Background:
While smoke-free policies in most European countries are established for public places, private areas are mainly not regulated and may represent an important source of second-hand smoke exposure. We aimed to describe and characterise smoking rules in homes and cars of smokers from 6 European countries.

Methods:
We used data from the first wave (2016) of the International Tobacco Control (ITC) 6 European Country Survey, part of the EUREST-PLUS Project, in representative national samples of adult (18+ years) smokers in Germany, Greece, Hungary, Poland, Romania and Spain (1000 in each country). We analysed questions about smoking rules in smokers' homes and cars with children and differentiated among: no rules, partial (allowed in some rooms or under special circumstances) and total ban (smoke-free homes and cars). We computed the prevalence (%) of homes and cars according to the rules, and used Poisson regression models to identify factors associated with total smoking ban. We incorporated weights from the complex sample design.

Results:
In homes, more smokers opted for partial ban rather than for a total ban. The highest and lowest proportions of smoke-free homes were found in Hungary (35.5%) and Spain (13.1%), respectively, while partial ban prevalence ranged from 41.3% (Spain) to 49.9% (Greece). The proportion of smoke-free cars with children was overall higher compared to homes, ranging from 51.8% (Greece) to 67.7% (Germany). Having moderate or high level of education, presence of children, smoking less than 10 cigarettes per day and having previous attempts to quit smoking were positively associated with total smoking ban in homes and cars.

Conclusions:
European smokers tend to opt for partial smoking ban at homes and for total ban in cars with children. Prevalence of smoke-free homes is relatively low and further legal and educational enforcement is needed to promote smoke-free environments.
Funding: EC Horizon2020 HCO-6-2015 (EUREST-PLUS No. 681109).