“…12,22,* Under such circumstances, substantial and consistent declines in SHS exposure are found across indicators, including those from observational studies, 7,23 surveys of self-reported SHS exposure, 7,12,24 biomarkers of SHS exposure, 7,24,25 and air quality assessments. 7,8 Nevertheless, and despite enjoying high levels of popular support, the implementation of smoke-free laws in low- and middle-income countries may encounter difficulties that stem from such factors as greater social acceptability of tobacco use, shorter histories of programs and policies to combat tobacco-related diseases, and a greater tolerance of law breaking.…”