As part of a Europe-wide project the amount of exposure to environmental tobacco smoke (ETS) in public places like schools, restaurants, and public transport facilities was investigated. Three methods were applied: nicotine passive samplers (with a filter treated with sodium bisulphate), the same filters with an active sampling device, and the measurement of fine particles' active surface by unipolar diffusion charging. Settings were selected where either high or low ETS concentrations were expected and where non-smokers would have to stay or at least to pass by. Highest ETS concentrations were found in discos (mean nicotine concentration 154.4 maximum 487.1 microg/m3) and intermediate concentrations in restaurants with no significant difference between smoking (21.3 +/- 6.1 microg/m3) and non-smoking areas (23.3 +/- 15.9 microg/m3) but on average higher values in restaurants with no separation between smoking and non-smoking areas (38.0 +/- 60.6 microg/m3). Concentrations usually below 10 microg/m3 were found in transport facilities (8.9 +/- 8.0 microg/m3, maximum 20.6 in the restaurant section of a railway station's waiting room) and in schools (3.0 +/- 4.6 microg/m3). In hospitals "problem spots" were sought and so concentrations from very low to as high as 45.1 microg/m3 next to a smoking area with no physical barrier or separation and 47.7 microg/m3 inside a smoking room could be documented (21.4 +/- 39.3 microg/m3). The fine particle's surface correlated well with the nicotine concentration (r = 0.8; p < 0.001). Only in one instance (in a pizza restaurant on a busy road with heavy duty diesel traffic and the sampling spot next to the pizza stove) high concentration of fine particles was detected without high nicotine. Tobacco smoke is a key source of indoor fine particles. Health policy must intervene to change the situation found at present in many public places in Austria.