The degree of secondhand smoke that finds its way from public places into the home has not been affected by the smoking ban in Wales.
A study of 3500 children from 75 primary schools in Wales, published in the open access journal BMC Public Health
, found that they were exposed to similar amounts of secondhand smoke before and after legislation, which should reassure those worried that exposure to smoking at home could increase following the ban.
Dr Jo Holliday and colleagues at Cardiff University's School of Social Sciences carried out the study, funded by the Welsh Assembly Government. They measured the levels of cotinine, a marker of exposure to cigarette smoke, in the saliva of approximately 1750 year 6 children before and after the ban, as well as asking the children about their experiences of passive smoking. Holliday said, "Concerns have been expressed regarding the potential displacement of smoking from public places into the home, affecting non-smokers and, in particular, children. We found that the smoke-free legislation in Wales did not increase second-hand smoke exposure in homes of children aged 10-11. Nevertheless, the home did remain the main source of children's exposure".
The researchers point out that the measured levels of passive smoking still represent a public health concern. According to Holliday, "Almost 40 percent of children had a cotinine concentration above 0.17ng/ml, a level associated with lung dysfunction, and almost six percent of children had salivary cotinine concentrations higher than those of non-smoking Scottish bar workers prior to the introduction of similar legislation in Scotland".