The findings, published in the Nicotine and Tobacco Research Journal, provide evidence for extremely high level of SHS exposure in the Bangladesh capital Dhaka.
This widespread SHS exposure is likely to be due to the high prevalence of male smoking in Bangladesh, the study reports.
The adult prevalence of tobacco uses and smoking is 35.3% and 18% in Bangladesh, respectively, despite the country introduced laws prohibiting smoking in public places.
The smoking is widespread in public places due to weak implementation of the laws.
With this backdrop, the research team conducted the survey of 1368 children aged 9-14 from 34 primary schools in Dhaka to assess their exposure to SHS.
To measure the exposure, they tested their saliva to see if it contained cotinine. They examined the association between the adult smoking behaviours of residents and visitors at homes and salivary cotinine levels in children in both cities.
Compared to children living with non-smokers, those living with adult smokers had higher levels of SHS exposure. Similarly, children living in houses permitting indoor smoking had slightly higher levels of SHS exposure than those where smoking was not permitted.
The extent of SHS exposure indicates unrestricted smoking, both in public and private places.
"It is important to advocate for smoke-free homes and cars to protect children from SHS exposure. However, in addition to these initiatives, it is also important to enforce smoking bans in public places and transportation, especially those public spaces that children frequently visit, such as playgrounds, parks and fairgrounds. It is essential to complement smoking restrictions with tobacco cessation advice and support in these settings" said Professor Kamran Siddiqi, from University of York, UK, and the Chief Investigator of the study.
"This research findings are really alarming. If we cannot protect the children from SHS exposure, they will develop increased risk of respiratory infections and associated deaths, and will be at risk of lower academic performance and a high rate of smoking uptake in later life", said Professor Rumana Huque, from ARK Foundation, and a co-author of the paper.
The research team called for a comprehensive approach to protect the children from this harm, smoking restrictions in households and enforcement of smoking bans in public places.
