has not decreased significantly since the ban came into effect suggests that efforts are still needed to address this issue. The study also provides evidence that about 94.4% students reported inside their hostel smoking is not allowed (2.5% males, 91.9% females) but more than half (61.5%) of the students exposed to passive smoke in hostel daily. Among daily hostel exposure history, males were 88.8%, females were 29.3%. This data highlights the urgent need to implement strict rules and regular surveillances in hostel premises. Raute, et al [14] concluded in their study that the majority of students (88.1%) were aware about the harmful effects of being exposed to tobacco smoke from other people. Our study highlights, 96.0% students were aware of exposure to passive smoking causes health hazard among non smokers. John Tayu Lee et al[15] found out that 61.7% women , 54.1% men’s reported their homes are smoke free. Unlike this study variation we found higher number of houses were smoke free i.e. 91.6% boys, 90.6% girls homes are smoke free. With respect to exposure in our study almost 8.75% students exposed passive smoking at home. 96.25% in public space and about 81.8 % students exposed to passive smoking outside their home or hostel or residence in the past thirty days, Similar study by Raute et al [14] reported that about 16.5% of students were exposed to passive smoking at home, and 39.9% outside of the home.

Since data was collected by self administered questionnaire. Smoking history by students especially girls , and participants close friends, house hold smoking status, and also exposure of passive smoking in hostel may not be accurate; our findings may well have underestimated the scope of the problem if respondents were reluctant to acknowledge their smoking status. The study was limited to Medical students in the age group 18 -26 years. the findings of this study, especially in Knowledge of passive smoking cannot necessarily be generalized to other non medical students in this age group, nor to illiterates and to general public.

Self-reported smoking status, parents’ smoking habits, close friends’ smoking, and participants’ residence were the significant determinants of exposure to passive smoking at home and outside