Environmental tobacco smoke (ETS) is one of the most important sources for indoor air pollution and a substantial threat to human health, but data on the concentrations of the trace metals cerium (Ce) and lanthanum (La) in context with ETS exposure are scarce. Therefore the aim of our study was to quantify Ce and La concentrations in indoor air with high ETS load.
In two subsequent investigations Ce, La and cadmium (Cd) in 3 smokers' (11 samples) and 7 non-smokers' (28 samples) households as well as in 28 hospitality venues in Southern Germany were analysed. Active sampling of indoor air was conducted continuously for seven days in every season in the smokers' and non-smokers' residences, and for 4h during the main visiting hours in the hospitality venues (restaurants, pubs, and discotheques).
In terms of residences median levels of Cd were 0.1 ng/m(3) for non-smokers' and 0.8 ng/m(3) for smokers' households. Median concentrations of Ce were 0.4 ng/m(3) and 9.6 ng/m(3), and median concentrations of La were 0.2 ng/m(3) and 5.9 ng/m(3) for non-smokers' and for smokers' households, respectively. In the different types of hospitality venues median levels ranged from 2.6 to 9.7 ng/m(3) for Cd, from 18.5 to 50.0 ng/m(3) for Ce and from 10.6 to 23.0 ng/m(3) for La with highest median levels in discotheques.
The high concentrations of Ce and La found in ETS enriched indoor air of smokers' households and hospitality venues are an important finding as Ce and La are associated with adverse health effects and data on this issue are scarce. Further research on their toxicological, human and public health consequences is urgently required.