A team of researchers from Harvard and Rochester Universities believe the reason to be because smoke seeps through the walls and shared ventilation systems which are present in flats.
Researchers conducted the study on children living in households where nobody smokes, finding that 73 per cent of the 5,000 children analysed were exposed to second hand tobacco smoke.
Author of the study and associate professor of paediatrics at Harvard Medical School Dr Jonathan Winickoff, said: “If your neighbours are smoking then you are exposed if you live through the wall in a semi-detached house. In apartment buildings this effect is magnified. Smoke contaminates the whole building.”
Martin Dockrell, director of policy and research at the UK group ASH, said: “There is a strong case for social and private sector landlords designating some entire blocks as smoke-free to respect the choice and the health of the great majority of their tenants.”
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