Altogether 110 measurements in 57 venues with smoking and nonsmoking sections and 10 completely non-smoking premises were performed. A fast responding nephelometer DustTrak was used to monitor PM2.5.
Each sample was taken in four microenvironments: (i) outdoors in front of the particular restaurant, (ii) indoors in the smoking section, (iii) indoors in the non-smoking section and (iv) again outdoors. The venues were divided into 3 groups according to the type of separation of the smoking and non-smoking sections.
The highest difference in the PM2.5 levels between the smoking and smoke-free sections were found in restaurants with their complete separation. The smoking section had 2.5 times higher concentrations than the non-smoking one.
The difference between the smoking section and the outdoor microenvironment was approximately 15 times. In the partially separated sections the difference between the smoking and non-smoking sections was 1.7 times with the smoking section having 15 times higher aerosol concentrations than outdoors.
No difference was found in the restaurants with non-separated sections (1.1 times). The smoking sections in this type had approx. 30 times higher aerosol levels than outdoors.
In the non-smoking restaurants the difference between the outdoor and indoor concentrations was negligible (1.1 times higher indoors). The results showed that separation of smoking and non-smoking sections in most of the Czech restaurants is not sufficient resulting in inhalation of environmental tobacco smoke also by non-smokers.
Our findings can serve as a good argument for implementation of stricter anti-smoking measures, similarly as in many other countries.